LABORATOIRE DE PHYSIQUE DES LASERS Photonique Organique et Nanostructures Support de thèse : ANR OLD-TEA Direction de thèse : Alexis Fischer et Azzedine

LABORATOIRE DE PHYSIQUE DES LASERS

Photonique Organique et Photonique Organique et NanostructuresNanostructures

Support de thèse : ANR OLD-TEADirection de thèse : Alexis Fischer et Azzedine Boudrioua Encadrement : Mahmoud ChakarounAssistance technologique Jeanne Solard

Collaboration: Chii-Chang Chen ,National Central University , Taiwan

Investigation of photonic properties of Investigation of photonic properties of self organized nanoparticles self organized nanoparticles

monolayers : application to photonic monolayers : application to photonic crystal cavities and patterned organic crystal cavities and patterned organic

light emitting diodeslight emitting diodesGetachew T. AYENEW

PhD defence : July 8th, 2014

Thank you mister president.My name is Ayenew Getachew, and I'm going to present you my work entitled Photonic properties....This work was done under the supervision of....Prof Fischer and Boudrioua as thesis director in collaboration with Prof. Chii-chang Chen from NCU Taïwan

Outline

1. Introduction► Context

► State of the art

► Our approach

2. Photonic properties of monolayer of opals and inverse-opals► Numerical study of photonic band gaps

► Numerical study of microcavities

► Experimental approach of characterizing monolayer of opals

3. Nanoparticle based 2D patterning of OLED► 2D pattering of surfaces

► 2D patterning of OLEDs

4. Conclusion and perspectives

2

My talk is divided in two main section :I will first introduce my work and its context. In the second part I will present investigations on the photonic properties of nanostructures based onself organized nanoparticules.In the third chapter I will presetnn experimental results on nanoparticle based 2dimensional patterning of OLEDI will finish with a conclusion and perspectives.

3

1D Vertical confinement

Top down Bottom up

Small Mode

volume

High Q

Extended cavity

1. Introduction

Context :ANR OLD-TEA 2010-2013

Axe 1

Organic Laser Diode : A Threshold-Less Experimental Approach

Axe 2

2D lateral confinement

Photonic Crystal Opals - Inverse Opals

Low threshold organic diode laser

2D DFB lasers

Light extraction in OLED

Potential Applications

The context of this work deals with the quest of the organic laser diode which has not been demonstrated so far. The Organic Photonic and Nanostructures group adress this quest with a low-threshold laser approach. The group is involved in embedding OLED in different type of microcavities. This requires high Q and or low mode volume laser cavities so as to lower the laser threshold at the level of the highest current density in OLED.Axe 1 deals with Fabry-perot type of microcavities, whereas axe 2 consider photonic crystal nanocavities. In a previous thesis done by Franocis Gorudon very low laser threshold were obtained with defect cavity in photonic crystal realize by a top-down approach with an e-beam and ICP etching.The goal of my thesis is to investigate if opals and inverse opals can be used in a bottom up approach to design and fabricate photonic crystal

► Photonic properties of monolayer of nanoparticles and microcavities

► New patterning technique using nanoparticles 4

1. Introduction

Objectives of the study

Self-organized Nanoparticles

Photonic crystals OLED Nanostructuration

Photonic crystal laserwith defect microcavity

2D-DFB OLD Light extraction in OLED


► Making nanostructures using nanoparticles 5

1. Introduction






6

State of the artPolymeric solid-state dye lasers resonator

Shi et al. Appl. Phys. Lett. 98, 093304 (2011)

Random lasingDye doped photonic crystal

Kim et al Chem. Mater., 2009, 21 (20), pp 4993–4999 Murai et al, Chemistry LettersVol. 39 (2010) , No. 6 p.532

porous photonic film enhanced stimulated emission Lasing by randomly dispersing nanoparticles into a gain material• multiple scattering

highly-efficient low threshold laser

Emission spectra of the resonator cavity below and above lasing threshold

2. Photonic properties of monolayer of opals and inverse-opals

►General objective► Optimal design of planar photonic

crystal using nanoparticles ?► Microcavity ?

►Methodology

► Investigate numerically photonic band gaps in monolayer of dielectric spheres

► Investigate numerically quality factors of microcavities

► Experimental investigation of in-Plane propagation 7

glass

General objective/Methodology

0.2 0.3 0.4 0.5

0.0

0.2

0.4

0.6

0.8

1.0

Transmission spectrum

Cavity response

Normalized Frequency(a/)

Tra

ns

mis

sio

n

0

20

40

60

80

100

Inte

ns

ity

(a.u

.)


