Web viewPhotosynthetic microorganisms (both prokaryotic and eukaryotic) are able to generate electrical current that can be harvested by a suitable anodic electrode, in some

Biohybrid Solar Cells 2016 Programme and Abstracts

MEETING PROGRAMME

Thursday 4th August, 2016

15.00 – 18.00 Arrival and check-in

18.00 Dinner

Session 1. Chair: Raoul Frese

19.30 – 20.00 T1 Funneling photons: strategies to enhance applied photosynthesis Barry Bruce, University of Tennessee at Knoxville, USA

20.00 – 21.00 K1 Keynote Lecture - Direct electricity production from photosynthetic microorganismsChris Howe, University of Cambridge, UK

Friday 5th August, 2016

07.30 – 09.00 Breakfast

Session 2. Chair: Nicolas Plumere

09.00 – 09.30 T2 Photosystem I from the thermophilic cyanobacterium Thermosynechococcus elongatus and other pigment-protein complexes for photobiotechnology Heiko Lokstein, Charles University in Prague, Czech Republic

09.30 – 10.00 T3 Photosystem I composite coatings for solar energy conversionKane Jennings, Vanderbilt University, USA

10.00 – 10.30 T4 Biomimetic nanotubes of self-assembled metal chlorophyll derivatives and observation oftheir photocurrentsShoji Sunao, Ritsumeikan University, Shiga, Japan

10.30 – 11.00 Coffee break

11.00 – 11.30 T5 Design and engineering of protein-pigment building blocks for solar energy harvestingsystemsDror Noy, Migal-Galilee Research Institute, Kiryat Shmona, Israel

11.30 – 12.30 K2 Keynote Lecture – Electrochemical communication between photosynthetic membranes/cells and electrodes for harvesting solar energyLo Gorton, Lund University, Sweden

12.30 – 13.30 Lunch

Session 3. Chair: Mike Jones

13.30 – 14.00 T6 Solar to hydrogen devices based on molecular componentsRemko Detz, University of Amsterdam, The Netherlands

14.00 – 14.30 T7 Hacking photosynthesis: bio-hybrid pigment-protein photoelectrodesVincent Friebe, VU University Amsterdam, The Netherlands


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15.00 – 16.30 Poster Flashes and Discussion Session

16.30 – 18.00 Poster viewing

18.00 – 19.30 Dinner

Session 4. Chair: Raoul Frese

19.30 – 20.30 K3 Keynote Lecture - Mimicking photosystems: decaheme cytochromes as molecularelectron conduits in semiconductor nanoparticle photoanodesLars Jeuken, University of Leeds, UK

Saturday 6th August 2016

07.30 – 09.00 Breakfast

Session 4. Chair: Mike Jones

09.30 – 10.00 T8 Self-assembly of bacterial photosynthetic membrane protein-pigment complexes onto electrodesMasaharu Kondo, Nagoya Institute of Technology, Japan

10.00 – 10.30 T9 Hybrid photosynthetic assemblies with enhanced functionSebastian Mackowski, Nicolaus Copernicus University, Poland


11.00 – 11.30 T10 Biopassivation of the biohybrid p-doped silicon electrode with cytochrome c553

Joanna Kargul, University of Warsaw, Poland

11.30 – 12.00 T11 Photosynthetic proteins in devices – the hurdle of charge recombinationHuijie Zhang, Ruhr-Universität Bochum, Germany

12.00 – 13.00 Lunch

Session 5. Chair: Barry Bruce

13.00 – 13.30 T12 Putting life on iron oxide photoelectrodes: proteins, microbes, filmsArtur Braun, Empa-ETH, Switzerland

13.30 – 14.00 T13 Oxygen-evolving porous glass plates containing photosynthetic Photosystem II pigment-protein complexNoji Tomoyasu, Osaka City University, Japan

14.00 – 14.30 T14 Photocurrents from purple bacterial reaction centres and RC-LH1 core complexes in liquidand solid state devices Mike Jones, University of Bristol, United Kingdom


14.45 – 15.45 K4 Keynote Lecture - Coupling photosystem I with electrodes by means of proteins andaromatic compounds Fred Lisdat, Technical University Wildau, Germany

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16.00 – 18.00 Social program

18.00 Dinner

Sunday 7th August, 2016

7.30 – 9.00 Breakfast

10.00 Depart to Maastricht, transfers to main train station and conference building MECC arranged on request

_________________________________________________________________________

ORGANISING COMMITTEE

Raoul Frese, VU University Amsterdam, The Netherlands

Barry Bruce, University of Tennessee at Knoxville, USA

Mike Jones, University of Bristol, United Kingdom

Nicolas Plumeré, Ruhr-Universität Bochum, Germany

ADMINISTRATION

Régine Anmuth, VU University Amsterdam, The Netherlands

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POSTER PRESENTATIONS

# Presenting author TitleP1 Rafal Białek Titanium dioxide as substrate for solar cells based on Rhodobacter sphaeroides

reaction centers

P2 Nathan Brady In vitro interactions between chloroplast transit peptides and envelope lipids: A potential role in protein targeting

P3 Darren Buesen Electrochemical characterization of redox active film roughness

P4 Mmantsae Diale Ultrafast carrier dynamics in hematite thin films probed by femtosecond pump-probe spectroscopy

P5 Katarzyna Dubas Role of protein polarization dynamics in closed reaction centers from Rhodobacter sphaeroides

P6 Krzysztof Gibasiewicz P+HA- recombination in mutant Rhodobacter sphaeroides reaction centers is

weakly temperature-dependent

P7 Daniel Jun Generating photocurrent from HA using a Rhodobacter sphaeroides modified reaction centre with an F(L121)W substitution

P8 Dan Kallmann A complete bio-photo-electro-chemical cell: from cyanobacteria to a hydrogenase thru an alternative Z scheme

P9 Melania Kujawa Electrochemical measurements of PSI-sensitized photovoltaic half-cells

P10 Juntai Liu Engineering of synthetic biohybrid photosystems for solar energy conversion

P11 Magdalena Marszalek Strategies for biohybrid solar cells

P12 Jyotirmoy Mondal Engineering enhanced affinity between ferredoxin and stromal subunits of Photosystem I

P13 Gareth Moore Time constants in photoelectrochemical relaxation processes of metal oxide photoelectrodes

P14 Julian Olmos All-solid-state passivation achieved by successful incorporation of red algal cytochrome c553 at the interface of p-doped silicon and gold

P15 Maxwell T. Robinson Incorporation of Photosystem I proteins with organic and inorganic materials for photocatalytic enhancement

P16 Gadiel Saper Harnessing photosynthesis for H2 production using altered cyanobacteria cells

P17 Karolina Sulowska Quest for SIF-based solar fuel platforms

P18 Sebastian Szewczyk Excitation energy and electron transfer in Photosystem I immobilized on conductive glass

P19 Jens Top In situ photoelectron spectroscopy on a ruthenium complex for electrochemical water oxidation

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PARTICIPANTS

Name Affiliation Email addressRafal Bialek Adam Mickiewicz University, Poznań, Poland [email protected] Brady The University of Tennessee at Knoxville, USA [email protected] Braun Empa, Switzerland [email protected] Bruce The University of Tennessee at Knoxville, USA [email protected] Buesen Ruhr-Universität Bochum, Germany [email protected] Diale University of Pretoria, South Africa [email protected] Detz University of Amsterdam, The Netherlands [email protected] Dubas Adam Mickiewicz University, Poznań, Poland [email protected] Frese VU University Amsterdam, The Netherlands [email protected] Friebe VU University Amsterdam, The Netherlands [email protected] Gibasiewicz Adam Mickiewicz University, Poznań, Poland [email protected] Gorton Lund University, Sweden [email protected] Howe University of Cambridge, United Kingdom [email protected] G Jennings Vanderbilt University, Nashville, USA [email protected] Jeuken University of Leeds, United Kingdom [email protected] Jones University of Bristol, United Kingdom [email protected] Young Jun University of British Columbia, Canada [email protected] Kallmann Technion - Israel Institute of Technology, Israel [email protected] Kargul University of Warsaw, Poland [email protected] Kondo Nagoya Institute of Technology, Japan [email protected] Kujawa Adam Mickiewicz University, Poznań, Poland [email protected] Lisdat Technical University Wildau, Germany [email protected] Liu University of Bristol, United Kingdom [email protected];Heiko Lokstein Charles University, Prague, Czech Republic [email protected] Mackowski Nicolaus Copernicus University, Torun, Poland [email protected] Marszalek VU University Amsterdam, The Netherlands [email protected] Mondal The University of Tennessee at Knoxville, USA [email protected] Moore Empa, Switzerland [email protected] Noy Migal-Galilee Research Institute, Israel [email protected] Olmos University of Warsaw, Poland [email protected] Plumere Ruhr-Universität Bochum, Germany Nicolas.Plumere@ruhr-uni-

bochum.deMaxwell Robinson Vanderbilt University, Nashville, USA [email protected] Saper Technion - Israel Institute of Technology, Israel [email protected];Karolina Sulowska Nicolaus Copernicus University, Torun, Poland [email protected] Shoji Ritsumeikan University, Shiga, Japan [email protected] Szewczyk Adam Mickiewicz University, Poznań, Poland [email protected] Noji Osaka City University, Japan [email protected] Top Empa, Switzerland [email protected] Zhang Ruhr-Universität Bochum, Germany [email protected]

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SPEAKER ABSTRACTS

Keynote Lectures - K

Invited talks - T

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K1 Direct electricity production from photosynthetic microorganisms

Paolo Bombelli and Christopher Howe

Department of Biochemistry, University of Cambridge, United Kingdom

Photosynthetic microorganisms (both prokaryotic and eukaryotic) are able to generate electrical current that can be harvested by a suitable anodic electrode, in some cases using a mediator to transfer electrons from cells to the electrode. Although they are able to generate current in the dark, the output from the microorganisms increases on illumination, and this forms the basis of ‘biophotovoltaic’ devices. The power output obtained from these devices has increased substantially over the last few years, with the maximum reported being in the region of 100 mW m-2, for a mediator-free micro-fluidic device [1]. Estimates suggest that power outputs up to 7 W m -2 should be achievable [2]. A number of parameters have been considered for improving power output in order to reach this goal. These include the availability of electrons from the organisms involved, the export of electrons and transfer to the electrode, and the nature of the anodic and cathodic electrodes. We will discuss the contribution of some of these factors to improving overall power output.

Although the power output from biophotovoltaic devices is lower than from classical photovoltaic systems, the relative simplicity of the former, and their ability to produce some power in the dark, makes them attractive for use in some situations. In addition, they may be useful novel tools for studying the photosynthetic machinery in detail. For example, wild type and mutant cells may show different profiles of change in power output on illumination, and this may help provide insights into the functions of the proteins affected.

We will also discuss the use of ‘plant microbial fuel cells’. These are hybrid devices in which organic material produced by plants as a result of photosynthetic activity is metabolised by heterotrophic microorganisms in the rhizosphere to generate electricity [3].

References[1] Bombelli P, Mueller T, Herling TW, Howe CJ, Knowles TPJ. A high power-

density, mediator-free, microfluidic biophotovoltaic device for cyanobacterial cells. Advanced Energy Materials 5:1401299 (2015).

[2] McCormick AJ, Bombelli P, Bradley RW, Thorne R, Wenzel T, Howe CJ. Biophotovoltaics: oxygenic photosynthetic organisms in the world of bioelectrochemical systems. Energy and Environmental Science 8:1092-1109 (2015).

[3] Strik DPBTB, Timmers RA, Helder M, Steinbusch KJJ, Hamelers HVM, Buisman CJN. Microbial solar cells: applying photosynthetic and electrochemically active organisms. Trends in Biotechnology 29:41-49 (2011).

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K2 Electrochemical communication between photosyntheticmembranes/cells and electrodes for harvesting solar energy

Lo Gorton a , Kamrul Hasana, Galina Pankratovaa, Eva Sperlinga, Hans-Erik Åkerlunda, Per-Åke Albertssona, Dónal Leechb,

Peter ÓConghaileb, Michael A. Packerc

a Lund University, P.O.Box 124, SE-221 00 Lund, Sweden;b National University of Ireland Galway, Galway, Ireland;

cCawthron Institute, 98 Halifax Street, Nelson, New Zealand

Electrochemical transfer between bacterial cells/biological membranes and electrodes can usually be obtained through the use of freely diffusing monomeric redox mediators. Previously we have, however, also shown that flexible osmium redox polymers can work as efficient mediators as well as a convenient immobilisation matrix for a number of both Gram– as well as Gram+ bacteria [1,2]. As a continuation of our work on bacterial cells we have now turned to various photosynthetic organisms/membrane systems. Here we report on electrochemical communication between whole viable photosynthetic bacterial cells [3-5] as well as with eukaryote systems (thylakoid membranes from spinach [6,7], the eukaryote algae [8]) and electrodes through the use of osmium redox polymers. Here we also report on how to increase the efficiency of the charge transfer from the photosynthetic reaction centres to the electrode and to increase the stability of the system as well as the effect of nanostructuring the electrode surface.

