4168

www.advmat.dewww.MaterialsViews.com

CO

MM

UN

ICATI

ON

Jeonghun Kim , Jungmok You , Byeonggwan Kim , Teahoon Park , and Eunkyoung Kim *

Solution Processable and Patternable Poly(3,4-alkylenedioxythiophene)s for Large-Area Electrochromic Films

Interest in electrochromic π -conjugated polymers (ECPs) has recently increased considerably for their tunability of colors, low cost of preparation, and low-voltage operation. [ 1–11 ] Among the ECPs, polymers from heterocyclic monomers containing pyrrole, [ 12 ] thiophene, [ 13 ] and selenophene [ 14–16 ] derivatives have been applied to electrochromic devices for simple fi lm processing and high electrochromic contrast. In particular, recent advances in the synthesis of poly(3,4-alkylenedioxythio-phene)s (PXDOTs) and their derivatives have offered new opportunities for low energy consumption and electrochemi-cally stable transmissive/absorptive electrochromic devices (ECDs) with fast switching times and full color. [ 17–21 ]

As most thin-fi lm applications require patterning processes, the ability to pattern polymers in the thin fi lm state into a microregime is a requirement for the application of such ECPs into information displays. [ 22–27 ] Nonetheless, very few of the ECPs known to date are suitable for photopatterning. [ 24 , 26 ] Sol-uble ECPs could be patterned by photolithography and etching processes, but the syntheses of those polymers are diffi cult due to need for multiple synthetic steps. Moreover, such patternings are complex as they require multi-step wet patterning processes with high cost equipment. [ 26,27 ] Many efforts, including inkjet printing, have been made to overcome these diffi culties, how-ever, these techniques are limited to soluble π -conjugated poly-mers. [ 28–30 ] As most of the highly effi cient PXDOTs are insoluble, they must be patterned through photolithographic methods and have to go through an etching process using a strong acid or base. [ 24 ] On the other hand, we have recently reported the synthesis of new poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives that have a photocrosslinkable group, which allows for the use of direct photopatterning. [ 31 ] In previous etchless direct photopatterning methods, the conjugated polymer, pre-pared by electrochemical polymerization (EP) or vapor-phase poly merization (VPP), experienced twisting of the π -conjugated main chain as the side chain of the polymer was crosslinked by UV light, resulting in a huge conductivity decrease (over 99.99%) with color bleaching of the area exposed to light. [ 31 ] The new method offers conductivity controllability according to the dose of UV exposure and electrochromic patterns on various substrates. Thus, there is a challenge to apply this method to

© 2011 WILEY-VCH Verlag Gwileyonlinelibrary.com

J. Kim , J. You , B. Kim , T. Park , Prof. E. Kim Active Polymer Center for Pattern IntegrationDepartment of Chemical and Biomolecular EngineeringYonsei University50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea E-mail: eunkim@yonsei.kr

DOI: 10.1002/adma.201101900

a conjugated polymer prepared by solution-casting polymeri-zation (SCP), which proceeds through a simple, fast casting process for the coating of large-area devices. Moreover, mono-mers for the SCP process are widely available relative to those for VPP, [ 32,33 ] which requires evaporation. In addition, SCP does not present the expensive equipment requirements of alter-native methods, such as an electrochemical coating system for EP, or a vacuum chamber for VPP. [ 32,33 ] Here, we report photo-patterning of PXDOT derivatives prepared from SCP that are useful for a fl exible large-sized EC display.