Opal without substrate

8

Structures

glass

air

air

air

2r

air

air r

air

glass

a

Inverse opal without substrate

Opal with substrate Inverse opal with substrate

r

a

a = period r = radius

2. Numerical study of photonic band gaps

Control parameters


ra

9

2__

33

4

___

__

a

r

cellun ito fV o lum

sphereso fV o lum eff ce llun itinspheres

Refractive index (n)• n of spheres in opals• n of infiltrated material in inverse-

opals

Compactness of spheres , r/a ratio ( for n = 2.5, anatase TiO2)

• r/a=0.5, compact spheres• r/a < 0.5 non- compact spheres• r/a ratio determines the filling factor

(ff)

Filling factor

Effective refractive indexneffective=√ϵ effective=√ff spheres ϵ spheres+(1−ff spheres)ϵ voidsUnit cell

10

Parameters

► Direction of propagation of the incident field with respect to the crystal

► M ( TE, TM polarisations)

► ( TE, TM polarisations)► Symetries and rotation


K

M K

► Boundary conditions► Perfectly matched layer (PML)► Periodic

11

2.1 Introduction to simulation Simulation condition► 3D finite-difference time-domain(3D-FDTD) method


Top view

Cross section

► Photonic band gap ► Gap maps

12

Photonic band gap(PBG) and construction of gap maps

PBG

n=3

n=2.1PBG

n=1.5

Photonic gapmap

Transmission spectra

n=2.2


M direction , TE polarization

direction , TE polarization

(intersection) 'complete' bandgap

► Gap maps►Different

polarizations►TE►TM

►Different directions of propagation►M►K

13

Photonic band gap(PBG) and construction of gap maps


PBG

14

Inverse-opals without substrate

Region for TE polarization

r/a=0.5

TiO2(n=2.5)

► PBG exists for a wide range of refractive indices► PBG exists for a wide range of compactnesses► For n=2.5, Largest gap to mid-gap ratio for

r/a=0.4, (TE)

Δf

fwidth of PBG = gap-mid-gap ratio= Δf/f


n=2.5

r/a

► Opals without substrate exhibit PBGs for different compactness

► PBG appears narrower15

n=2.5, TiO2

Opals without substrate


0.3 0.4 0.5 0.6 0.70.25

0.30

0.35

0.40

0.45

0.50r/

a


► First conclusion- monolayer of inverse opal offers larger gap-to-midgap ratio

16

0.2 0.3 0.4 0.5 0.6 0.7

0.000.330.660.99

0.0000.0550.1100.165

0.000.330.660.990.000.080.160.24

0.0000.0860.1720.258

0.000.330.660.99

0.0000.0610.1220.183

Tra

ns

mis

sio

n

Normalized frequency (a/)

r/a = 0.25

r/a = 0.29

r/a = 0.33

r/a = 0.37

r/a = 0.41

r/a = 0.45

r/a = 0.5

0.2 0.3 0.4 0.5 0.6

0.000.330.660.99

0.0000.0250.0500.0750.1000.00

0.330.660.990.000.330.660.990.000.330.660.990.000.330.660.990.000.330.660.99

Normalized Frequency (a)

r/a = 0.25

r/a = 0.29

r/a = 0.33

r/a = 0.37

Tra

ns

mis

sio

n

r/a = 0.41

r/a = 0.45

r/a = 0.5

0.25 0.30 0.35 0.40 0.45 0.50

0.05

0.10

0.15

0.20

0.25

0.30

f/f

r/a

GMTE width-opal GMTE width-inverse opal

гM-TE гM-TE

Opal or inverse-opal ?


Opals Inverse-Opals

► Losses to glass substrate► No PBG for low ref. index materials► Higher refractive index materials

required17

r/a=0.5

► PBG observed with non-compact spheres

► Overlap of TE mode for non-compact spheres

Substrate effect: inverse-opal with substrate


TiO2(n=2.5)

TiO2(n=2.5)

r/a

0.3 0.4 0.5 0.6 0.7 0.8 0.90.25

0.30

0.35

0.40

0.45

0.50

r/a


► Losses to glass substrate as r/a is lower► More compact spheres favorable

18

n=2.5

Lossy region

glass

Substrate effect : opal with substrate


► Opals: as the spheres are more compact neff increases less loss ► Inverse opals: as the spheres are more compact neff decreases more

loss 19

n=2.5

0.2 0.3 0.4 0.5 0.6 0.7

0.000.330.660.990.000.330.660.990.000.330.660.990.000.330.660.990.000.330.660.990.000.250.500.750.000.250.500.75