References:[1] Hasan, K.; Patil, S. A.; Leech, D.; Gorton, L. Biochem. Soc. Rev., 2012, 40,

1330.[2] Patil, S. A.; Hägerhäll, C.; Gorton, L. Bioanal. Rev., 2012, 4, 159.[3] Hasan, K.; Patil, S. A.; Górecki, K.; Hägerhäll, C.; Gorton, L.

Bioelectrochemistry, 2013, 93, 30.[4] Hasan, K.; Raghava Reddy, K. V.; Eßmann, V.; Górecki, K.; ÓConghaile, P.;

Schuhmann, W.; Leech, D.; Hägerhäll, C.; Gorton, L. Electroanalysis, 2015, 27, 118 .

[5] Hasan, K.; Yildiz, H. B.; Sperling, E.; ÓConghaile, P.; Packer, M. A.; Leech, D.; Hägerhäll, C.; Gorton, L. Phys. Chem. Chem. Phys., 2014, 16, 24676.

[6] Hasan, K., Dilgin, Y.; Cem Emek, S.; Tavahodi, M.; Åkerlund, H.-E.; Albertsson, P.-Å.; Gorton, L. ChemElectroChem, 2014, 1, 131.

[7] Hamidi, H.; Hasan, K.; Emek, S. C.; Dilgin, Y.; Åkerlund, H.-E.; Albertsson, P.-Å.; Leech, D.; Gorton, L. ChemSusChem, 2015, 8, 990.

[8] Hasan, K.; Çevik, E.; Sperling, E.; Packer, M. A.; Leech, D.; Gorton, L. Adv. Energy Mater., 2015, DOI: 10.1002/aenm.201501100.

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K3 Mimicking photosystems: decaheme cytochromes as molecularelectron conduits in semiconductor nanoparticle photoanodes

Ee Taek Hwang1 , Khizar Sheikh1 , Katherine L. Orchard2, Daisuke Hojo3, Valentin Radu1, Chong-Yong Lee2, Emma Ainsworth4, Colin Lockwood4, Manuela A. Gross2,

Tadafumi Adschiri3, Erwin Reisner2, Julea N. Butt4, Lars J. C. Jeuken 1 1School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United

Kingdom; 2Department of Chemistry, University of Cambridge, Lensfield Road , Cambridge, CB2 1EW , United Kingdom; 3Adv. Inst. for Mat. Res., Tohoku

University, 2–1–1 Katahira Aoba-ku Sendai, Miyagi 980–8577, Japan; 4 Centre for Molecular and Structural Biochemistry, School of Chemistry, and School of

Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom ([email protected])

In nature, charge recombination in light-harvesting reaction centers is minimized by efficient charge separation. Here, we show a new approach in which we aim to mimic nature by coupling dye-sensitized TiO2 nanocrystals or CdS quantum dots to the decaheme protein, MtrC and OmcA from Shewanella oneidensis MR-1, where the decahemes form a ~7 nm long molecular wire between the light harvesting nanoparticle (NP) and the underlying anode. The system is assembled by forming a densely-packed decaheme film on an ultra-flat gold electrode, followed by the adsorption of monolayer of NP. TiO2 and CdS NPs were prepared with different organic ligand shells (carboxylic acids and amine groups) and their interaction with the decahemes compared. The step-by-step construction of the decaheme/NP system is monitored with (photo)electrochemistry, quartz-crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM). Interaction between NPs and decahemes is not solely due to electrostatic interactions, as TiO2 nanocrystals with lower (more negative) zeta potential adsorb better on decaheme films than those with less negative charge, while for the CdS quantum dots the opposite is observed. When using TiO2 nanocrystals, dye-sensitized with a phosphonated bipyridine Ru(II) dye, photocurrents are observed that are dependent on the redox state of the decaheme, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the decaheme conduit. In other words, TiO2/decaheme wires function as hybrid photodiodes in which the decaheme traps the conduction-band electrons from TiO2 before transferring them to the electrode. In contrast, when CdS quantum dots are used, the photocurrents are not dependent on the redox state of the decaheme, while cyclic voltammetry shows that the electroactive coverage of the decaheme is diminished upon addition of the CdS layer. This suggest that the CdS either denature the decaheme or replace the decaheme film on the surface and that the observed photocurrent is due to direct electron transfer from the quantum dots to the surface. To the best of our knowledge, the TiO2 nanocrystal/decaheme system is the first demonstration of a photobioelectrochemical system that uses a redox protein to mimic efficient charge separation found in biological photosystems.

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K4 Coupling photosystem I with electrodes by means of proteinsand aromatic compounds

Fred Lisdat

Biosystems Technology, Institute of Applied Life Sciences, Technical University Wildau, Germany

Interaction of material with light can change the electronic situation allowing new reaction pathways and consequently new areas of application. Besides semiconductor materials natural photoactive biomolecules have gained more and more attention in recent years. Studies are mostly focused on increasing the efficiency of photobioelectrocatalysis. Here different aspects have been considered; importantly an effective contact between the large photoenzymatic complexes and electrodes have to be established. The presentation will focus on this aspect and give details on different approaches for establishing electrochemical communication between photosystem I and electrodes. Special attention will be devoted to the modification procedure for adjusting the surface properties of the electrode material1.

In our studies we have used photosystem I from a thermophilic organism (T. elongatus) in order to exploit high light conversion efficiency and to provide sufficient stability for application in a biohybrid system. The first aim is here a fast heterogeneous electron transfer between the membrane protein and the electrode. On this basis effective photocurrent generation can be achieved without applying high overpotential.

One approach is based on the small redox protein cytochrome c. Although not a natural reaction partner of PSI it reacts efficiently and can also show fast heterogeneous electron transfer with electrodes and fast self exchange between the redox protein molecules. This has already provided the basis of several complex arrangements coupling enzymes to electrode surfaces2-4. Cyt c has been used here as assembly template and as wiring agent for PSI1. Not only monolayer arrangements are feasible but also assemblies with multiple layers of PSI. The interaction can be further exploited for a joint assembly of PS1 and cyt c to properly modified surfaces. This allows a tuning of the photocurrent by the number of layers deposited5. Not only the redox protein can provide a proper interface for the assembly of functional PSI molecules. For example, naphtalene derivatives have been found to be suitable electrode modifiers6. This paves the way for the use of other electrode materials. Wavelength dependent measurements of the biohybrid systems verify that the absorption properties of PSI are exploited for efficient photocurrent generation. [1] K. Stieger, S. C. Feifel, H. Lokstein, F. Lisdat, Advanced unidirectional photocurrent generation via

cytochrome c as reaction partner for directed assembly of photosystem I, Phys. Chem. Chem. Phys. 16 (29) (2014) 15667.

[2] F. Lisdat, R. Dronov, H. Möhwald, F.W. Scheller, D.G. Kurth, Self-assembly of electro-active protein architectures on electrodes for the construction of biomimetic single chains, Chem. Comm. 3 (2009) 274

[3] S. C. Feifel, A. Kapp, R. Ludwig, F. Lisdat, Nanobiomolecular multiprotein clusters on electrodes for formation of a switchable cascadic reaction scheme, Angew. Chem. 53 (22) (2014) 5676.

[4] C. Wettstein, K. Kano, D. Schäfer, U. Wollenberger, F. Lisdat, Interaction of Flavin-Dependent Fructose Dehydrogenase with Cytochrome c as Basis for the Construction of Biomacromolecular Architectures on Electrodes, Anal. Chem. (2016) (in press).

[5] K. Stieger, D. Ciornii, A. Kölsch, M. Hejazi, H. Lokstein, S.C. Feifel, A. Zouni, F. Lisdat, Engineering of supramolecular photoactive protein architectures: the defined co-assembly of photosystem I and cytochrome c using a nanoscaled DNA-matrix, Nanoscale (8) 2016 10695.

[6] S.C. Feifel, H. Lokstein, M. Hejazi, A. Zouni, F. Lisdat, Unidirectional Photocurrent of Photosystem I on -System-Modified Graphene Electrodes: Nanobionic Approaches for the Construction of Photobiohybrid Systems, Langmuir 31 (38) (2015) 10590.

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T1 Funneling photons: strategies to enhance applied photosynthesis

Barry D. Bruce

Departments of Biochemistry, Cellular and Molecular Biology,Chemical and Biomolecular Engineering, & Microbiology

SEERC-Sustainable Energy and Education Research CenterThe University of Tennessee at Knoxville, USA

Nature has developed remarkable means for harvesting solar energy to drive the process of photosynthesis. In part, the remarkably high quantum efficiency associated with photosynthesis has been enabled by the successful “division of labor” associated with this process. In nature, organisms have evolved largely separate biomolecular structures that have become specialized to either 1) capture photons and facilitate energy transfer via high-efficiency exciton coupling of pigments and 2) convert this exciton into a charge separation that has a quantum yield approaching unity (via the reaction center complex). Interestingly, the light harvesting process has been very adaptive to capture a wide range of the visible solar energy. Although both the pigments and organization of these light-harvesting complexes demonstrate considerable diversity in plants and algae, the charge separation process is fundamentally conserved. Drawing on the remarkable efficiency, stability and renewability of these biological complexes, we have begun to investigate their ability to function as both photovoltaic devices and light driven catalysts for hydrogen production. I will report on the current strategies to integrate diverse yet natural antennae structures to extend the spectral range of light utilization. This has been shown, in practice, to allow creation of luminescent solar concentrators. Employing synthetic biology may allow us to improve on nature, advancing the design and fabrication of new biohydrid devices. In addition, I will discuss future designs to further enhance their external quantum efficiency toward the goal of a viable, sustainable, and environmentally benign strategy for bioenergy production.

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T2 Photosystem I from the thermophilic cyanobacteriumThermosynechococcus elongatus and other pigment-protein

complexes for photobiotechnology

H. Lokstein1,2, A. Kölsch2, M. Hejazi2, K.R. Stieger3, D. Ciornii3, S.C. Feifel3, D. Kowalska4, S. Mackowski4, R.J. Cogdell5, F. Lisdat3 and A. Zouni2

1Dept. Chemical Physics & Optics, Charles University, Ke Karlovu 3, 12116 Prague, Czech Republic; 2Institut für Biologie/Biophysik der Photosynthese, Humboldt-Universität zu Berlin, Germany; 3Biosystemtechnik, TFH Wildau,

Germany; 4Optics of Hybrid Nanostructures, Nicolaus Copernicus University, Torun, Poland; 5University of Glasgow, UK

Photosystem I (PSI) from the thermophilic cyanobacterium Thermosynechococcus elongatus is exceptionally stable and retains high rates of electron transfer over extended periods of time. Thus, PSI is highly suitable as a model system for artificial photosynthesis as well as for incorporation into bio-hybrid devices for the production of high-value products, incl. solar fuels, and other photobiotechnological applications. PSI can be coupled, e.g., via cytochrome c, to a variety of surfaces/electrodes. These assemblies show promising unidirectional light-induced photocurrents, leading to the prospect of coupling (redox) enzymes onto them for direct electron injection [1,2]. Moreover, PSI was attached to a variety of plasmonic metallic nanostructures (which can act as additional light-harvesting antennae to PSI as well as electrode materials) resulting in exceptionally high fluorescence enhancements of ~ 300 fold [3] which potentially can be translated into enhanced electron transfer rates and/or photocurrents. Other pigment-protein complexes from phototrophic organisms that are promising for biotechnological applications will be discussed as well, cf. e.g., [4].

Acknowledgements: Support by BMBF (Biotechnologie 2020+, Projects 031A154A and B)

References[1] K.R. Stieger, S.C. Feifel, H. Lokstein, F. Lisdat, Advanced unidirectional photocurrent

generation via cytochrome c as reaction partner for directed assembly of photosystem I. PCCP 16 (2014) 15667-74.