In order to prepare photopatternable PXDOTs, 3,4-propylenedioxythiophene-methacrylste (ProDOT-MA) was synthesized according to the modifi ed method for 3,4-ethylenedioxythiophene-methacrylate (EDOT-MA) [ 31 ] (see the Supporting Information for synthesis details, Figure S1). Both ProDOT-MA and EDOT-MA were examined for SCP ( Figure 1 a). Conductive polymer fi lms were prepared as follows. A solu-tion of the monomers containing oxidant and inhibitor was spin-coated onto a substrate followed by heating for 2 min at 60–80 ° C and washing with isopropyl alcohol to remove residual low mole cular weight compounds. As illustrated in Figure 1 a, the ECP fi lms of PProDOT-MA and PEDOT-MA were depos-ited onto a large-area conductive substrates by the SCP method within a few minutes. Thermal polymerization commenced by heating at a temperature between 60–80 ° C, at which the methacry late functional group of both photopatternable poly-mers was intact, as determined from the vibrational peak at 1637 cm − 1 (C = C bond of acrylate). The intensity of the vibra-tional peak for the C = C bond of acrylate (1637 cm − 1 ) remained constant while the peaks at 1540–1480 cm − 1 , originating from the conjugated C = C asymmetric and symmetric stretching vibration of the conjugated polythiophene ring, respectively, were enhanced upon polymerization (Figure S2, Supporting Information). The thickness of the ECP fi lms was 50–250 nm, depending on the spin-coating speed (1500–4000 rpm), and correlated linearly to the spinning speed, as shown in Figure S3 (Supporting Information). Figure 1 b–e illustrate step-by-step the coating methods described above, along with photographic images of the fi lm. Since the SCP method is neither limited by substrate nor its area, it can be applied to large sized ITO fi lms for fabrication of fl exible ECDs.

As shown in the spectroelectrochemical studies pre-sented in Figure 2 , the visible absorption of both PEDOT-MA and PProDOT-MA fi lms (in cyan) bleached extensively with increasing applied potential. This depletion was accompa-nied by the formation of polaronic and bipolaronic transi-tions in the near-IR region, similar to the substituted PEDOT and PProDOT. [ 1 ] When the polymers were fully doped, the absorption decreased (in violet), making them useful as a

mbH & Co. KGaA, Weinheim Adv. Mater. 2011, 23, 4168–4173

www.advmat.dewww.MaterialsViews.com

CO

MM

UN

ICATIO

N

Figure 1 . Structure of photopatternable electrochromic polymers and process of SCP. a) Chemical structures of methacrylate functionalized EDOT-MA and ProDOT-MA monomers and their polymers with a photocrosslinkable group from SCP and schematic representation of fabrication of patterned ECDs using SCP method from patternable conductive polymers and device structure: i) spin-coating of casting solution on conductive transparent electrode at desired spin speed for control of fi lm thickness, followed by drying and facile polymerization either on a hot plate or in an oven for a short time; ii) photopatterning process using UV light with photomask; and iii) ECD fabrication process by inserting electrolyte and sealing with epoxy resin. See the Experimental Section for details. Photographs show: b) the casting solution coated glass, c) the formation of conductive polymer fi lms by heating of (b) for 2 min at 60–80 ° C, d) the fi lm after photopatterning by UV light using a photomask with various patterns, and e) a microscopic image of the circled area with 50 μ m lines.

colored-to-transmissive switching device. Cyclic voltammetry showed that the PEDOT-MA and PProDOT-MA fi lms coated on ITO glass had oxidation potentials of + 0.14 and + 0.3 V versus Ag/AgCl, respectively, (Figure 2 c). The oxidation potential of PProDOT-MA was shifted to more positive values because the electron donating oxygen atoms were separated by the propylene in the ProDOT derivative, which should provide a larger degree of freedom for the movement of the lone pairs of electrons from oxygen atoms. [ 34 ] From the onset of the absorp-tion of PEDOT-MA and PProDOT-MA, the bandgaps of the polymers were determined to be 1.73 and 1.82 eV, respectively, which are the same as those reported for substituted PEDOT and PProDOT. [ 1 ] The color states attained in each confi guration are shown as insets in Figure 2 a,b.

The EC fi lms were directly photopatterned by UV through a photomask, as shown in Figure 1 a (ii), without a wet-etching process. Various patterns formed immediately on the EC fi lm according to the photomask patterns (Figure 1 d,e). While the UV unexposed area remained colored, the UV-exposed area appeared bleached, yielding color contrast and huge conductivity decreases at the bleached area, as we reported