Normalized frequency (a/)

Tra

nsm

issi

on

r/a = 0.5

r/a = 0.45

r/a = 0.41

r/a = 0.37

r/a = 0.33

r/a = 0.29

r/a = 0.25

n=2.5

0.2 0.3 0.4 0.5 0.6 0.7 0.8

0.000.330.660.990.000.250.500.75

0.000.280.560.840.000.330.660.990.000.330.660.990.000.330.660.990.000.330.660.99

Normalized Frequency (a)

r/a = 0.5

r/a = 0.45

r/a = 0.41

r/a = 0.37

r/a = 0.33

r/a = 0.29

r/a = 0.25

Tra

nsm

issi

on

Substrate effect : effect of compactness on losses


compacthigh neff

non-compactlow neff

Less compactMore losses

compactlow neff

non-compact high neff

Morecompact

More losseslarger filling factor

smaller filling factor

Opals Inverse-opals

air

opal, r/a = 0.5

glass

zy

x

glass

air

opal, r/a = 0.31

glass

air

inverse opal, r/a = 0.31

glass

air

opal, r/a = 0.31

20

Substrate effect : effect of compactness on losses


Compact opalshigh neff

Non compactlow neff

More losses

compactlow neff

Non compactInverse-opal

high neff

More losses



►Methodology




glass


0.2 0.3 0.4 0.5

0.0

0.2

0.4

0.6

0.8

1.0


Cavity response


Tra

ns

mis

sio

n

0

20

40

60

80

100

Inte

ns

ity

(a.u

.)


► Investigation with respect to► Various cavity geometries► The r/a ratio► with and without substrate (effect of the losses)

H1 L5L3H2

Microcavities

► Fixed refractive index n= 2.5► Defects in the periodicity

monitor source

2. Numerical study of microcavities

22

► Without substrate:► Cavity resonance in the

PBG

► With substrate► Significant resonant peaks

observed for non-compact arrangement

Microcavities in inverse-opals


23

► Quality factor increases when r/a < 0.40► The presence of glass substrate reduces the quality factor► The maximum of the Q-factor is obtained for 0.3 < r/a < 0.35

24

Microcavities in inverse-opals with and without


0.1 0.2 0.3 0.4-5.00E+012

0.00E+000

5.00E+012

1.00E+013

1.50E+013

2.00E+013

2.50E+013

3.00E+013

3.50E+013

Inte

ns

ity

(a

.u.)

n=3,2 air resonance r/a=0,5 n=3,2 glass resonance r/a=0,5n=4, glass r/a=0,5

Normalized wavelength ( a/)

Inte

ns

ity

(a

.u.)

0.00E+000

2.00E+009

4.00E+009

6.00E+009

8.00E+009

1.00E+010

25

H2

Higher refractive index values needed in opals to achieve a resonance: (n~4 realistic?)

► The inverse-opal arrangement is more favorable to microcavities

Microcavities in opals


n=4

n=3.2

n=3.2



►Methodology




glass


0.2 0.3 0.4 0.5

0.0

0.2

0.4

0.6

0.8

1.0


Cavity response


Tra

ns

mis

sio

n

0

20

40

60

80

100

Inte

ns

ity

(a.u

.)


► Objectives► Measure of the In-Plane

transmission spectra as a function of

► Polarization (TE, TM)

► Crystal direction (M, K)

► Problem ► Arrangement of spheres –

presence of multiple domains► Several directions are probed at

the same time

► Method► Fabrication of a single domain

monolayers ?► Characterization of single

domain ?27

2. Towards experimental study of in-plane propagation in opal monolayers

Problem and method

transmittedtransmitted

Direction of propagation

Light ΓM

ΓK

Reference

waveguide

nanoparticlesmicro-

hexagon

► Single domain fabrication► Fabrication of micro-hexagons

► force nanoparticles organizaton in ordered manner

► Orientation of hexagons to fixe the direction of propagation

► Dimension calculated for given nanoparticle diameter

► Single domain characterization► Waveguides

• Polymer waveguide on a glass substrate

• In- and out-coupling• Single domain probing

2. Towards experimental study of in-plane propagation in opal monolayers Approach: single domain samples and characterization