[2] S.C. Feifel, H. Lokstein, M. Hejazi, A. Zouni, F. Lisdat, Unidirectional photocurrent of photosystem I on π-system-modified graphene electrodes: nanobionic approaches for the construction of photobiohybrid systems, Langmuir 31 (2015) 10590-10598.

[3] N. Czechowski, H. Lokstein, D. Kowalska, K. Ashraf, R.J. Cogdell, S. Mackowski, Large plasmonic fluorescence enhancement of cyanobacterial photosystem I coupled to silver island films. Appl. Phys. Lett. 105 (2014) 043701.

[4] C. Oesterhelt, E. Schmälzlin, J.M. Schmitt, H. Lokstein, Regulation of photosynthesis in the unicellular acidophilic red alga Galdieria sulphuraria, Plant J. 51 (2007) 500-511.

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T3 Photosystem I composite coatings for solar energy conversion

G. Kane Jennings,1 Maxwell Robinson,1 Faustin Mwambutsa,1 Evan Gizzie,2

Jeremiah Beam,2 Marie Armbruster,1 Clara Simons,1 and David Cliffel2

Departments of Chemical and Biomolecular Engineering1 and Chemistry2

Vanderbilt University, Nashville, TN, USA

Photosystem I (PSI) is a 500 kDa photocatalytic protein complex within the chloroplast granum of photosynthetic organisms that converts incident solar radiation to transfer electrons across the thylakoid membrane with nearly perfect internal quantum efficiency. PSI is extracted from green plants or cyanobacteria and has been successfully employed by several groups across the world as the active photosensitizer within a host of low-cost electrochemical and solid-state photovoltaic architectures. This presentation explores the Vanderbilt group’s recent efforts to prepare coatings in which PSI is integrated with other materials, including semiconductors, graphene oxide, conducting polymers, and natural dyes. These composite assemblies address limitations of PSI, including structural scaffolding, conductivity, and light absorbance. Composite coatings of PSI with conducting polymers can be prepared by either electrochemical co-polymerization from a bath of PSI and aniline or a vapor-phase Friedel-Crafts grafting procedure, whereby dispersed Fe(III) catalyzes rapid growth of conducting polymer from aromatic moieties inherent to PSI. The latter technique avoids the requirements of high temperature and solvent exposure inherent to the fabrication of bulk heterojunctions in organic photovoltaics and can be employed using a library of conjugated monomers with high vapor pressures. The group has recently reported two prototype solid-state devices in which PSI or its composite coatings are deployed between energetically appropriate electrodes. In general, the move toward more effective integration of PSI within these composite, biohybrid coatings has greatly enhanced the turnover frequency of the individual proteins, yielding more efficient utilization of nature’s renewable, mass-produced photodiode.

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T4 Biomimetic nanotubes of self-assembled metal chlorophyllderivatives and observation of their photocurrents

Sunao Shoji and Hitoshi Tamiaki

Graduate School of Life Sciences, Ritsumeikan University, Shiga, Japan

Light harvesting antennas in green photosynthetic bacteria, called chlorosomes, have attracted much attention from the viewpoints of their supramolecular structures and functions. In a chlorosome, a large amount of bacteriochlorophyll(BChl)-c/d/e/f molecules (Figure 1 left) self-assemble without any assistance from the peptides. Their supramolecular assemblies are suggested to be a tube-shaped (or rod-shaped) nanostructure with a 5- or 10-nm diameter or a rolled-up lamella sheet. Recently, we reported the in vitro rod self-assemblies of naturally occuring BChl-c.1,2 Structurally mimicking such chlorosomal self-assemblies, synthetic magnesium, zinc and cadmium chlorophyll derivatives (M-1 in Figure 1 middle) were synthesized as models of natural chlorosomal BChls.3,4 All the three M-1 self-assembled in 1%(v/v) THF and hexane to afford a large oligomer with a red-shifted Qy band at around 740 nm. Cryo-TEM and AFM images showed that the M-1 formed single-wall supramolecular nanotubes with approximately 5 and 3 nm in their outer and inner diameters, respectively (Figure 1 right). Nanotubes of self-assembled M-1 were deposited on an ITO electrode. When nanotubes of M-1 on ITO were irradiated with visible light, cathodic photocurrents were observed in an air-saturated aqueous solution. Action spectrum of Zn-1 self-assemblies was closely similar to its visible absorption spectrum on an ITO, indicating that photoexcited oligomeric Zn-1 would accept an electron from the ITO electrode and donate an electron to an oxygen molecule in an aqueous solution. The chlorosomal single-wall supramolecular nanotubes of M-1 were prepared in the solid state and would be useful as photofunctional materials including solar cells.

Figure 1. Molecular structures of BChl-c/d/e/f (left) and their synthetic models M-1 (middle), and schematic drawing of a supramolecular nanotube of M-1 (right).References1. S. Shoji, T. Mizoguchi, H. Tamiaki, In vitro self-assemblies of bacteriochlorophylls-c from Chlorobaculum

tepidum and their supramolecular nanostructures, J. Photochem. Photobiol. A: Chem., in press, doi: 10.1016/j. jphotochem.2015.11.003 (2016).

2. S. Shoji, T. Mizoguchi, H. Tamiaki, Reconstruction of rod self-aggregates of natural bacteriochlorophylls-c from Chloroflexus aurantiacus, Chem. Phys. Lett., 578, 102–105 (2013).

3. S. Shoji, T. Hashishin, H. Tamiaki, Construction of chlorosomal rod self-aggregates in the solid state on any substrates from synthetic chlorophyll derivatives possessing an oligomethylene chain at the 17-propionate residue, Chem. Eur. J., 18, 13331–13341 (2012).

4. S. Shoji, T. Ogawa, T. Hashishin, S. Ogasawara, H. Watanabe, H. Usami, H. Tamiaki, Nanotubes of Biomimetic Supramolecules Constructed by Synthetic Metal Chlorophyll Derivatives, Nano Lett., 16, in press, doi: 10.1021/acs.nanolett.6b00781 (2016).

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T5 Design and engineering of protein-pigment building blocksfor solar energy harvesting systems

Dror Noy

Migal-Galilee Research Institute, Kiryat Shmona, Israel

The design and construction of small protein functional analogs of photosynthetic proteins is an appealing route toward novel solar energy conversion devices for two important reasons. First, it provides simple models to the elaborate multi-protein multi-cofactor complexes that carry out natural photosynthesis, and thereby a way to study the fundamental engineering principles of biological solar energy conversion and learn how to implement these principles outside their biological context. Second, successful designs may be integrated with artificial and/or natural components into novel hybrid systems for the production of viable solar fuels. Our focus is on natural photosynthetic light-harvesting complexes in which dense arrays of chlorophylls, phycobilins, and/or carotene derivatives are held in place by specific binding proteins. The particular arrangement of chromophores and their specific interactions with the protein environment fine-tune their absorption and emission spectra and allows precise control of the non-radiative energy dissipation processes that prevail in such dense arrays of pigments. This enables regulating the photon fluxes throughout the light harvesting system and directing excitation energy toward its final destination-the reaction center. Achieving precise control on pigment organization and protein pigment interactions is the primary challenge in the design of simple artificial analogs of light harvesting protein-pigment complexes. Here we present a couple of new and promising templates for such designs. The first is based on the conversion of a native highly–conserved transmembrane chlorophyll binding motifs into a water-soluble chlorophyll-binding protein. The second relies on type II water-soluble chlorophyll binding proteins from Brassicaceae plants. These new design prototypes open new possibilities for accurately assembling chlorophyll-protein arrays that may teach us important lessons on controlling photoexcitation dynamics in multi-pigment protein complexes.

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T6 Solar to hydrogen devices based on molecular components

Remko J. Detz and Joost N.H. Reek

University of Amsterdam, Amsterdam, The Netherlands

The development of efficient processes to generate chemical fuel using sunlight as primary energy source can significantly contribute to the total energy demand and diminish our dependence on fossil fuels and nuclear power. The light-driven water splitting reaction to generate molecular hydrogen and oxygen is one of the most promising processes for producing a clean fuel and catalysis plays a crucial role. We want to share our latest efforts in constructing a photoelectrochemical (PEC) cell based on molecular components. The two half reactions, water oxidation (anode-side) and proton reduction (cathode-side), both require their own specialized catalysts, linkages, chromophores, and electrode materials. Initially, these components are made and studied separately, first in solution and subsequently as integrated part of the electrode. The most successful components are combined and studied further in assembled form. This gives insight in the problematic and rate limiting steps of light-driven water splitting using molecular components.

Our latest results on light-driven water oxidation using an Ir-NHC-catalyst [1] and a Pt-porphyrin in solution at pH 7 will be shown [2]. Besides water oxidation, also several DiFe-hydrogenase mimics are prepared and studied to obtain an efficient catalyst, possessing a low overpotential, reversible reduction waves and a high activity [3]. Furthermore, we will elaborate on a Ni-Dubois-type catalyst bonded to a NiO semiconductor surface, which shows electrocatalytic activity in proton reduction in acidic water [4]. These and other findings will be presented at the Biohybrid Solar Cells meeting.

References[1] J.M. Koelewijn, M. Lutz, W.I. Dzik, R.J. Detz, J.N.H. Reek ACS Catalysis 2016, 6, 3418-

3427.[2] H.-C. Chen, D.G.H. Hetterscheid, R.M. Williams, J.I. van der Vlugt, J.N.H. Reek, A.M.

Brouwer, Energy Environ. Sci. 2015, 8, 975-982.[3] R. Becker, S. Amirjalayer, P. Li, S. Woutersen, J.N.H. Reek Science Adv. 2016, 2,

e1501014.[4] B. van den Bosch, J.A. Rombouts, R.V.A. Orru, J.N.H. Reek, R.J. Detz ChemCatChem

2016, 8, 1392–1398.

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T7 Hacking photosynthesis: bio-hybrid pigment-protein photoelectrodes

Vincent M. Friebe 1 , Juan D. Delgado1, David J. K. Swainsbury2, J. Michael Gruber1, Alina Chanaewa1, Rienk van Grondelle1, Elizabeth L. von Hauff1, Diego Millo1,

Michael R. Jones2 and Raoul N. Frese1

1Department of Physics and Astronomy, LaserLaB Amsterdam, VU University Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands;

2School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.

In a quest to fabricate novel solar energy materials, the high quantum efficiency of photosynthetic pigment-proteins is being exploited through their direct incorporation or mimicry in bioelectronic devices such as biosensors and biophotovoltaics[1]. Here I will present our progress in photocurrent generation from bacterial reaction centre-light harvesting 1 (RC-LH1) complexes on conductive metal substrates. From humble beginnings of nano-ampere current densities on bare gold electrodes[2,3], we have quickly climbed to sub-milli amperes densities using a variety of interfacial, surface modification and deposition techniques[4]. Using a Langmuir-Blodgett technique we controlled the orientation and 2-D packing density of these complexes on bare gold, yielding photocurrents densities of approximately 50 µA cm-2 under equivalent 1-sun, and high retained quantum efficiency of up to 50%. However, constrained by the insubstantial light absorption of a single monolayer of pigment proteins we sought to improve this by enhancing the substrate surface area giving way to our best performing bio-hybrid photocathode to date consisting of RC-LH1 on a mesoporous silver substrate. This configuration yielded a peak photocurrent of 166 µA cm-2 under 1 sun illumination, and a maximum of over 400 µA cm -2 under 4 suns, and maintained a relatively high photon to electron conversion efficiency of 30%. The hybridization also benefited from a 2.5-fold increase in RC-LH1 light absorption, due to plasmonic enhancements from the silver nanoparticles as shown using confocal fluorescence microscopy. Nano-structuring of the silver substrate also enhanced the stability of the protein under continuous illumination by almost an order of magnitude relative to a non-structured smooth silver control. The optimization and characterization of the mechanism of electron transfer from the substrate to RC-LH1 via cytochrome and from the RC-LH1 to the electron acceptor quinone critical to the proficiency of all the above mentioned systems will also be discussed.