© 2011 WILEY-VCH Verlag GAdv. Mater. 2011, 23, 4168–4173

previously. [ 31 ] To measure the electrical conductivity of polymer fi lms, the fi lms were coated on slide glass by SCP with same a condition of spin coating speed, and then the conductivity was measured by a four-point probe and compared before and after UV exposure. The conductivity changed in the UV-exposed area of the PEDOT-MA and PProDOT-MA fi lms from around 1.5 × 10 − 3 to less than 10 − 7 S cm − 1 and from around 5.6 × 10 − 5 to less than 10 − 8 S cm − 1 via photocrosslinking, respectively. The con-ductivity of the PEDOT-MA fi lm prepared by SCP was smaller than that prepared by VPP; however, the conductivity decrease induced by UV irradiation was much larger (10 4 times) for the fi lm prepared by SCP. Such a large conductivity change induced by UV exposure afforded clear patterns on both PEDOT-MA and PProDOT-MA fi lms. These methods of forming pattern-able π -conjugated ECPs offer an unprecedented facile method for synthesizing large patterned ECDs, without a wet etching patterning process.

Films patterned with the letters “ABC” were successfully fab-ricated as EC devices (5 cm × 2.5 cm) when attached to a solid polymer electrolyte (SPE) layer that was coated on a counter elec-trode (ITO glass). Only the unexposed ABC area showed clear

4169mbH & Co. KGaA, Weinheim wileyonlinelibrary.com

4170

www.advmat.dewww.MaterialsViews.com

© 2011 WILEY-VCH Verlag G

CO

MM

UN

ICATI

ON

wileyonlinelibrary.com

Figure 2 . Spectroelectrochemistry and ECD devices comprised of PEDOT-MA and PProDOT-MA fi lms. a) Spectroelectrochemistry of PEDOT-MA (normalized at the polymer absorption maximum). The fi lm was coated onto ITO glass by the SCP method. The applied potential was increased in 50 mV increments: –0.9 to + 0.6 V vs. Ag wire, and a platinum wire was used as the counter electrode. b) Spectroelectrochemistry of PProDOT-MA (normalized at the polymer absorption maximum). The fi lm was coated onto ITO glass by the SCP method. The applied potential was increased in 35 mV increments: + 0.22 to + 1.13 V vs. Ag wire, and a platinum wire was used as the counter electrode. c) Cyclic voltammogram of PEDOT-MA (red line) and PProDOT-MA (black line) coated onto an ITO glass electrode in 0.1 M LiClO 4 solution, vs. Ag/AgCl (Pt wire as counter electrode). The cyclic voltammogram was obtained at a 50 mV s − 1 scan rate.

400 600 800 10000.0

0.2

0.4

0.6

0.8

1.0

1.2

Ab

sorb

ance

(a.

u.)

Wavelength (nm)

547 nmb)

Ox

Red

680 nm

400 600 800 10000.0

0.2

0.4

0.6

0.8

1.0

1.2A

bso

rban

ce (

a.u

.)

Wavelength (nm)

a)578 nm

716 nm

Red

Ox

-1.0 -0.5 0.0 0.5 1.0

6

4

2

0

-2

-4

-6

-8 PEDOT-MA PProDOT-MA

E vs. Ag/AgCl

I (A

/cm

2)

x 1

0-5

c)

electrochromic switching by the applied potential, exhibiting their characteristic color ( Figure 3 a,b). The UV-exposed area (bleached part) remained bleached due to the loss of electro-chromic properties. Figure 3 c shows the patterned PProDOT-MA fi lm on a fl exible ITO fi lm with 7 in. diagonal ECD (12.6 cm × 12.6 cm) using the SCP method and direct photopatterning.

