Effects Of Bending On The Optoelectronic Properties And Failure Mechanism In Organic Photovoltaics

Effects Of  Bending On The Optoelectronic Properties And Failure Mechanism In Organic Photovoltaics.

ABSTRACT

This research investigates the effects of bending on the electrical, optical, structural and mechanical properties of flexible organic photovoltaic (OPV) cells.

Bulk heterojunction organic solar cells were fabricated on Polyethylene terephthalate (PET) substrates using Poly-3-hexylthiophene: [6, 6]-phenyl-C61-butyric acid methyl ester (P3HT: PCBM) as the active layer and Poly (3, 4-ethylenedioxythiophene) Polystyrenesulfonate (PEDOT: PSS) as the hole injection layer.

All the organic layers were deposited by spin coating while the Al cathode was vacuum thermally evaporated.

The Indium Tin Oxide (ITO) anode has an average optical transmittance of 85% in the visible spectrum, a sheet resistivity of 60 ohms per square and an average surface roughness of 3nm.

The relationship between the optoelectronic performance of the various device layers and the applied mechanical strains has been analyzed.

The effects of stress and strain on the current-voltage characteristics of the device and its failure were modeled using the Abaqus software.

TABLE OF CONTENT

ABSTRACT …… iii
DEDICATION ……… iv
ACKNOWLEDGEMENT ………. v
TABLE OF CONTENT ….. vi
LIST OF FIGURES ……… ix
LIST OF TABLES … xii

CHAPTER ONE  INTRODUCTION

1.1 Introduction ……. 1
1.2 The Solar Cell …. 1
1.2.1 Inorganic Solar Cell Limitations 3
1.3 Organic Electronics ….. 4
1.4 Photovoltaic Energy Conversion …. 5
1.4 The Make Up of a Photovoltaic Cell …. 6
1.5 Problem Statement/ Hypothesis … 7
1.6 Scope of Work ….. 8
1.7 Arrangement of Work 8

CHAPTER TWO .

December 9, 2011 DECEMBER,2011 ASARE, Joseph |Dept. of Theoretical Physics (AUST) vii

LITERATURE REVIEW

2.1 Introduction …. 9
2.2 Background …………. 9
2.2.1 The Bulk Heterojunction … 11
2.3 Plasticity ……….. 13
2.3.1 Plasticity in Solar Cell Manufacturing … 14
2.4 The Electrical Interactions at the Organic Solar Cell Interface …… 14
2.5 Theory ….. 17
2.6 The Bending Theory ….. 20
2.6.1 Technique One (3 Point Bend Test) … 22
2.6.2 Technique Two (4 Point Bend Test) …. 24
2.7 The efficiency of a conventional photovoltaic cell ….. 24

CHAPTER THREE EXPERIMENTAL PROCEDURE/ MODELING

3.1 Introduction ……29
3.2 Experimental Work ….. 29
3.2.1 Dimensions of the Solar Cell …… 29
3.2.2 Sample Preparation and Cleaning . 30
3.2.3 Solar Cell Manufacturing Procedure … 30
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ASARE, Joseph |Dept. of Theoretical Physics (AUST) viii
3.3.4 Characterization of Bendable OPV Device and Layers ….. 33
3.3.5 TIRA Test …. 33
3.4 Modeling and Simulation ……….. 35
3.4.1 ―Optical‖ Modeling …. 35
3.3.2 Matlab Modeling …….. 36
3.3.3 Abaqus Modeling . 36

CHAPTER FOUR RESULTS AND DISCUSSION

4.1 Introduction ……….. 39
4.2 Results and Discussion ….. 39

CHAPTER FIVE CONCLUSION AND RECOMMENDATION

5.1 Conclusion . 45
5.2 Recommendation …. 45
APPENDIX ……….. 46
REFERENCE ……….. 48

REFERENCE

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