References[1] M. Kamran, V.M. Friebe, J.D. Delgado, T.J. Aartsma, R.N. Frese, M.R. Jones, Nat. Commun. 2015, 6, 6530; [2] G.J. Magis, M.-J. den Hollander, W.G. Onderwaater, J.D. Olsen, C.N. Hunter, T.J. Aartsma, R.N. Frese, Biochim. Biophys. Acta 2010, 1798, 637; [3] M. Kamran, J.D. Delgado, V. Friebe, T.J. Aartsma, R.N. Frese, Biomacromol. 2014, 15, 2833; [4] V.M. Friebe, J.D. Delgado, D.J.K. Swainsbury, J.M. Gruber, A. Chanaewa, R. van Grondelle, E. von Hauff, D. Millo, M.R. Jones, R.N. Frese, Adv. Funct. Mater. 2015, 26, 285.

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T8 Self-assembly of bacterial photosynthetic membrane protein-pigment complexes onto electrodes

Masaharu Kondo a , Takehisa Dewaa and Mamoru Nangob

aDepartment of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan;

bThe OCU Advanced Research Institute for Natural Science and Technology, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585 Japan

During the primary photosynthetic process, light harvesting complexes (LH1) absorb solar energy and transfer it to the reaction center (RC) in bacterial photosynthetic membranes. The RC converts the absorbed energy into electrochemical energy. These reactions take place within a ‘core complex’ consisting of LH1 complex and RC. Because of our interest in the rapid and efficient energy transfer mechanism between LH1 and RC, we aimed to construct an artificial solar energy device based on a natural solar energy conversion system. In this study, we fused a poly-histidine (His) tag to either the C- or N-terminus of the LH1-α chain of LH1-RC from Rhodobacter sphaeroides IL106. His-tag facilitates the immobilization of the LH1-RC complex on a substrate. The poly-His/LH1-RC complex was immobilized onto a substrate modified with nickel-nitrilotriacetic acid (Ni-NTA) [1]. The poly-His/LH1-RC complex on the substrate was characterized by near-infrared (IR) absorption spectroscopy and photocurrent measurement. The absorption spectrum of the poly-His/LH1-RC complex on the substrate was consistent with that observed in the aqueous solution. This result indicated that the poly-His/LH1-RC complexes were immobilized onto the substrate without denaturation. The cathodic photocurrent generated by the adsorbed LH1-RC complexes depended on the wavelength of the irradiation light and the position of His-tag on LH1-RC. The LH1-RC with the C-terminal His-tag (C-His LH1-RC) on the substrate produced an efficient photocurrent response upon illumination. The LH1-RC with the N-terminal His-tag (N-His LH1-RC), produced little photocurrent upon illumination at any wavelength. The findings of our study indicate that the LH1-RC complexes containing His-tags retained photochemical activity while self-assembling onto a substrate.

References:[1] M. Kondo, K. Iida, D. Takehisa, H. Tanaka, T. Ogawa, S. Nagashima, K. V. P.

Nagashima, K. Shimada, H. Hashimoto, A. T. Gardiner, R. J. Cogdell, and M. Nango Biomacromolecules 2012, 13(2), 432.

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T9 Hybrid photosynthetic assemblies with enhanced function

Sebastian Mackowski

Institute of Physics, Faculty of Physics, Astronomy and InformaticsNicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland

In the presentation we describe several results that demonstrate the potential of hybrid photosynthetic assemblies for enhancing the function of the natural photosynthetic complexes in the context of light harvesting, as well as energy and charge transfer. While the actual architectures are different, the tools used to study them revolve around fluorescence microscopy and spectroscopy techniques, both in steady-state and time-resolved variations. First, a couple of examples where plasmon interactions characteristic to metallic nanoparticles, will be discussed as tools for increasing absorption by pigments comprising the complexes. By proper design of such nanostructures, enhancements reaching a factor of 100 can be achieved. Another result focuses on interfacing light-harvesting complexes with graphene and is derivatives. In addition to studying and understanding basic processes of energy and charge transfer in such hybrid nanostructures, the results point towards unique properties of graphene as energy and charge acceptor. The next observation concerns sensitizing natural light-harvesting complexes with efficient absorbers of the infrared light. We show that for a model system, excitation of such a hybrid nanostructure with infrared light results in emission of natural photosynthetic complexes. This proves the energy transfer between the two structures. Overall, the results of optical spectroscopy of hybrid nanostructures that involve natural photosynthetic complexes, indicate that by proper choice and control of the morphology offer an attractive pathway for manipulating and presumably improving the function of photosynthetic complexes.

Acknowledgements:Research was supported by the WELCOME project “Hybrid Nanostructures as a Stepping Stone towards Efficient Artificial Photosynthesis” from the Foundation for Polish Science, EUROCORES project “BOLDCATS” from the European Science Foundation, Grant ORGANOMET No.: PBS2/A5/40/2014 from the National Research and Development Center, as well as DEC-2013/11/B/ST3/03984, DEC-2013/09/D/ST3/03746 and DEC-2013/10/E/ST3/00034 projects funded by the National Science Center.

References:S. Mackowski, I. Kaminska, Applied Physics Letters 107, 023110/1-4 (2015)J. Grzelak, et al. Applied Physics Letters 105, 163114 (2014)K. Smolarek, et al. Applied Physics Letters 103, 203302/1-4 (2013)D. Kowalska, et al. The Scientific World Journal, 2013, 670412/1-12 (2013)D. Buczynska, et al. Applied Physics Letters 101, 173703/1-4 (2012)Ł. Bujak, et al. Applied Physics Letters, 99, 173701/1-3 (2011) S. Mackowski, Journal of Physics: Condensed Matter 22, 193102/1-17 (2010)

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T10 Biopassivation of the biohybrid p-doped silicon electrodewith cytochrome c553

Julian David Janna Olmos1,2, Phillipe Becquet3, Dominik Gront4, Andrzej Dąbrowski5, Grzegorz Bubak1, Olaf Ruediguer6, Grzegorz Gawlik5, Marian

Teodorczyk5 and Joanna Kargul1

1Solar Fuels Laboratory, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland; 2Faculty of Biology, University of Warsaw,

Miecznikowa 1, 02-096 Warsaw, Poland; 3Carinthia University of Applied Sciences, Europastrasse 4, 9524 Villach, Austria; 4Laboratory of Theory of

Biopolymers, Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland; 5Institute of Electronic Materials Technology, Wólczyńska 133, 01-919 Warsaw, Poland; 6Max Planck Institute for Chemical Energy Conversion,

Stiftstrasse 34 – 36, D - 45470 Mülheim an der Ruhr, Germany.We report a novel method for passivation of a p-doped silicon substrate by employing a biological redox active layer of cytochrome c553 (cyt c553) which is a natural electron donor to PSI in an extremophilic photoautotrophic red microalga Cyanidioschyzon merolae. Nickel nitriloacetic acid-functionalized heavily p-doped Si electrodes were functionalised with five different variants of His6-tagged cyt c553 varying in length and conformational flexibility of the linker peptides that were engineered between the cyt holoprotein and the C-terminal His6-tag, the latter providing the anchoring point to the semiconductor electrode. The five distinct solid-state Si bioelectrodes displayed the typical characteristics of diodes, albeit exhibiting various levels of dark saturation currents depending on the linker peptide used. We show that the cyt c553 variants with long and flexible amino acid chains up to 12 AA in length allow for both, a higher degree of structural flexibility of immobilised cyt c553 and optimal orientation of the haem group in relation to the Si surface, concomitantly providing the best platform for minimization of recombination events at the silicon surface. Indeed, the I-V characterisation of the biodiodes revealed the significant minimization of charge recombination events at the interface of the semiconductor/biological modules depending on the orientation and distance of the haem group of cyt c553 with respect to the Si electrode surface. In this way, biopassivation of p-doped Si was achieved by incorporation of the distinct variants of cyt c that were able to increase the minority carrier lifetimes at the surface of the Si electrode.

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T11 Photosynthetic proteins in devices – the hurdle of charge recombination

Huijie Zhang1, Adrian Ruff2, Volker Hartmann3, Marc M. Nowaczyk3, Matthias Rögner3, Michael R. Jones4, Vincent M. Friebe5, Raoul N. Frese5,

Wolfgang Schuhmann2 and Nicolas Plumeré1

1Center for Electrochemical Sciences, Ruhr-Universität Bochum, Bochum, Germany; 2 Analytical Chemistry, Ruhr-Universität Bochum, Bochum, Germany; 3

Plant Biochemistry, Ruhr-Universität Bochum, Bochum, Germany; 4School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol, United

Kingdom; 5Department of Physics and Astronomy, LaserLaB Amsterdam, VU University Amsterdam, Amsterdam, The Netherlands

Photosynthetic proteins responsible for light harvesting and charge separation can be integrated in devices to produce electricity or chemical fuels. We exploit redox hydrogels to immobilize and electronically contact photosynthetic proteins to electrodes. Previously, we have demonstrated that the redox potentials of the electron relays and the properties of the polymeric supporting matrix can be tuned to enable benchmark current densities (300 μA/cm2 for PS1 [1] and up to 400 μA/cm2 for PS2 [2]) at low overpotential [1-3]. The conversion of light to electrical or chemical energy relies on charge carriers to collect the high energy electron from the photosystem. This presentation will focus on the recombination of the charge carrier at the photoelectrode, a process that decreases or even annihilates the photocurrent. In particular, in biophotovoltaic cells, the objective of achieving high open circuit voltage is associated to an increased driving force for recombination. The hydrogel film properties as well as the electrode surface chemistry can be tuned to minimize the various charge recombination pathways. This concept opens up the possibility to build photovoltaic cells free of semi-conductor materials.

References:[1] T. Kothe, S. Pöller, F. Zhao, P. Fortgang, M. Rögner, W. Schuhmann, N.

Plumeré Chem. Eur. J., 2014, 20, 11029 – 11034. [2] K. Sokol, D. Mersch, V. Hartmann, J. Z. Zhang, M. M. Nowaczyk, M. Rögner,

A. Ruff, W. Schuhmann, N. Plumeré, E. Reisner. Energy Environ. Sci., 2016, Accepted Manuscript, DOI: 10.1039/C6EE01363E.

[3] V. Hartmann, T. Kothe, S. Pöller, E. El-Mohsnawy, M. M. Nowaczyk, N. Plumeré, W. Schuhmann, M. Rögner Phys. Chem. Chem. Phys., 2014, 16, 11936 - 11941.

Acknowledgements:Financial support by the COST action TD1102 (PHOTOTECH) and the Cluster of Excellence RESOLV (EXC 1069) funded by the Deutsche Forschungsgemeinschaft is gratefully acknowledged.

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T12 Putting life on iron oxide photoelectrodes:proteins, microbes, films

Burkhard Beckhoff5, Florent Boudoire1,2, Artur Braun 1 , Niels Burzan1,2, Mmantsae M. Diale3, Catherine E. Housecroft2, Yelin Hu1,4, Hendrik Kaser5, Michael

Kolbe5, Alexandra Kroll6, Bongjin S. Mun7

1Empa. Swiss Federal Laboratories for Material Science & Technology, Switzerland, 2University of Basel, Switzerland; 3University of Pretoria, South

Africa; 4Ecole Polytechnique Federale de Lausanne, Switzerland; 5Physikalisch-Technische Bundesanstalt, Germany; 6eawag – Swiss Federal Laboratories for Aquatic Research, Switzerland; 7Gwangju Institute of Science & Technology,

Republic of Korea

Photovoltaics for solar electricity and artificial photosynthesis (AP) for solar fuels [1] have evolved separately but there exist early works which evolve biological motifs for energy conversion [2,3]. We have picked up this topic in 2009 and functionalize low cost iron oxide based photoelectrodes with light harvesting proteins for photoelectrochemical cells, which produce solar hydrogen by water splitting [4]. While AP has become a hot topic again [5], we explored further how the bioelectric interface can promote or impede the necessary charge transfer between light harvesting proteins, cyanobacteria or even fully colonized biofilms – and semiconductor photoelectrodes on which the bio-components are covalently attached [6,7]. In addition to the electroanalytical and electrochemical methods, we employ synchrotron based x-ray spectroscopy in order to correlate the electronic structure and transport properties of the highly complex and largely unexplored bio-interfaces.

References:[1] Ciamician, C. Science. 36 (1912) 385–394. [2] Allisson F. Dissertation. ETH Zürich; 1930. http://dx.doi.org/10.3929/ethz-a-

000099148 [3] Tributsch H. Dissertation Techn. Universität München, (1968). [4] D.K. Bora et al., Advanced Functional Materials 2012, 22 (3) 490. [5] A. Thapper et al.; Green 2013; 3(1): 43. [6] D.K. Bora, A. Braun, E.C. Constable, Energy Environ. Sci., 2013,6, 407. [7] A. Braun et al., Chem. Eur. J. 2015, 21(11), 4188.