The electrochromic switching of the patterned fi lms was examined using the transmittance change (EC contrast, Δ T ) by monitoring the transmittance change at the unexposed area. Large optical contrasts of the UV-unexposed area in the PEDOT-MA (thickness: 120 nm) and PProDOT-MA (thickness: 130 nm) fi lms were confi rmed by monitoring the transmittance using a square-wave potential step (–1.5/ + 1.5 V) absorptometry for different switch times from 30 to 5 s (Figure 3 d,e), in a 0.1 M LiClO 4 /PC solution. The absorbance change for the PEDOT-MA fi lm was monitored at 578 nm and exhibited good switching performance of about Δ T = 45.7%, maintaining Δ T ≥ 40% for switching pulse times of 10 s and above. However, with a faster switching pulse of 5 s, the Δ T decreased to 28.1%, possibly due to a slow redox reaction for electrochromism. Similarly, the PProDOT-MA fi lm showed a high Δ T of 41.1% at a switching pulse time of 30 s. Unlike the EC response of the PEDOT-MA fi lm, the PProDOT-MA fi lm showed much less change in Δ T for a different switching times even at a fast switching pulse time of 5 s ( Δ T = 32.7%). The change in Δ T for the PProDOT-MA was 20%, while that for the PEDOT-MA fi lm was 38.5% when the switching time was decreased from 30 to 5 s. This result indicates that the response time of the PProDOT-MA was faster than that of the PEDOT-MA fi lm, possibly due to the increased freedom of electron transfer from the ring oxygen arising from the larger ring size of the ProDOT derivative relative to that of the PEDOT-MA. [ 34 ] The coloration effi ciency (CE) [ 1 ] of the ECD was determined from the optical change under a given charge. The ECD from PEDOT-MA and PProDOT-MA exhibited CE values of 175 and 243 cm 2 C − 1 , respectively, which are compa-rable to those of unsubstituted PEDOT and PProDOT, respec-tively, [ 35 ] and higher than those from inorganic electrochromic materials (15 to 50 cm 2 C − 1 ). [ 36,37 ]

The correspondance of the color changes of the PEDOT-MA and PProDOT-MA fi lms by electrochemical switching to the colorimetric change in L ∗ a ∗ b ∗ color standards was determined on the basis of the Commission Internationale de l’Eclairage (CIE) (1976). [ 38 ] In their oxidation state, the PEDOT-MA and PProDOT-MA fi lm exhibited L ∗ a ∗ b ∗ color coordinates of (65, –5, 1) and (50, –4, –1), respectively ( Figure 4 a). High L ∗ values indicate high transparency at neutral states, while the low values of a ∗ and b ∗ indicate a loss of their colors. [ 20 , 39 ] Upon switching the applied potential to a neutral state, the fi lms exhibited color coordinates of (43, 4, –25) and (35, 16, –10), respectively. The L ∗ values were reduced, refl ecting deep color changes in lightness, and the values of a ∗ and b ∗ changed to represent the specifi c colors of the fi lms at reduced states. The reversible changes of the L ∗ a ∗ b ∗ values between oxidation and reduction states showed clear color switching for ECDs. The PProDOT-MA took on a purple hue, which corresponds to the mixing of a small b ∗ and a large a ∗ values, while the PEDOT-MA fi lm took on blue (large b ∗ and small a ∗ values) in the colored state (Figure 4 a). From the color mixing technology, three major colored (red, blue, and green) materials are necessary to achieve black color

mbH & Co. KGaA, Weinheim Adv. Mater. 2011, 23, 4168–4173

www.advmat.dewww.MaterialsViews.com

CO

MM

UN

ICATIO

N

Figure 3 . Patterned ECDs and polymer electrochromic performance. Window typed patterned electrochromic devices (5 cm × 2.5 cm) composed of a) PEDOT-MA and b) PProDOT-MA coated onto ITO glass by SCP and patterning with a photomask. c) Flexible ECDs using PProDOT-MA (7 in. diagonal, 12.6 cm × 12.6 cm) onto ITO fi lm (inset shows a same sized fl exible ECD without patterning process). The ECDs were electroswitchable from a colored state (at an applied voltage of –1.5 V) to a bleached state (at an applied voltage of + 1.5 V). Square-wave potential step absorptometry of a UV-unexposed area of: d) PEDOT-MA and e) PProDOT-MA after the photopatterning process. The fi lms were coated onto ITO-coated glass by SCP, and after photopatterning, the transmittance of the unexposed area was monitored at a polymer absorption maximum of 578 nm (d) and 547 nm (e) in 0.1 M LiClO 4 /PC solution. Switching potential range: d) –0.9 V to + 0.6 V vs. Ag wire and e) –0.5 V to + 1.0 V vs. Ag wire; a platinum wire was used as the counter electrode. From left to right, switch times ( ν ): 30 s increments up to 300 s (5 cycles), 20 s increments up to 400 s (10 cycles), 10 s incre-ments for 400 s (20 cycles), then 5 s increments for 200 s (20 cycles).