28

29

10µm

2. Towards experimental study of in-plane propagation of opal monolayers

Preliminary experimental results: Fabricated waveguides

micro-hexagon

waveguide

► Clearly defined waveguide structure and micro-hexagon

► Different orientations of the micro-hexagons

► The diameter of the microneedle is too large as compared to the size of the micro-hexagon► Nanoparticles not in the target area

30

► 1.5µm spheres used for optimization of the process


Preliminary experimental results: Deposition of nanoparticles

31


Conclusion and perspectives on experiments part 1

► Conclusion► Method of micro-hexagon

promising to make single-domain monolayers

► Waveguides can enable in- and out- coupling from the nanoparticles

► Deposition by micro-needles not successful

► Perspective► Deposition by microfluidic channels

– easy to deliver the nanoparticle solution to micro-hexagon

Adv. Funct. Mater., Vol.19, 1247–1253(2009)

32

Conclusion and perspectives part 1

► Numerical investigation on opals and Inverse opals► Photonics bandgap exist in Opals and Inverse-Opals ► The inverse-opal structure exhibits larger PBG than the

opal structure► Non-compact inverse-opal structure has highest Q-factor ► Opal micro-cavities require high refractive index to have

cavity resonances► Experimental study of propagation in opals

► In-plane propagation experiment of single domain opals►Micro-hexagons►Waveguide

► Perspectives :► Simulation: Mode volume calculation► Experiment: nanoparticle self-organization by micro-

channels



► Making nanostructures using nanoparticles 33

3. OLED Nanostruturation






► Objectives► Patterning OLEDs

► Light extraction : requires period of lattice ~1-2.5 µm.

► 2D DFB laser : requires period of lattice < 500 nm.

► Issues► E-beam

► Time consuming

► Expensive

► Method► Principle of photolithography using nanoparticles► Simulations► Experiments► Analysis

34

3. OLED Nanostruturation


(Journal of Nanoscience, Volume 2014 (2014))

35

State of the art: Microsphere based patterning and OLED patterning

3. 2D nanostructuration of OLED

► Laser ablation

Optical Engineering 491, 014201

Laser exposure

► Micro-lens focusing

Nanoscale Res Lett., Vol. 3, 123–127(2008)

OPTICS EXPRESS / 2005 / Vol. 13, No. 5

► Electron-beam lithography

► Nanosphere lithography Nano Letters, 2002, 2 (4), pp 333–335

36

Our approach : self-organized nanoparticle photolithography


Monolayer of nanoparticles

UV

development

► Nanoparticle based reusable photolithographic mask► Photomask made with

nanoparticles

► Light exposure

► Development and reproducing close-packed microsphere pattern on photoresist

► Process advantages• Reusable mask

• Simple

• Cheap

• Large area

to OLED processing

patternedphotoresist

patternedOLED

37

Experiment : The process


► Process parameters► Spin coating: 6000rpm► Soft bake: @100°C, 90 sec.► UV exposure: @405nm,

0.9sec► Developmenet: 9 sec

► Materials used► Size and type of microspheres:► SiO2- 800nm, 1µm, 1.25µm,

1.53µm, 1.68µm, 1.96µm, 2.34µm

► Polystyrene- 1.68µm► Photoresist, Az-1505► Developer- MF-319

► Large area microsphere thin-film on the substrate

38

2.5cm

1.7cm

► SEM: Periodically arranged monolayer of micro nanoparticles – presence of defects in the crystal

Results: photomask made with self-organized nanoparticles


1µmMade by 2.34 µmsize microspheres microspheres mask

Result: Patterned photoresist

39

►Homogenous pattern made by self-organized nanoparticles

photolithography


On the same sample

40

Results: 2 kinds of patterns on the same sample !

UV

half of the period of the monolayer mask

the period of the monolayer mask reproduced


► Period of lattice less than 750nm

► hole diameter less than 405 nm

► Reduced-Period not observed for microsphere sizes of 800nm and 1μm

41

Results: Different size of micro nanoparticles

► Different size of microspheres: 800nm, 1µm, 1.25µm, 1.53µm, 1.68µm, 1.96µm, 2.34µm

► Two contact modes of the mask aligner: hard contact and soft contact


42

Micro-ball Lens effect Phase-mask effect

Simulation: 2 kinds of patterns

► Hard-contact and soft-contact modes of the mask

aligner

period of pattern = ½ * (period of microspheres)

period of pattern = period of microspheres


► Micro ball-lens► focal length► Numerical aperture

max 43

Phase-mask► Fundamental low of

grating► Transmitted angle 1

Analysis : self-oganized microparticles


The array of self-organized micro nanoparticles is both a collection of ball-lenses and a 2D-phase mask