Acknowledgements:SSAJRP #IZLSZ2-149031; NanoTera Shine #20NA21-145936; SNF R’equip #121306; SNF #137868; SNF #132126; Korean-Swiss Sci. & Tech. Coop. SOPEM-2; Advanced Light Source DE-AC02-05CH11231.

22

http://dx.doi.org/10.3929/ethz-a-000099148

http://dx.doi.org/10.3929/ethz-a-000099148


T13 Oxygen-evolving porous glass plates containing photosynthetic Photosystem II pigment-protein complex

Tomoyasu Noji 1 , Keisuke Kawakami1, Jian-Ren Shen2, Takehisa Dewa3, Mamoru Nango1, Nobuo Kamiya1, Shigeru Itoh4 and Tetsuro Jin5

1The OCU Advanced Research Institute for Natural Science & Technology (OCARINA), Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-

8585, Japan; 2Photosynthesis Research Center, Graduate School of Natural Science and Technology/Faculty of Science, Okayama University, Okayama 700-

8530, Japan; 3Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan;

4Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku Nagoya, Aichi 464-8602, Japan; 5Research Institute for Ubiquitous Energy Device,

National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan.

The development of artificial photosynthetic systems has been largely focused on the coupling of a photo-anode and cathode, wherein the production of hydrogen (or energy carriers) is coupled to the electrons derived from water-splitting reactions. Here we used a hybrid approach to construct an artificial water-splitting system in which, a new photoanodic device was constructed incorporating stable photosystem II (PSII) purified from Thermosynechococcus vulcanus through immobilization within 20- or 50-nm nanopores contained in porous glass plates (PGPs). The PSII complex has a diameter of 20 nm, and can split water efficiently. It was shown that PSII in the nanopores retained its native structure and high photo-induced water splitting activity. The photocatalytic rate (turnover frequency) of PSII in PGP was enhanced 11-fold compared to that in solution, yielding a rate of 50–300 mol e−/(mol PSII s) with 2,6-dichloroindophenol (DCIP) as an electron acceptor. The PGP system realized high local concentrations of PSII and DCIP and enhanced the collisional reactions in nanopores with a low disturbance of light penetration. The system allows a direct visualization/determination of the reaction inside the nanopores, which contributed to the optimization of local reaction conditions. The PSII/PGP hybrid device may significantly contribute to the construction of artificial photosynthesis using water as the ultimate electron source.

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T14 Photocurrents from purple bacterial reaction centres and RC-LH1 core complexes in liquid and solid state devices

Sai Kishore Ravi1, Ngeow Yoke Keng1, Varun Kumar Singh1, Li Ang1, David J.K. Swainsbury4, Swee Ching Tan1 and Michael R. Jones 4

1Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575; 2Department of Biological

Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543; 3Bruker Nano Surfaces Division, #10-10 Helios, 11 Biopolis Way,

Singapore, 138667; 4School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, United Kingdom.

Natural solar energy conversion is facilitated by a diversity of photoreaction centres and their attendant light harvesting pigment-proteins. These self-assemble into complex, membrane-based photosystems in which individual component pigment-proteins are arranged to mediate efficient light harvesting, energy flow to the reaction centres and photochemical charge separation. In recent years there has been increasing interest on the use of natural and engineered pigment-protein complexes in biohybrid systems for solar energy conversion with a view to applications such as photovoltaics, solar fuel synthesis, biosensing and molecular scale electronics. Much of this research has exploited the photosystem from the purple bacterium Rhodobacter sphaeroides, in which a reaction centre (RC) pigment protein interacts with an LH1 light harvesting protein to form the so-called RC-LH1 complex. In previous work we have incorporated RC and RC-LH1 complexes into two-electrode, “sandwich-style” solar cells and shown that these can generate both direct photocurrents under continuous illumination and alternating photocurrents under discontinuous illumination [1]. Factors affecting the symmetry of the alternating currents have been explored [2], as have strategies for boosting the open circuit voltage obtained from such cells through manipulation of the liquid electrolyte [3]. Current profiles from such cells often show spikes of forward and reverse current after light-on and light-off events, with much lower steady-state currents during continuous illumination [1]. These have been shown to be due to limitations imposed by slow diffusional processes associated with liquid electrolytes [4]. In this presentation the photocurrent output from a new design of solid-state, two-electrode solar cells are described and discussed.

References:[1] Tan, S.C., Crouch, L.I., Jones, M.R. and Welland, M.E. (2012) Generation of alternating current

in response to discontinuous illumination by novel photoelectrochemical cells based on photosynthetic proteins. Angewandte Chemie International Edition 51, 6667-6671.

[2] Tan, S.C., Yan, F., Crouch, L.I., Robertson, J., Jones, M.R. and Welland, M.E. (2013) Superhydrophobic carbon nanotube electrode produces a near-symmetrical alternating current from photosynthetic protein-based photoelectrochemical cells. Advanced Functional Materials 23, 5556-5563.

[3] Tan, S.C., Crouch, L.I., Mahajan, S., Jones, M.R. and Welland, M.E. (2012) Increasing the open circuit voltage of photoprotein-based photoelectrochemical cells by manipulation of the vacuum potential of the electrolytes. ACS NANO 6, 9103-9109.

[4] Friebe, V. M., Delgado, J. D., Swainsbury, D. J. K., Gruber, J. M., Chanaewa, A., van Grondelle, R., von Hauff, E. L., Millo, D., Jones, M. R. and Frese, R. N. (2016) Plasmon enhanced photocurrent of photosynthetic pigment-proteins on nanoporous silver. Advanced Functional Materials 26, 285-292

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POSTER ABSTRACTS

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P1 Titanium dioxide as substrate for solar cells based on Rhodobacter sphaeroides reaction centers

R. Białek 1 , M.R. Jones2 and K. Gibasiewicz3

1Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz University, Poznań, Poland ([email protected]); 2School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, United Kingdom; 3Molecular Biophysics Division, Faculty of Physics, Adam Mickiewicz

University, Poznań, Poland

There is plenty of different constructions of solar cells based on photosynthesis. Most of them consist of photosynthetic proteins attached to some solid-state or polymer substrate. In this poster solar cells based on photosynthetic reaction centers (RCs) of the purple bacterium Rhodobacter sphaeroides and titanium dioxide are considered. The proposed construction is similar to that of Dye Sensitized Solar Cells invented by Michael Graetzel, which consist of a TiO2 mesoporus layer covered with a photoactive dye, but where natural pigment-proteins are used instead of the artificial dye [1]. For the described research, new genetically engineered RCs were used in which a titanium dioxide binding peptide tag was added. For construction of solar cells a homemade TiO2 paste with 50 nm particles was used. Steady-state absorption spectra of RCs on TiO2 substrates are presented to prove the effectiveness of binding of RCs. Photocurrents generated were either positive (injection of electrons from RCs to substrate) or negative (injection of electrons from substrate to RCs) depending on the composition of the electrolyte solution. Values of the currents obtained were of the order of a few microamperes. For explanation of the observed photocurrents, a mechanism connecting fractions of open and closed RCs was proposed. Negative photocurrent was attributed to RCs in the “open state” whereas the positive one to RCs in “closed state”. It is also supposed that the varying position of the conduction band of TiO2 under various conditions is the reason of the bidirectional current. Understanding of this mechanism will hopefully enable further optimization of our prototype solar cell. It is proposed by Lukashev et al. [2] that the electron is injected from the triplet state in RC so spectroscopic results of mutants with different triplet formation yield will be presented.

References:[1] B. O’Regan, M. Grätzel, A low-cost, high-efficiency solar cell based on dye-

sensitized colloidal TiO2 films, Nature. 353 (1991) 737–740.[2] E.P. Lukashev, V.A. Nadtochenko, E.P. Permenova, O.M. Sarkisov, A.B.

Rubin, Electron phototransfer between photosynthetic reaction centers of the bacteria Rhodobacter sphaeroides and semiconductor mesoporous TiO2 films, Dokl. Biochem. Biophys. 415 (2007) 211–216.

Acknowledgements:We acknowledge financial support from the Polish government and European Union (project entitled “Construction of photovoltaic cells based on Rhodobacter sphaeroides reaction centers” no. 18/POIG/GP/2013).

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P2 In vitro interactions between chloroplast transit peptides and envelope lipids: A potential role in protein targeting

Nathan G. Brady1, Kristen N. Holbrook1, Francesco N. Barerra1 and Barry D. Bruce1,2

1Department of Biochemistry and Cellular & Molecular Biology and 2Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville,

TN, USA ([email protected])

The lipid profile of the chloroplast outer membrane (OM) is distinct from all other membranes exposed to the cytosol. This membrane consists primarily of five constituents: Dipalmitoylphasphatidylcholine (DPPC), digalactosyldiacylglycerol (DGDG), monogalactosyldiacylglycerol (MGDG), phosphatidylglycerol (PG) and sulfoquinovosyldiacylglycerol (SL). Although the lipid composition of the plastid envelope has been elucidated for many plastids (green and non-green) there is less known about properties of this membrane and it has been shown that chloroplast targeting sequences (transit peptides) interact with artificial membrane in a lipid class specific way. In this work we extend this investigation by utilizing the Langmuir-Blodgett trough technique to make lipid monolayers to serve as a chloroplast OM mimetic, and find suitable concentrations of lipids that would be stable at permissive surface pressures to allow for the insertion of the full-length transit peptides from the RuBisCO small subunit precursor. Representative models of the entire lipid composition of the chloroplast OM were carried out as well as biphasic mixtures, to gain insight as to which of these lipid classes are most important for the insertion of the peptide, furthering our understanding of the overall interaction or driving force of peptide insertion into the OM. Insertion experiments were carried with a phosphate buffered aqueous subphase, in which the lipids and peptide were inserted laterally at the interface. The change in surface pressure (π) was monitored using a platinum Wilhemy balance and increases of ≥10 mN/m were observed upon addition of the peptide, suggesting direct insertion into the membrane. This insertion is dependent on the lipid composition of the monolayer as well as the lateral packing pressure of the monolayer. Using the dipper function of the LB trough, we were then able to investigate the structure and orientation of these peptides using an oriented-circular dichroism (OCD) spectrometer. Future work will investigate the distribution and structure of the peptides using AFM and FTIR.

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P3 Electrochemical characterization of redox active film roughness

D. Buesen and N. Plumeré

Center for Electrochemical Science (CES) – Ruhr-Universität Bochum, 44780 Bochum, Germany. ([email protected])

The usefulness and potential of redox films for electrocatalytic [1] and photoelectrochemical [2] applications has been shown in the recent literature. The film thickness (d) and its homogeneity define the electrocatalytic performance and protection properties. Hence, for the optimization of such films toward practical applications, relevant and reliable methods for the characterization of the average thickness as well as of the thickness distribution within the film must be in place. The use of electrochemical methods are especially relevant in this regard because they allow for the determination of the film thickness distribution in the hydrated state, which corresponds to the actual operating conditions of such films. Through a combination of chronocoulometry, interdigitated electrode array, as well as fast scan rate linear sweep voltammetry measurements, the surface coverage in redox molecules (Γ), their concentration (C) and the apparent diffusion coefficient of the electron (D) can be determined which then opens the possibility to calculate d [1]. Going further, LSV measurements covering the full range of slow to fast scan rates can then be used for the determination of the underlying thickness distribution, from which the four standard amplitude roughness parameters (average roughness, root-mean square roughness, skewness, and kurtosis) can be calculated. In this work, thickness distributions were described in terms of a Weibull distribution with variable shape parameter. A previous model for the determination of d, which is based on an analytical solution of the boundary value problem, assumed a homogeneous film layer [3]. However, by the use of numerical simulation, in particular, the finite element method (FEM), the effect of non-homogeneity of the film thickness due to random surface roughness can be probed and quantified.

References[1] V. Fourmond, S. Stapf, H. Li, D. Buesen, J. Birrell, O. Rüdiger, W. Lubitz, W.

Schuhmann, N. Plumeré, C. Léger, J. Am. Chem. Soc., 2015, 137, 5494-5505.

[2] T. Kothe, S. Pöller, F. Zhao, P. Fortgang, M. Rögner, W. Schuhmann*, N. Plumeré*, Chem. Eur. J., 2014, 20, 11029 – 11034

[3] K. Aoki, K. Tokuda, H. Matsuda, J. Electroanal. Chem., 1983, 146, 417-424.