d)

a)

0 200 400 600 800 1000 12000

10

20

30

40

50

60

70

Time (S)

Tra

nsm

itta

nce

(%

)

ν = 30s ν = 20s ν = 10s ν = 5s

b)

0 200 400 600 800 1000 12000

10

20

30

40

50

60

70

Time (s)

Tra

nsm

itta

nce

(%

)

ν = 30s ν = 20s ν = 10s ν = 5s

e)

c)

Δ T = 45.7%

Δ T = 44.5 %

Δ T = 40.8 %

Δ T = 28.1 %

Δ T = 41.1 %

Δ T = 40.6 %

Δ T = 37.2 %

Δ T = 32.7 %

in ECD. [ 40 ] Therefore, PProDOT-MA could be applied to a high contrast patterned ECD, taking advantage of its purple color that is a combination of red and blue. This could lower the consumption of EC materials, as it requires only one additional color (green EC), and provides a simple fi lm deposition process for the fabrication of a black colored ECD.

The mechanism of EC switching is based on reversible redox reactions, which offer bistability in each state. In EC fi lms, the two states are stable even after removal of bias. As shown in Figure 4 b, the patterned image of the fl exible ECD prepared from PProDOT-MA was maintained after the elec-tricity was turned off. The average absorbance decreases at three wavelengths were less than 10% even after 38 h in the power-off state. This memory effect is important for displaying

© 2011 WILEY-VCH Verlag GAdv. Mater. 2011, 23, 4168–4173

information without consumption of power, thereby conserving the electricity and power delivered to the display. The displayed letter image faded away only when the opposite potential (1.5 V) was applied to the cell to reverse the EC reaction in SPE, [ 41 ] and it reversibly appeared when –1.5 V was applied to the cell at two electrode system. This result suggests that patternable poly(3,4-alkylenedioxythiophene)s are promising for fl exible low power consumption displays, as they show stable patterns with long memory effects.

In summary, methacrylate groups attached to EDOT and ProDOT derivatives were synthesized for solution casting polymerization to afford conductive polymer fi lms on various substrates. The resultant polymer fi lms were directly patterned by UV through a photomask to afford EC patterns. The UV

4171mbH & Co. KGaA, Weinheim wileyonlinelibrary.com

417

www.advmat.dewww.MaterialsViews.com

CO

MM

UN

ICATI

ON

Figure 4 . Optical properties of fabricated devices: a) CIE diagrams of PEDOT-MA and PProDOT-MA fi lms at oxidation and reduction states and b) memory effect of an ECD using a patterned fl exible PProDOT-MA fi lm at different wavelengths (400, 547, 600 nm) over time.

-40 -20 0 20 40

-40

-20

0

20

40

L* = 35

L* = 43

L* = 50

L* = 65

PEDOT-MA (at -1.5 V)

PProDOT-MA (at -1.5 V)

PProDOT-MA (at +1.5 V)

PEDOT-MA (at +1.5 V)

b*

a*

-b*

-a*

yellow

blue

redgreen

a) b)

0 10 20 30 400.0

0.2

0.4

0.6

0.8

1.0

off

(coloration)

Time (hr)

on

Ab

sorb

an

ce (

a.u

.)

400 nm 547 nm 600 nm

unexposed fi lm showed vivid EC properties with large transmit-tance contrasts ( Δ T ). The EC response of the PProDOT-MA fi lm was faster than that of the PEDOT-MA fi lm, possibly due to the larger ring size of the former. The color of patterned PProDOT-MA fi lm at neutral state was purple, while that of PEDOT-MA fi lm was blue, indicating that PProDOT-MA fi lm is promising for high contrast black-colored ECDs. This allowed preparation of high contrast EC patterns on a 7 in. fl exible display, which showed long memory effects to propose an energy saving dis-plays. We believe that the method used to design and synthe-size the solution processable and patternable poly(3,4-alkylene-dioxythiophene)s provides a simple fabrication route to various π -conjugated polymers and their displays.