1

44

Red OLED

Green OLED


glassITO

patterned photoresist

Micro-OLEDS: Organic hetero-structures - band diagram

45


Micro-OLEDs: Images

► Micro-OLED sizes = 1.27µm

► Method compatible with OLED operation

46


Micro-OLEDs: Spectra

► Emission under normal incidence► Small spectral modification of

emitted light as compared to large area OLED

► Perspectives► Measurements for other angles of

emission► Edge emission► Smaller period of pattern

glass

► Conclusion► Cheap, simple method to pattern 2D surfaces on large area► The patterning method is compatible with OLED deposition

47

Conclusion and perspective part 2

► Perspective► Characterization of the emission

• Measurement of the emission diagram• Edge emission

► Towards 2D-DFB laser :• Smaller lattices : 200-300 nm• Lower exposure wavelength (<405nm) to increase the

resolution of the nanoparticles lithography process• Deep UV (DUV) lithography and DUV photoresist

► Use negative photoresist to make periodic pattern of micro nano-pillars


48

Photonic properties of opal and inverse-opal monolayers► Monolayers of O and I-O do exhibit photonic bandgap► The inverse-opal structure exhibits larger PBG► Non-compact (r/a=0.4) TiO2 inverse-opals exhibit the largest PBG► Highest Q-factor is obtained in inverse –opals for r/a ratio ~ 0.32.► Opal micro-cavities require high refractive index to exhibits cavity

resonances

► Nanoparticle photolithography► Monolayers of nanoparticles used to make periodic pattern on

photoresist• Lattice down to 750 nm• Holes down to 450 nm

► Array of micro-OLEDs (size = 1.27µm) fabricated ► Perspectives :

• 2D-DFB organic laser fabrication requires Deep-UV photolithography (193 nm)• Applications of the nanoparticle photolithography technique : Patterning

surface with metal (SERS, Molecules detection, OLED efficiency increases via Surface Enhanced Plasmon Resonance.

4. General Conclusion

Thank you for your attention

49

► Conclusion ► Structures without substrate exhibit PBGs for wide range of

refractive indices and compactness► Generally inverse opals have larger photonic bandgap

width► Structures with substrate have losses for lower refractive index

materials► Considering n=2.5, lower compactness in inverse opals

and higher compactness in opals result in lower losses to glass substrate

► Inverse-opal with lower compactness on glass substrate seems to be a good compromise between the losses and the width of PBG

► Thus microcavities designed in non-compact sphere inverse-opals are expected to have better confinement► Calculation of quality factors is necessary to optimize the

optimum r/a value for a given refractive index50

Conclusion


► Highest Q-factor(~300) obtained for non-compact spheres in inverse-opals.

► With a glass substrate the Q factor is limited to Q~200

► Glass substrate reduces Q-factors

► Micro-cavities in opals require refractive index larger than n=3.2 which is hardly feasible

► The literature presents much higher Q-factor in conventional Phc Slabs.

51

Conclusion on Microcavities


52

sample


Preliminary experimental results: Deposition of nanoparticles

Micro-needle and micro-syringe

53

► Light extraction

(lattice ~ 1-2.5 µm)

► Light extraction

► DFB lasing ► DFB lasing

Deep UV litho.Smaller lattice(<500 nm)

Etching ITO

Etching glass substrate

Etching glass substrate

Conclusion and perspectives


54

Conferences and papers

► Papers► Getachew T. Ayenew, Alexis P.A. Fischer, Chia-Hua Chan, Chii-Chang Chen, Mahmoud Chakaroun, Jeanne Solard, Azzedine Boudrioua,”Two-dimensional patterning of organic light

emitting diode based on self-organized nanoparticles photolithography” Submitted to optics Express (may 2014)

► F. Gourdon, A.P.A. Fischer, M. Chakaroun, G. Ayenew and Azzedine Boudrioua “Study of the organic layer thickness effect in a hybrid photonic crystal L3 nanocavity under optical

pumping”, Accepted in Journal of Nanophotonics, 5 may 2014

► Min Won Lee, Siegfried Chicot, Chii-Chang Chen, Mahmoud Chakaroun, Getachew Ayenew, Alexis Fischer, and Azzedine Boudrioua, Study of the Light Coupling Efficiency of OLEDs Using

a Nanostructured Glass Substrate , Journal of Nanoscience, Volume 2014 (2014)