Acknowledgement. Financial support by the Cluster of Excellence RESOLV (EXC 1069) funded by the Deutsche Forschungsgemeinschaft is gratefully acknowledged.

28


P4 Ultrafast carrier dynamics in hematite thin films probed by femtosecond pump-probe spectroscopy  

 M. Diale 1 , A.T. Paradzah1, K. Maabong1, T.P.J. Kruger1

1Department of Physics, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa

α-Fe2O3   has  in recent decades become a subject of intense research for possible applications as water oxidation electrodes. Due to its small bandgap of 2.1 eV,  α-Fe2O3 absorbs in the visible region,  making it a suitable material for fabrication of dye-sensitized solar cells. It is necessary to understand the charge carrier dynamics of electrons and holes after light illumination to be able to successfully use the material for solar cell fabrication. Several processes may occur in α-Fe2O3 at an ultrafast timescale after illumination with light of sufficient energy, e.g., ligand-to-metal charge transfer and d-d transitions in Fe2+. Of particular importance is to understand the electron-hole recombination dynamics as this directly determines the suitability of the material in solar cells. In this study, the carrier dynamics of photo-generated electrons and holes in α-Fe2O3  thin films were investigated using femtosecond pump-probe spectroscopy. An ultrashort (~200 fs) pump pulse centred at 387 nm (3.02 eV) was used and white light  spanning the visible region was used for probing the excited-state dynamics of the photo-generated electrons and holes. A ground-state bleach is observed at wavelengths below 470 nm (2.64 eV) while longer wavelengths are characterized by excited state absorption features. The observed bleach is a result of the excitation of electrons from the valence band to the conduction band of the material. The excited state absorption features observed at longer wavelengths are mainly a result of ligand-to-metal charge transfer and the relaxation of hot electrons within the conduction band. The results are used to approximate the electron-hole recombination rates, which are related to the electronic structure of  α-Fe2O3. The effect of varying excitation pump pulse energy on the carrier dynamics on femtosecond to nanosecond timescales will be discussed. 

Fig 1: Kinetics traces at different wavelengths

29


P5 Role of protein polarization dynamics in closed reaction centersfrom Rhodobacter sphaeroides

K. Dubas1, M. Baranowski2, A. Podhorodecki2, M.R. Jones3 and K. Gibasiewicz1

1Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland; 2Department of Experimental Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland; 3School of

Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, United Kingdom

The influence of protein dynamics on ultrafast processes such as biological electron transfer in light activated systems is still unknown in detail. Electron transfer in Rhodobacter sphaeroides reaction centers from reduced bacteriopheophytin, HA-, to oxidized dimeric bacteriochlorophyll, P+, may be monitored both by transient absorption and time-resolved fluorescence. This recombination reaction measured with both these techniques is characterized by similar multiexponential decay with three lifetimes of ~0.6-0.7 ns, ~2-4 ns, and ~10-18 ns [1,2]. On the basis of the collected data a kinetic-energetic model was proposed. According to this model the electron transfer from HA- to P+ occurs with transient formation of the state P+BA-. The model allows calculation of the free energy levels of the states P+BA- and P+HA- relative to that of the excited state of P, P*. The results show that the free energy gap between P* and P+HA- increases in time in response to protein reorganization, whereas the free energy gap between P* and P+BA- decreases. The most likely explanation of this result is the effect of the protein polarization which stabilizes the state P+HA- and destabilizes the state P+BA-.

Acknowledgements:K.G. acknowledges financial support from the National Science Center, Poland (project entitled ”Bio-semiconductor hybrids for photovoltaic cells” no. 2012/07/B/NZ1/02639.

References:[1] Gibasiewicz, K.; Pajzderska, M.; Dobek, A.; Karolczak, J.; Burdziński, G.;

Brettel, K.; Jones, M. R. Analysis of the temperature-dependence of P+HA-

charge recombination in the Rhodobacter sphaeroides reaction center suggests nanosecond temperature-independent protein relaxation. Phys. Chem. Phys. 2013, 15, 16321-16333.

[2] Woodbury, N. W. T.; Parson, W. W. Nanosecond fluorescence from islolated photosynthetic reaction centers of Rhodopseudomonas sphaeroides. Biochim. Biophys. Acta 1984, 767 (2), 345-361.

30


P6 P+HA- recombination in mutant Rhodobacter sphaeroides

reaction centers is weakly temperature-dependent

K. Gibasiewicz 1 , R. Białek1, M. Pajzderska1, J. Karolczak1, G. Burdziński1, M.R. Jones2 and K. Brettel3

1Department of Physics, Adam Mickiewicz University, Poznań, Poland. ([email protected]); 2School of Biochemistry, Biomedical Sciences Building,

University of Bristol, University Walk, Bristol, BS8 1TD, United Kingdom; 3Laboratoire Mécanismes Fondamentaux de la Bioénergétique, UMR 8221, CEA -

iBiTec-S, CNRS, Université Paris Sud, 91191 Gif-sur-Yvette, France

One of the possible electron donors to artificial substrate or to electrolyte in photovoltaic constructions involving Rhodobacter sphaeroides reaction centers (RC) is reduced primary electron acceptor, a bacteriochlorophyll molecule, HA-. In open RC, with free forward electron transfer, the lifetime of HA- is only about 200 ps. In closed RC, when forward electron transfer from HA- to the next electron acceptor, quinone QA, is blocked, the lifetime of HA- increases to nanoseconds [1]. We demonstrate that in contrast with findings on the wild-type RC, the P+HA-

PHA charge recombination is only weakly dependent on temperature between 78 and 298 K in three mutants with single amino acids exchanged in the vicinity of primary electron acceptors [1]. These mutated reaction centers have diverse overall kinetics of charge recombination, spanning an average lifetime from ~2 to ~20 ns. In order to explain the obtained results we apply protein relaxation model describing temporal evolution of the free energy level of the state P+HA-

relative to P+BA-. We conclude that the observed variety in the kinetics of charge recombination, together with their weak temperature dependence, is caused by a combination of three factors that are each affected to a different extent by the point mutations in a particular mutant complex. These are: (1) the initial free energy gap between the states P+BA- and P+HA-, (2) the intrinsic rate of P+BA- PBA charge recombination, and (3) the rate of protein relaxation in response to the appearance of the charge separated states. In the case of a mutant which displays rapid P+HA- recombination, most of this recombination occurs in an unrelaxed protein in which P+BA- and P+HA- are almost isoenergetic. In contrast, in a mutant in which P+HA- recombination is relatively slow, most of the recombination occurs in a relaxed protein in which P+HA- is much lower in energy than P+BA-. The details of the modelling will be presented.

Acknowledgements:K.G. acknowledges financial support from the National Science Center, Poland (project entitled ”Bio-semiconductor hybrids for photovoltaic cells” no. 2012/07/B/NZ1/02639.

References:[1] Gibasiewicz, K., Białek, R., Pajzderska, M., Karolczak, J., Burdziński, G.,

Jones, M.R., Brettel, K. „Weak temperature dependence of P+HA−

recombination in mutant Rhodobacter sphaeroides reaction centers” Photosyntesis Research 128 (2016) 243-258.

31


P7 Generating photocurrent from HA using a Rhodobacter sphaeroides

modified reaction centre with an F(L121)W substitution

Daniel Jun1, Ali Mahmoudzadeh2, John Madden2, and J. Thomas Beatty1

1Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada; 2Department of Electrical and Computer Engineering,

University of British Columbia, Vancouver, Canada

The study of bacterial photosynthesis and electron transfer in the charge-separation process has mainly revolved around the pigment-protein reaction centre (RC) complex from the purple non-sulphur bacterium Rhodobacter sphaeroides. As such, there is a huge wealth of data with which we can use to generate new mutants to try to engineer artificial electron transfer pathways in the protein. We created a new RC mutant that was the next iteration in a line of mutations that had been previously studied by our group or others. To facilitate oriented binding to the RC surface using cysteine, all five native cysteines were replaced by either serine or alanine to minimise unwanted or non-specific binding; furthermore, three cysteines were added to the surface of the RC to promote binding to highly-ordered pyrolytic graphite (HOPG) electrode via an N-(1-pyrene)maleimide linker. In order to extract electrons from HA, QA was removed with an A(M260)W mutation that had been studied previously, preventing the formation of the charge-separated P+QA- state. Finally, the F(L121)W substitution was made in the hope that the tryptophan would bridge HA and an external electron acceptor, resulting in the mutant M256/L121-Cys. After binding the mutant to HOPG, our preliminary data indicate direct electron transfer and currents up to 25 nA upon illumination. Therefore, it is possible to create an artificial electron transfer pathway, and may lead to extraction of electrons at various potentials or regions of the RC.

Acknowledgements:Supported by grants from the Natural Sciences and Engineering Research Council of Canada and Genome BC.

32


P8 A complete bio-photo-electro-chemical cell: from cyanobacteria to a hydrogenase thru an alternative Z scheme

Dan Kallmann1,2,3, Gadiel Saper1,2,3, Martin Winkler4, David Adam4, Thomas Happe4, Avner Rotschild3, Gadi Schuster2 and Noam Adir1

1Schulich Faculty of Chemistry, 2Faculty of Biology, 3Faculty of Material Sciences and Engineering, Technion - Israel Institute of Technology. Technion City Haifa

32000 Israel; 4AG Photobiotechnology, Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum.

Many studies focus on fuel production from renewable energy sources, such as sunlight. Since it is available only at daytime sunlight must be converted into fuel, where the solar energy is storable and can be used all day. Here we show a direct hydrogen gas production from sunlight using cyanobacteria. Gently disrupted Synechocystis sp. PCC 6803 (d-Syn) can donate electrons to a graphite electrode and produce H2 gas in a bio-photo-electrochemical cell (BPEC). Surprisingly, the disrupted cells maintain cellular respiration. Consequently, the water splitting protein complex photosystem II remains active for hours, while the isolated complex typically becomes inactivated within minutes. The d-Syn cells can generate photocurrent of 20 ± 3 µA/cm2 at 0.05V (vs. Ag/AgCl) and can produce up to 3 µmol hr-1 mg Chl a-1 of hydrogen gas. No external or artificial electron mediator is added to the system. However, an external bias of 0.7V is required to produce H2. In order to avoid the applied bias, the extracted electrons potential must be reduced. Using a photosensitizer (such as Proflavin or Eosin) which perform light-driven electron transfer to the BPEC (and are then re-reduced by the d-Syn light generated electrons) hydrogen fuel can be produced directly from sunlight without either external bias or sacrificial electron donors. In essence we have designed a hybrid bio-organic system which presents a new type of the well-known Z-scheme, since both d-Syn and the photosensitizer absorb light. Indeed, the two photo-reactions utilize the entire visible range of sunlight.

I am a Ph.D. student at the Grand Technion Energy Program at the Technion - Israel Institute of Technology, working on producing hydrogen fuel from photosynthesis in BPECs. My mentors on this project are Profs. Avner Rothschild (Material Sciences and Engineering), Gadi Schuster (Biology) and Noam Adir (Chemistry). My work has already contributed to two published papers (PLOS one, 2015, DOI: 10.1371/journal.pone.0122616 and Photosynthesis research 2015, DOI:10.1007/s11120-015-0075-3), one more under review and two additional manuscripts on the hydrogen production in the BPEC (mentioned above) are in preparation. The later paper will also describe our collaborations with Prof. Wolfgang Schuhmann's lab at Ruhr University Bochum, Germany, a project funded by the DIP program.

I finished my B.Sc with distinction at Ben-Gurion University of the Negev. My M.Sc. was also in Ben Gurion University and the thesis focused on expressing Bilirubin Oxidase on the surface of yeast cells to catalyze oxygen into water in the cathode of a Bio-Fuel cell. This novel Bio-Fuel cell was the first to use yeast cells as a catalyst in its cathode. This study was published in Chemical Communications 2012, DOI:10.1039/C1CC16207A.

33


P9 Electrochemical measurements of PSI-sensitized photovoltaic half-cells

M. Kujawa1, R. Białek2, S. Szewczyk2, M. Jones3 and K. Gibasiewicz2

1Adam Mickiewicz University, Faculty of Physics, Poznań, Poland, ([email protected]); 2Adam Mickiewicz University, Faculty of Physics,

Poznań, Poland; 3School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, United Kingdom

Dye-Sensitized Solar Cells were first widely introduced by Michael Grätzel in 1991. Their initial architecture, which included a layer of porous semi-conductor with adhered dye, was since then modified in many different ways. One such modification is the exchanging of the dye for photosynthetic proteins, such as bacterial reaction centres or whole plant photosystems [1]. In such cases, these proteins can be treated as nanoscale solar cells.