Experimental Section Synthesis of Methacrylate-Functionalized EDOT-MA and ProDOT-MA :

As shown in Figure S1 (Supporting Information), the monomer of the photopolymerizable conductive polymer, EDOT-MA was synthesized as previously reported. [ 2 ] For the synthesis of ProDOT-MA, a solution of ProDOT-MOH (1 g, 5.0 mmol) in methylene chloride (50 mL) was added to a fl ask equipped with a N 2 purge. After the addition of triethylamine (0.61 g, 6.0 mmol) at 0 ° C, the mixture was stirred for 30 min and then methacryloyl chloride (0.63 g, 6.0 mmol) was added drop-wise for 30 min under an N 2 atmosphere. After 24 h of stirring at room temperature, the resulting mixture was washed with 500 mL of 1 M HCl solution (aq) for neutralization. Then the product was extracted with methylene chloride. The organic layer was washed with water and the organic phase was dried with MgSO 4 . After removal of the solvent, the remaining crude product was isolated by column chromatography (silica gel, hexane/ethylacetate 2:1), yielding ProDOT-MA as a viscous

2 © 2011 WILEY-VCH Verlag wileyonlinelibrary.com

brownish liquid (yield 1.2 g, 89%). 1 H NMR (400 MHz, CDCl 3 , δ ): 6.48 (s, 2H, Th), 6.16–5.57 (m, 2H, C = CH 2 ), 4.06–4.03 (m, 4H, –OCH 2 CH), 3.742 (m, 2H, O = C–OCH 2 –), 1.95 (s, 3H, O = C–OCCH 3 ), 0.95 (s, 3H, C–CH 3 ). FT-IR (neat, cm − 1 ): 2959, 1716, 1637, 1482, 1451, 1425, 1376, 1299, 1183, 1062, 1015, 945, 920, 847. MS ( m / z ): [M] + calcd. 268.08; found, 268.07. Elemental analysis: calcd. for C 13 H 16 O 4 S, C = 58.2, H = 6.0, O = 23.8, S = 12.0; found, C = 57.5, H = 6.0, O = 24.6, S = 11.9%.

Preparation of Monomer Solution and Solution Casting Polymerization (SCP) : Fe(III) tosylate (5.4 g) was dissolved in 8 g of alcohol and stirred for 1 h at room temperature. To this solution, 0.31 g of pyridine was added and stirred for 1 h and fi ltered by hydrophilic syringe fi lter. The proper amount of monomer was added to this oxidant solution and stirred for 10 min. The coating solution consisted of 43 wt% of the mixture solution of pyridine, Fe(III) tosylate, monomer, and 57 wt% of butanol. The molar ratio of pyridine: Fe(III) tosylate: monomer was fi xed as 1.1:2.25:1. Then the above solution was spin-coated on substrates, controlling the spinning speed to achieve the desired fi lm thickness. After the coating process, the solution-coated substrate was heated at 60–80 ° C to trigger oxidative polymerization and so afford a colored polymeric fi lm on the substrate. After cooling to room temperature, the conductive polymer-coated substrate was washed with isopropyl alcohol to remove the residual oxidant, low molecular weight oligomers, and impurities. After washing the substrate, the fi lm was dried under N 2 fl ow and used for patterning.

Patterning of Conductive Polymer : Photopatterning was carried out using a UV light source (INNO Cure 100N, 22.3 mW cm − 2 , Lichzen Co., Ltd) and a photomask coated with Cr on quartz. The PEDOT-MA and PProDOT-MA coated ITO glass (or fi lm) by the SCP was coated with a solution of Irgacure 1173 (0.5 wt%) in an anhydrous organic solvent (ethanol or diethyl ether) and was then placed under the photomask. The conductive polymer fi lm was irradiated under an N 2 atmosphere, and the residual initiator was washed with fresh isopropyl alcohol. The paterned fi lm was dried under N 2 fl ow.