► Getachew T. Ayenew ; Mahmoud Chakaroun ; Nathalie Fabre ; Jean Solard ; Alexis Fischer ; Chii-Chang Chen ; Azzedine Boudrioua ; Chia-Hua Chan Photonic properties

of two-dimensional photonic crystals based on monolayer of dielectric microspheres , Proc. SPIE 8424, Nanophotonics IV, 84242X (April 30, 2012);

► Sokha Khiev, Lionel Derue, Getachew Ayenew, Hussein Medlej, Ross Brown, Laurent Rubatat, Roger C. Hiorns, Guillaume Wantz and Christine Dagron-

Lartigau,"Enhanced thermal stability of organic solar cells byusing photolinkable end-capped polythiophenes", Polym. Chem., 2013,volume 4, 4145-4150 (2013)

► Conference

► Getachew T. Ayenew, Mahmoud Chakaroun, Nathalie Fabre, Jeanne Solard, Alexis Fischer, Azzedine Boudrioua, Chii-Chang Chen, Chia-Hua Chan, « Photonic properties

of two-dimensional photonic crystals based on monolayer of dielectric nanospheres » Poster SPIE 16 - 19 April 2012, Square Brussels Meeting Centre Brussels, Belgium.

► Getachew T. Ayenew, Anthony Coens, Mahmoud Chakaroun, Jean Solard, Alexis P. A. Fischer, Chii-Chang Chen, Chia-Hua Chan, Azzedine Boudrioua, Micro-Oled

fabricated by microsphere based lithography, Optique Paris 13, 8 au 11 juillet 2013, Villetaneuse, Présentation Orale.

► Getachew T. Ayenew, Anthony Coens, Mahmoud Chakaroun, Jeanne Solard, Alexis P. A. Fischer, Chii-Chang Chen, Chia-Hua Chan, Azzedine Boudrioua, Micro-OLED

fabricated by microsphere based photolithography, JNRDM 2013, Journées National du Réseau Doctoral en Micro-Nanotechnologies, 10-12 juin 2013, Minatec Phelma,

Grenoble, Poster

30 à 50%

Analyse du problème de l'émission lumineuse

La structure OLED• Interfaces

– ITO / Verre

– Verre /air

Impact sur l'extraction lumineuse• Réflexions aux interfaces :

– 0,8%<R ITO/Verre <19%

– R Verre/air 4%

• Angles limites : lim = Arcsin(n2/n1)

• Réflexion totale interne (TIR)

• Modes guidés dans le verre : 30%

• Modes guidées dans l'ITO : 50%

Taux de couplage : 15 à 20 %

Aluminium

Organiquen=1,7

n=1,8 à 2,2

n=1,5

Verre

2

1

lim

TIR

50 à 30%

Modes guidés

Modes guidés

TIRITO

2

lim

Lumière extraite15% à 20%

R=(n1−n2

n1+n2)2

Impact des angles limites

A partir de la loi de Descartes• n2sin() = n1sin()

• Angles limites : lim = Arcsin(n2/n1)

• ITO/verre : 43°lim<56°

• Verre/Air : lim 42°

• ITO/air : 27°lim<33° (limpour n=2)

• Au delà de l'angle limite il y a réflexion totale interne (TIR) (onde guidée)

Taux de couplage• Ce qui est transmis : T() r2 sind• T() transmittance en fonction de l'angle

• Couplage externe ITO/Air : 15 %

Transmission au delà des angles limites?• Modification de la géométrie grâce aux

nanoparticules ?

lim

=5

6°

lim

=42

°

Cône d'émission ITO /verre

Cône d'émission verre/air

lim

=30°

Cône d'émission ITO/air

57

Organic compounds for OLED

Standard chemical products

Alq3; tris(8-hydroxyquinolinato)aluminum;copper

phthalocyanines

4,4'-Bis(2,2-diphenylvinyl)-1,1'-biphenyl

2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline/Bathocuproine

N,N’-Di(naphthalen-1-yl)-N,N’-diphenyl-benzidine

Organic semiconductors

Photonique Organique

DFB lasing


DFB lasing


Q-factor , mode volume


cav=03Q

42V eff

( n)

3

F P=3Q

42V eff

( n)

3

Q=−ω(t−t 0)

( ln (U ( t )

U ( t0)))

Finite difference


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LABORATOIRE DE PHYSIQUE DES LASERS Photonique Organique et Nanostructures Support de thèse : ANR OLD-TEA Direction de thèse : Alexis Fischer et Azzedine