The aim of my poster is to present the outcomes of electrochemical measurements performed to define the optimal electrolyte for photovoltaic half-cells. Such cells were created based on conductive FTO glass with a titanium dioxide layer, onto which photosystem I proteins from cyanobacteria, algae and plants were transferred.

References[1] E. P. Lukashev, et al. Doklady Biochemistry and Biophysics vol. 415, no. 5,

pp. 211-216, 2007

34


P10 Engineering of synthetic biohybrid photosystems for solar energy conversion

Juntai Liu and Michael R. Jones

School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, United Kingdom

There is growing interest in the adaptation of natural photosynthetic systems for the development of new mechanisms for solar energy conversion. Our research group has an interest in the photovoltaic properties of the purple bacterial photosystem and the adaptation of the native system with synthetic materials for constructions of novel biohybrid materials for solar cells, biosensors and photocatalytic devices [1-3]. Despite the high quantum yield of the primary events of photosynthesis in both plants and bacteria, the principal limit of solar energy conversion is ~10% due to low light saturation levels and selective coverage of the available solar spectrum in individual organisms [4]. Regarding the latter, purple bacteria such Rhodobacter sphaeroides strongly absorb at wavelengths between 720 nm and 950 nm and below 620 nm, but absorb weakly in the window between 620 and 720 nm which is where the light harvesting complexes of plant photosystems absorb strongly. We have been exploring binding interactions between reaction centres (RC) from Rhodobacter sphaeroides and Cadium/Telluride (Cd/Te) water soluble quantum dots (QDs) that absorb at wavelengths below 800 nm. QDs are nanocrystals with intriguing photoluminescence properties that have broad absorbance and emit light as a narrow and symmetric emission band regardless of the excitation input [3]. The size-dependence of QD absorption and fluorescence output enables fine adjustment of the QD’s photoluminescence properties [3]. Therefore, QDs can be considered as an artificial light harvesting complex with tuneable emission that can be used to increase the spectral coverage of an otherwise biological photosystem. Conjugates of RCs and QDs have been visualized by transmission electron microscopy and energy transfer from the QDs to the RCs observed by donor fluorescence quenching experiments. We have also been exploring more complex biohybrid systems that couple QDs to a wider range of light absorbing proteins.

Acknowledgements:Funding is acknowledged from the United Kingdom EPSRC and BBSRC Synthetic Biology Centre for Doctoral Training, the University of Bristol and the BrisSynBio Synthetic Biology Research Centre (BBSRC/EPSRC project BB/L01386X/1).

References:[1] Friebe VM et al Plasmon enhanced photocurrent of photosynthetic pigment-proteins on

nanoporous silver. Adv. Funct. Mat. 2016;26:285-92.[2] Swainsbury DJK, Friebe VM, Frese RN and Jones MR Evaluation of a biohybrid

photoelectrochemical cell employing the purple bacterial reaction centre as a biosensor for herbicides. Biosens. Bioelectron. 2014;58:172-8.

[3] Tan SC, Crouch LI, Jones MR and Welland ME Generation of alternating current in response to discontinuous illumination by novel photoelectrochemical cells based on photosynthetic proteins. Angew. Chem. Int. Ed. 2012;51:6667-71.

[4] Blankenship RE, et al Comparing photosynthetic and photovoltaic efficiencies and recognizing the potential for improvement. Science. 2011;332:805–9.

[5].Yu WW, Qu L, Guo W, Peng X. Experimental determination of the extinction coefficient of CdTe, CdSe, and CdS nanocrystals. Chem. Mater. 2003;15:2854–60.

35


P11 Strategies for biohybrid solar cells

Magdalena Marszalek*, Raoul Frese*, Barry Bruce**, Rienk van Grondelle*

*Dept. of Physics, Vrije Universiteit Amsterdam, The Netherlands; **Biochemistry, Cellular & Molecular Biology & Microbiology Depts, University of Tennessee at

Knoxville, USA

The concept of biohybrid solar cells have been explored by a few groups already1-5. Most of the devices followed the DSC (dye-sensitizes solar cell)6

architecture, where the monolayer of the dye molecules is replaced by the whole pigment-protein complexes, such as PSI (photosystem I). However simple this replacement may sound, it is not very trivial. DSC being an elegant, yet complicated, system itself have been studied intensively for more than 25 years now7. The research has been done on each of the component of the cell: dyes – inorganic and organic, nanostructured TiO2 substrate, electrolytes with varying redox couples, materials for counter electrodes. Apart from breaking efficiency a few records for 3rd generation photovoltaics (certified 11.9%, published over 14%8) it has been learned that changing one single component requires adjustments in the whole system. In order to fabricate an efficient device exploiting DSC concept and benefit from the 95% charge separation efficiency achieved by PSI, one must carefully redesign all components of the solar cell. The challenges consider not only the changes reinforced by the size and shape of the pigment-protein construct, but more importantly the biocompatibility aspect while interfacing nano and biomaterials. The perfectly engineered PSI structure has to stay intact to maintain the unsurpassed charge separation efficiency. I will present a few optimisation strategies in the area of nanostructures for photoanode, anchoring the light sensitive component and electrolyte composition that are and will be applied to build an efficient, reproducible and stable biohybrid solar device.

References:1. Ciesielski, P. N.; Hijazi, F. M.; Scott, A. M.; Faulkner, C. J.; Beard, L.; Emmett,

K.; Rosenthal, S. J.; Cliffel, D.; Jennings, G. K. Bioresource Technology 2010, 101, 3047

2. Mershin, A.; Matsumoto, K.; Kaiser, L.; Yu, D.; Vaughn, M.; Nazeeruddin, M. K.; Bruce, B. D.; Grätzel, M.; Zhang, S. Sci. Rep. 2012, 2

3. Ocakoglu, K.; Krupnik, T.; van den Bosch, B.; Harputlu, E.; Gullo, M. P.; Olmos, J. D. J.; Yildirimcan, S.; Gupta, R. K.; Yakuphanoglu, F.; Barbieri, A.; Reek, J. N. H.; Kargul, J. Adv. Funct. Mater. 2014, 24, 7467

4. Gordiichuk, P. I.; Wetzelaer, G.-J. A. H.; Rimmerman, D.; Gruszka, A.; de Vries, J. W.; Saller, M.; Gautier, D. A.; Catarci, S.; Pesce, D.; Richter, S.; Blom, P. W. M.; Herrmann, A. Adv. Mater. 2014, 26, 4863

5. Gizzie, E. A.; Niezgoda, J. S.; Robinson, M. T.; Harris, A. G.; Jennings, G. K.; Rosenthal, S. J.; Cliffel, D. E. Energy & Environmental Science 2015, 1

6. O'Regan, B.; Grätzel, M. Nature 1991, 353, 7377. Hagfeldt, A.; Boschloo, G.; Sun, L.; Kloo, L.; Pettersson, H. Chem. Rev. 2010,

110, 65958. Kakiage, K.; Aoyama, Y.; Yano, T.; Oya, K.; Fujisawa, J.; Hanaya, M. Chem.

Commun. 2015, 51, 15894

36


P12 Engineering enhanced affinity between ferredoxinand stromal subunits of Photosystem I

Jyotirmoy Mondal 1 , Derek Cashman2, Jerome Baudry1, Barry D Bruce1

1Biochemistry and Cellular and Molecular Biology Department, University of Tennessee-Knoxville, USA; 2Department of Chemistry, Tennessee Technology

University, USA

Ferredoxin (Fd) is responsible for the transfer of electron from the stromal side of the cyanobacterial photosystem I (PSI). Despite extensive research we still do not have an atomic level insight into the details of this interaction. We have previously demonstrated computationally that Fd may dock to PsaC/D/E in two ways that may involve a nearly 180° rotation. Both binding geometries involve intimate contact between the two electrostatically frustrated regions of Fd and that of the three subunits of stromal side of PSI (PasC, PsaD and PsaE). These highly frustrated regions are crucial for the docking of the two proteins but the interaction is not very strong as the biological significance of this interaction is limited to shuttling of reduced Fd from PSI to Fd-NADP oxidoreductase. For applied photosynthesis applications, in a cell free condition, the requirement of enhanced affinity between Fd and stromal PSI is very important considering an enhanced, efficient and faster electron transfer allowing Fd to be used as an intermediary electron acceptor in a bio-hybrid device. We will use these computational models to help design complementary mutations that may increase the affinity and stability of the Fd:PSI complex. Increasing some negatively charged amino acids in the interacting regions of Fd can increase the frustration and lead to a tighter binding to the stromal PSI. Several potential sites are possible to be mutated in both in Fd and stromal subunits of PSI in order to enhance the affinity between the complex. Our first approach is to perform rigid body docking of the mutated Fd and PSI using the AMBER99 force field followed by molecular simulation study to find potential docked complexes with increased affinity which can be followed by further experimental approaches which includes site directed mutagenesis followed by binding efficiency studies using chemical cross-linking, surface plasmon resonance (SPR) and backscattering interferometry.

37


P13 Time constants in photoelectrochemical relaxation processes of metal oxide photoelectrodes

Gareth Moore1,2, Rita Toth1, Mmantsae M. Diale2, Artur Braun1

1Empa. Swiss Federal Laboratories for Materials Science and Technology2University of Pretoria, Pretoria, South Africa

The charge carrier dynamics in metal oxide photoelectrodes is an important materials specific characteristic that can be useful in further understanding the photo-electrochemical water splitting process. We have investigated the time constants of decay in photocurrent the iron oxide (α-Fe2O3) photoanode light chopping experiments. Using a double exponential modelling function we hope to gain insight into both the physical and chemical dynamics at the surface and in the bulk. Modeling Function:

yo+A1 e−(x−xo)

τ1 +A2 e−( x−xo)

τ2

References[1] Energy Environ. Sci., 2012, 5, 7626 [2] J. Am. Chem. Soc. 2012, 134, 16693−16700[3] J. Mater. Chem. A, 2013, 1, 14498-14506[4] J. Am. Chem. Soc. 2012, 134, 4294−4302

AcknowledgementSSAJRP; NanoTera Shine; SNF R’equip; NRF

38


P14 All-solid-state passivation achieved by successful incorporation of red algal cytochrome c553 at the

interface of p-doped silicon and gold

Julian David Janna Olmos1,2, Grzegorz Bubak1, Phillipe Becquet3, Dominik Gront4, Andrzej Dąbrowski5, Olaf Ruediger6, Grzegorz Gawlik5,

Marian Teodorczyk5 and Joanna Kargul1

1Solar Fuels Laboratory, Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw, Poland 02-097; 2Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, Warsaw, Poland, 02-096; 3Carinthia University of Applied Sciences, Europastrasse 4, 9524 Villach, Austria; 4Faculty of Chemistry, University of Warsaw, Pasteura 1, Warsaw, Poland 02-093; 5Institute of Electronic Materials Technology, Wólczyńska 133, Warsaw, Poland 01-919; 6MPI for Chemical Energy Conversion, Postfach 10 13 65 / 45413 Mülheim an der Ruhr, Stiftstrasse 34 - 36 / D - 45470 Mülheim an der Ruhr, Germany.By vacuum-assisted spin coating red algal His6-tagged cytochrome c553 on a Ni-NTA-functionalised heavily p-doped silicon (Si) surface, we have constructed sealed, photoactive biodiodes which display characteristics of both Schottky and p-n diodes. We demonstrate by all-solid-state J-V characterization that direct electron transfer (DET) efficiency depends on the haem group-semiconductor surface distance. Moreover, all cyt c553 based devices exhibit lower dark saturation currents (J0) than the non-biofunctionalised devices. As J0 is a measure of recombination, this novel approach displays great promise for future application in silicon based solar cells. This particular solid-state configuration produced dark currents in the mA range. By engineering different lengths of amino acid linker peptides between the Cyanidioschyzon merolae cytochrome c553 holoprotein and a His6-tag at the C-terminus of the protein, the distance between the Si surface and the haem group was varied. The dark J-V characterization of the resultant all-solid-state biodiodes show that application of short, rigid peptide linkers result in higher dark saturation currents, whereas long, flexible linkers result in lower dark saturation currents. This phenomenon translates to lower J0 values for variants whose haem group have more degrees of flexibility, suggesting that haem group orientation respective to semiconductor surface and linker length plays an essential role in recombination minimisation. Experiments are ongoing to determine how this passivation phenomenon relates to DET, and particularly to address the issue of haem group geometry and orientation with respect to the semiconductor surface in these all-solid-state nanodevices.