Fabrication of ECDs : A window-type device was constructed using the patterned conductive substrate coated with PEDOT-MA or PProDOT-MA

GmbH & Co. KGaA, Weinheim Adv. Mater. 2011, 23, 4168–4173

www.advmat.dewww.MaterialsViews.com

CO

MM

UN

ICATIO

N

as a working electrode and bare conductive electrode as a counter electrode. The solid polymer electrolyte (SPE) solution was prepared by mixing MPEGM (0.3 g), PEGDMe (0.6 g), TATT (0.072 g), Darocure 1173 (0.06 g), Irgacure 784 (0.003 g), and LiTFS (0.06 g) according to a method reported in the literature. [ 42 ] The electrolyte was injected into a sandwiched device with double-sided tape as a spacer, and the device was sealed with epoxy sealant on the outer edges.

Supporting Information Supporting Information is available from the Wiley Online Library or from the author.

Acknowledgements The authors acknowledge fi nancial support from a National Research Foundation (NRF) grant funded by the Korean government (MEST) through the Active Polymer Center for Pattern Integration (R11-2007-050-00000-0).

Received: May 23, 2011 Revised: June 29, 2011

Published online: August 12, 2011

[ 1 ] P. M. Beaujuge , J. R. Reynolds , Chem. Rev. 2010 , 110 , 268 . [ 2 ] P. M. S. Monk , R. J. Mortimer , D. R. Rosseinsky , Electrochromism

and Electrochromic Devices , Cambridge University Press, Cambridge, UK 2007 .

[ 3 ] A. L. Dyer , J. R. Reynolds , in Handbook of Conducting Polymer , 3 rd ed. , (Eds: T. Skotheim , J. R. Reynolds ), CRC Press, Taylor & Francis Group , Boca Raton, FL 2007, Vol. 1 , Chapter 20 .

[ 4 ] A. L. Dyer , M. R. Craig , J. E. Babiarz , K. Kiyak , J. R. Reynolds , Macro-molecules 2010 , 43 , 4460 .

[ 5 ] A. Durmus , G. E. Gunbas , P. Camurlu , L. Toppare , Chem. Commun. 2007 , 31 , 3246 .

[ 6 ] G. E. Gunbas , A. Durmus , L. Toppare , Adv. Mater. 2008 , 20 , 691 . [ 7 ] B. D. Reeves , C. R. Grenier , A. A. Argun , A. Cirpan , T. D. McCarley ,

J. R. Reynolds , Macromolecules 2004 , 37 , 7559 . [ 8 ] M. Li , Y. Sheynin , A. Patra , M. Bendikov , Chem. Mater. 2009 , 21 ,

2482 . [ 9 ] A. Balan , G. Gunbas , A. Durmus , L. Toppare , Chem. Mater. 2008 ,

20 , 7510 . [ 10 ] P. M. Beaujuge , S. Ellinger , J. R. Reynolds , Nat. Mater. 2008 , 7 , 795 . [ 11 ] M. lcli , M. Pamuk , F. Algi , A. M. Önal , A. Cihaner , Chem. Mater.

2010 , 22 , 4034 . [ 12 ] A. F. Diaz , J. I. Castillo , J. A. Logan , W.-Y. Lee , J. Electroanal. Chem.

1981 , 129 , 115 . [ 13 ] A. Cihaner , A. M. Önal , J. Electroanal. Chem. 2007 , 601 , 68 . [ 14 ] M. Bendikov , A. Patra , Y. H. Wijsboom , S. S. Zade , M. Li , Y. Sheynin ,

G. Leitus , J. Am. Chem. Soc. 2008 , 130 , 6734 .

© 2011 WILEY-VCH Verlag GmAdv. Mater. 2011, 23, 4168–4173

[ 15 ] Y. H. Wijsboom , A. Patra , S. S. Zade , Y. Sheynin , M. Li , L. J. W. Shimon , M. Bendikov , Angew. Chem. Int. Ed. 2009 , 48 , 5443 .

[ 16 ] M. Li , A. Patra , Y. Sheynin , M. Bendikov , Adv. Mater. 2009 , 21 , 1707 . [ 17 ] M. Dietrich , J. Heinze , G. Heywang , F. Jonas , J. Electroanal. Chem.