39


P15 Incorporation of Photosystem I proteins with organicand inorganic materials for photocatalytic enhancement

Maxwell T. Robinsona, Marie Armbrustera, Clara Simonsb, David E. Cliffelc, G. Kane Jenningsa*

aDepartment of Chemical & Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, USA; bDepartment of Physics, Wofford College, Spartanburg,

SC 29303, USA; cDepartment of Chemistry, Vanderbilt University, Nashville, TN 37235 USA

Among the photosynthetic proteins, Photosystem I (PSI) is notable for achieving the most energetic reduction potential in nature and for its outstanding internal quantum efficiency. Stimulated by absorption of indigo, blue, and red photons, PSI facilitates electron excitation and sub-microsecond cross-membrane transport, all while retaining 1.1 eV of absorbed energy. As such, PSI is a model photodiode and the subject of broad scientific study and engineered emulation.

In this study, we report photovoltage enhancement through application of PSI multilayer films atop TiO2 anodes loaded with the natural dye cyanidin-3-glucoside—extracted from blackberries—and mediated by an aqueous Fe(CN)64-/3-

redox shuttle. The enhancement phenomena is found to be dependent on both the amount of PSI deposited on the surface as well as the concentration of reduced redox group present in the electrolyte solution. We attribute the effect to PSI’s photocatalytic reduction of photogenerated oxidized redox species in solution, which attenuates recombination rates at the dye/electrolyte interface. The blue and red absorption bands of PSI’s light harvesting chlorophylls complement the strong green absorption of the sensitizing dye, allowing for better utilization of the visible spectrum.

In addition, we describe a versatile technique to fabricate photocatalytic composite films containing PSI and a chosen intrinsically conductive polymer (ICP). Iron (III)—a friedel crafts catalyst—is added to protein solutions by way of water soluble FeCl3. Drop casting of these solutions on a substrate of choice is followed by contact with low temperature (40oC) monomer vapor of a well-studied ICP, poly(3,4-etylenedioxythiophene) PEDOT. In minutes, a well-integrated polymer/protein composite is grown. Composite films retain the high conductivity of the used ICP and the characteristic absorbance and photocatalytic capabilities of PSI multilayers. Vapor phase processing allows versatility in choice of underlying substrate.

40


P16 Harnessing photosynthesis for H2 production using altered cyanobacteria cells

Gadiel Saper1,2,3, Dan Kol-Kalman1,2,3, Felipe Conzuelo4, Wolfgang Schuhmann4, Avner Rothschild3, Gadi Schuster2 and Noam Adir1

1Schulich Faculty of Chemistry, 2Faculty of Biology, 3Faculty of Material Sciences and Engineering, Technion - Israel Institute of Technology. Technion City Haifa

32000 Israel; 4Analytical Chemistry-Center for Electrochemical Sciences Ruhr-Universitat Bochum.

In the past 100 years, humans have been using fossil fuels as the main energy resource. Not only is the supply of these fuels dwindling, but the use of these fuels emits carbon dioxide, thus leading to global warming. Previous work from our lab (Larom et al., PNAS 2010) on Synechocystis sp. PCC 6803 appears to allow QA oxidation by an external cytochrome c (cyt. c) suggesting the use of photosynthesis to convert sunlight to electricity. Recently, we have found that mild disruption of Synechocystis cells permits direct electric connectivity to a graphite electrode. Moreover we have found that these disturbed cells maintain cellular structure and cellular respiration explaining the long life time of our bio-photo-electro-chemical cell. Moreover, our experiments confirm that the electrons are extracted from PSII QA and transferred to the electrode via an endogenous mediator. Furthermore, we use this bio-hybrid system to produce hydrogen gas. We propose that these "dead and alive" cells may be that basis for future use as within an organic, nature based, bio-photo-electro-chemical cell with a long-life time.

Acknowledgements: The authors thank the Nancy & Stephen Grand Technion Energy Program (GTEP), the Schulich scholarship and the adelis Foundation for their support. RIP fellowship is supported in addition by The Israeli Ministry of Science, Technology and Space. This work was funded by The I-CORE Program of the Planning and Budgeting Committee, The Israel Science Foundation (Grant No. 152/11), a grant from the transformative program of US-Israel Binational Science Foundation (2011556), and a DIP grant (LU315/17-1) from the Deutsche Forschungsgemeinschaft.

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P17 Quest for SIF-based solar fuel platforms

Karolina Sulowska, Marcin Szalkowski, Julian Olmos, Khuram Ashraf, Heiko Lokstein, Sebastian Mackowski, Richard Cogdell, Joanna Kargul, Dorota Kowalska

Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, PolandCenter of New Technologies, Warsaw University, Banacha 2c, Warsaw, Poland

University of Glasgow, 120 University Place, Glasgow G12 8TA, United Kingdom

Plasmonically active substrates have been considered as potential platforms for enhancing functions of photosynthetic complexes, related to light-harvesting, energy and charge transfer, as well as photochemical catalysis. Among such substrates, a film composed of metallic nanoparticles, such as silver island film (SIF), has been successfully applied to tune the optical properties of naturally evolved light converting biomolecules. In this work we present an overview of recent results obtained for both light-harvesting complexes (peridinin-chlorophyll-protein, PCP, Fenna-Matthews-Olson complex, FMO) and reaction centers from C. tepidum, Photosystem I from T. elongatus, and PSI-LHC1 supercomplex from C. merolae. The structures comprising various photosynthetic complexes on SIF substrates were studied by a variety of fluorescence spectroscopy and microscopy techniques, which allow to determine the effect of plasmons on absorption and emission of the biomolecules, and in addition to discriminate between several processes that emerge at the interface between metallic nanostructures and pigments comprising the complex. Particular focus will be given to summarizing the influence of plasmon excitations in the SIF on the values of obtained enhancement factors and their dependence on the number of chlorophyll molecules in a given complex, and the morphology of the structure. The latter concerns in particular the thickness of the layer containing photosynthetic complexes together with the density of the silver islands on a substrate. The results indicate that enhancement factors exceeding 100 can be obtained for PSI complexes deposited on properly fabricated SIF substrates. This observation can suggest that it should be possible to translate large enhancements of light absorption and activation of natively dark chlorophylls, into improvement of efficiency of charge separation in reaction centers. Thus, hybrid nanostructures based on SIFs can be considered as building blocks for functional solar energy conversion devices.

Acknowledgements: Research was supported by the WELCOME project “Hybrid Nanostructures as a Stepping Stone towards Efficient Artificial Photosynthesis” funded by the Foundation for Polish Science, the EUROCORES project “BOLDCATS” funded by the European Science Foundation, as well as DEC-2013/11/B/ST3/03984 and DEC-2013/10/E/ST3/00034 projects funded by the National Science Center.

References:S. Maćkowski, et al. FEBS Letters, acceptedM. Szalkowski, et al. Photosynthesis Research 127, 103-108 (2016)N. Czechowski, et al. Applied Physics Letters, 105, 043701/1-5 (2014)K. Ciszak, et al. Acta Physica Polonica A 122, 275-278 (2012)N. Czechowski, et al. Plasmonics, 7, 115-121 (2012) S. Mackowski, et al. Nano Letters 8, 558-564 (2008)

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P18 Excitation energy and electron transfer in Photosystem I immobilized on conductive glass

S. Szewczyk1, W. Giera1, S. D’Haene2, R. van Grondelle2 and K. Gibasiewicz1

1Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland; 2Department of Physics and Astronomy, Vrije Universiteit, De

Boelelaan 1081,1081 HV Amsterdam, The Netherlands

Photosystem I (PSI) is one of the photosynthetic proteins used in prototype constructions of bio-inspired solar cells. Unlike in the natural systems, PSI complexes in solar cells are attached to the artificial conducting or semiconducting substrate. The aim of this contribution was to compare the excitation energy and electron transfer in cyanobacterial PSI in solution and immobilized on FTO conductive glass (iPSI). The excitation energy and electron transfer dynamics in monomeric and trimeric PSI complexes from Synechocystics sp. PCC 6803 were studied by time-resolved fluorescence (streak camera) and femtosecond transient absorption. Both in solution and immobilized on FTO, most of PSI complexes remained mostly in the “closed” state with the primary donor oxidized. The time-resolved spectral data were analyzed using global and target analysis.Deposition of PSI on glass preserves biexponential excitation decay of ~4-7 and ~21-25 ps lifetimes characteristic of PSI in solution, but the mean lifetime is significantly shorter in iPSI due to faster excitation quenching by charge separation (~10 ps instead of ~15 ps). This indicates an additional electron transfer route, likely from iPSI to FTO. Interactions between iPSI and FTO and/or between neighboring iPSI complexes influence the number and energetic properties of low-energy or red chlorophylls in iPSI.Additionally, in order to monitor the photochemical activity of PSI immobilized on FTO, photoelectrochemical measurements of iPSI were performed. Chronoamperometric studies revealed ability to generate photocurrent in such complexes.We conclude that dried PSI complexes adsorbed on the FTO surface remain fully functional in terms of excitation energy transfer and primary charge separation that is particularly important in the view of photovoltaic applications of this photosystem.

Acknowledgements:S.S. acknowledges financial support from the Polish Ministry of Science and Higher Education via the “Diamond Grant” (Diamentowy Grant) programme, grant no. DI 2011 004141. K.G. acknowledges financial support from the National Science Center, Poland (project entitled ”Bio-semiconductor hybrids for photovoltaic cells” no. 2012/07/B/NZ1/02639.

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P19 In situ photoelectron spectroscopy on a ruthenium complexfor electrochemical water oxidation

Jens Top1,2, Rita Toth1, Bongjin S. Mun3, Catherine Housecroft2, Artur Braun1

1Empa. Swiss Federal Laboratories for Materials Science and Technology2University of Basel, Basel, Switzerland

3Gwangju Institute of Technology, Gwangju, Korea

Early work on dye sensitization dates back almost 100 years ago (Allisson, 1930) and became a field of energy conversion in the late 1960s and early 1970s (Tributsch and Calvin, 1971). Dye sensitization is basically a technology of artificial photosynthesis (Ciamician, 1912) and is currently being used in dye sensitized solar cells. Ruthenium is a favourite component in high performance dye molecules. We have investigated a novel Ru complex (figure 1) (Besson et al., 2010) of composition Cs9[(γ-PW10O36)2Ru4O5(OH)(H2O)4] and subjected it to electrochemical and photoelectron spectroscopy studies.Three samples were prepared (figure 2): one containing the Ru complex, one containing hematite and the last one a cell as described in figure 4, to carry out in situ photoelectrochemistry.On the first two samples a comparative study was carried out to gauge the effect of the presence/absence of light and/or humidity. Due to the heavy overlap between C 1s and Ru 3d peaks, the interpretation of these results is particularly complicated (see figure 3) but efforts are ongoing to deconvolute these spectra.On the last sample electrochemical measurements were planned, but due to an electrical short these were postponed. Instead a line scan over the entire sample was performed. These are a promising starting point for further studies.

References:ALLISSON, F. 1930. Oxydo-Reduktionen mit Chlorophyll und anderen

Sensibilatoren. Helvetica Chimica Acta, 13, 788-805.BESSON, C., HUANG, Z. Q., GELETII, Y. V., LENSE, S., HARDCASTLE, K. I., MUSAEV,

D. G., LIAN, T. Q., PROUST, A. & HILL, C. L. 2010. Cs9(g-PW10O36)2Ru4O5(OH)(H2O)4, a new all-inorganic, soluble catalyst for the efficient visible-light-driven oxidation of water. Chemical Communications, 46, 2784-2786.

CIAMICIAN, G. 1912. The photochemistry of the future. Science, 36, 385-394.TRIBUTSCH, H. & CALVIN, M. 1971. Electrochemistry of excited molecules -

photo-electrochemical reactions of chlorophylls. Photochemistry and Photobiology, 14, 95-.

Acknowledgements:SSAJRP; KSSTP; NanoTera Shine; SNF R’equip; ALS, DoE SC

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Web viewPhotosynthetic microorganisms (both prokaryotic and eukaryotic) are able to generate electrical current that can be harvested by a suitable anodic electrode, in some