1994 , 369 , 87 . [ 18 ] B. D. Reeves , C. R. G. Grenier , A. A. Argun , A. Cirpan , T. D. McCarley ,

J. R. Reynolds , Macromolecules 2004 , 37 , 7559 . [ 19 ] P. Shi , C. M. Amb , E. P. Knott , E. J. Thompson , D. Y. Liu , J. Mei ,

A. L. Dyer , J. R. Reynolds , Adv. Mater. 2010 , 22 , 4949 . [ 20 ] C. M. Amb , A. L. Dyer , J. R. Reynolds , Chem. Mater. 2011 , 23 , 397. [ 21 ] P. M. Beaujuge , C. M. Amb , J. R. Reynolds , Adv. Mater. 2010 , 22 ,

5383 . [ 22 ] A. A. Argun , M. Berard , P. H. Aubert , J. R. Reynolds , Adv. Mater.

2005 , 17 , 422 . [ 23 ] A. Vlad , C. A. Dutu , P. Guillet , P. Jedrasik , C.-A. Fustin , U. S. Dervall ,

J.-F. Gohy , S. Melinte , Nano Lett. 2009 , 9 , 2838 . [ 24 ] T. S. Hansen , K. West , O. Hassager , N. B. Larsen , Adv. Mater. 2007 ,

19 , 3261 . [ 25 ] K. S. Schanze , T. S. Bergstedt , B. T. Hauser , Adv. Mater. 1996 , 8 ,

531 . [ 26 ] K. S. Schanze , T. S. Bergstedt , B. T. Hauser , C. S. P. Cavalaheiro ,

Langmuir 2000 , 16 , 795 . [ 27 ] C. B. Nielsen , A. Angerhofer , K. A. Abboud , J. R. Reynolds , J. Am.

Chem. Soc. 2008 , 130 , 9734 . [ 28 ] A. L. Dyer , M. R. Craig , J. E. Babiarz , K. Kiyak , J. R. Reynolds , Macro-

molecules 2010 , 43 , 4460 . [ 29 ] N. D. Robinson , M. Berggren , in Handbook of Conducting Polymers ,

Third ed. , (Eds: T. A. Skotheim , J. R. Reynolds ), CRC Press , Boca Raton, FL 2007 , Vol. 1 .

[ 30 ] G. H. Shim , M. G. Han , J. C. Sharp-Norton , S. E. Creager , S. H. Foulger , J. Mater. Chem. 2008 , 18 , 594 .

[ 31 ] J. Kim , J. You , E. Kim , Macromolecules 2010 , 43 , 2322 . [ 32 ] B. Winther-Jensen , K. West , Macromolecules 2004 , 37 , 4538 . [ 33 ] B. Winther-Jensen , D. W. Breiby , K. West , Synth. Met. 2005 , 152 , 1 . [ 34 ] D. M. Welsh , A. Kumar , M. C. Morvant , J. R. Reynolds , Synth. Met.

1999 , 102 , 967 . [ 35 ] C. L. Gaupp , D. M. Welsh , R. D. Rauh , J. R. Reynolds , Chem. Mater.

2002 , 14 , 3964 . [ 36 ] M. L. Hitchman , J. Electroanal. Chem. 1977 , 85 , 135 . [ 37 ] W. C. Dautremont-Smith , Displays 1 1982 , 3 . [ 38 ] CIE Colorimetry (Offi cial Recommendations of the International

Commission on Illumination); CIE Publication No. 15 , CIE: Paris 1971 .

[ 39 ] B. C. Thompson , P. Schottland , K. Zong , J. R. Reynolds , Chem. Mater. 2000 , 12 , 1563 .

[ 40 ] E. Unur , P. M. Beaujuge , S. Ellinger , J. Jung , J. R. Reynolds , Chem. Mater. 2009 , 21 , 5145 .

[ 41 ] a) F. M. Gray , Solid Polymer Electrolytes: Fundamentals and Techno-logical Applications , Wiley-VCH , Weinheim 1991 ; b) E. Kim , S. Jung , Chem. Mater. 2005 , 17 , 6381 .

[ 42 ] T. Kwon , B. D. Sarwade , Y. Kim , J. Yoo , E. Kim , Mol. Cryst. Liq. Cryst. 2008 , 486 , 101 .

4173bH & Co. KGaA, Weinheim wileyonlinelibrary.com