Effects of Bending and Stretching on Hybrid Organic- Inorganic Trihalide Perovskite Solar Cells.
ABSTRACT
In the recent decade, hybrid organic- inorganic trihalide perovskite solar cells have attracted significant interest from the scientific community due to their unique optoelectrical properties, ease and low cost of fabrication.
Extensive research has been carried out to understand the electrical and optical properties of this novel material with a view to boosting the efficiency of the system.
However, not much has been done to understand the mechanical properties of the system. The potential brittleness which predisposes the system to crack has not been addressed. In addition, issues with regards to the response of the cell to stretching and bending have not been investigated.
In this research work, lead-based and tin-based perovskite solar cells were modeled and subjected to bending and stretching forces using ABAQUSTM finite element analysis software. Preliminary analysis showed that PET is a more suitable substrate for bending applications while PDMS is more compliant for stretching purposes.
Contour plots obtained showed that the relatively high modulus of elasticity and layer thickness of TiO2 nanocrystals reduces the mechanical performance of the solar cells where flexibility is desirable.
High stress levels were observed on the aluminium contact layer of the structures; this is due to the huge difference in elasticity between aluminium and the organic and organic-inorganic materials.
Although some immediate conclusion can be made from the results presented, implications of some of the results obtained are still unclear. It is therefore recommended that experimental work be undertaken to verify the result obtained from the simulations done.
Further investigation and experimentation into cracks and failure mechanisms not covered in this research is strongly recommended in future work.
TABLE OF CONTENTS
Abstract …………. i
Acknowledgements …….. ii
Table of Contents …. iii
List of Figures ……… v
List of Tables ……. vi
Appendix A ……….. vii
1. CHAPTER ONE: INTRODUCTION
1.0 Background ………………………………… 1
1.1 Unresolved Issues ……………………….. 2
1.2 Aim and Objectives of the Thesis …………………………… 3
1.3 Scope of the Thesis ………………. 3
1.4 Thesis Layout ………………………… 3
2 Chapter Two: Literature Review
2.1 Global and African Energy Challenge ……….. 5
2.2 Photovolatics ………….. 5
2.2.1 Inorganic Solar Cells ………….. 6
2.2.2 Organic Based Solar Cells ……….. 6
2.2.3 Dye Sensitized Solar Cell ………… 7
2.2.4 Carbon Based Solar Cells …….. 8
2.2.5 Perovskite Solar Cells……………….. 9
2.3 Stretchable and Bendable Solar Cells ……….. 10
2.3.1 Flexible and Stretchable Conventional Photovoltaic Technologies …………………….. 10
2.3.2 Flexible and Stretchable Perovskite-Based Solar Cells …………….. 11
3 Chapter Three: Research Methodology
3.1 Overview ……………………. 13
3.2 Analytical Modeling …………….. 13
3.2.1 Bending: Three Point Bend Test Model ………………… 13
3.2.2 Stretching ………………….. 16
3.2.3 Crack Modeling ……………. 17
3.3 Material Properties ………….. 18
3.4 Finite Element Simulation …………….. 19
3.4.1 Geometry Design……………….. 19
3.4.2 Boundary Conditions and Meshing ….. 21
3.4.3 Result Visualisation …………. 23
4 Chapter Four: Results and Discussion
4.1 Introduction …………… 24
4.2 Effects of Stretching ……… 24
4.2.1 Stress Analysis ……. 24
4.2.2 Failure Mechanism …… 28
4.3 Effect of Bending ………… 28
4.3.1 Stress Analysis ………… 28
4.3.2 Failure Mechanism ……….. 30
5 Chapter Five: Conclusion and Recommendations
5.1 Conclusion …………………….. 31
5.2 Recommendations ………….. 31
6 References …………. 32
7 Appendix ……………. 37
INTRODUCTION
1.1 Background
Rapid improvement in man’s living standard and daily living conveniences such as the use of electric bulb, telephone, air conditioners, street lighting systems, transportation, and powering of machineries in industries, are largely due to the availability of energy sources which act as the drivers of these systems.
However, in a bid to generate the required energy needed to operate these systems, various energy sources such as fossil fuels, bio fuels, wind, hydro, nuclear and solar have been exploited each of which has its peculiar advantages and drawbacks.
Some of these includes: water and atmospheric pollution, high cost of maintenance, competition for food, potential dangers of leakage and waste disposal (in nuclear plants) (Win, 2006).
Solar energy seems more promising among all the aforementioned existing sources of energy. Energy from the sun is enormous, clean, cheap and eco-friendly (i.e. carbon free).
It is sustainable and indefinitely renewable since the sun which is its source and central to the sustenance of life is in theory inexhaustible in several millions of years (IEA, 2011; Tsao, et al., 2006).
In addition, solar panel, a photovoltaic device used for photo-conversion can produce electricity at dimension of few millimeters with little or no maintenance needed once installed. They produce electricity silently and are an excellent choice when avoiding noise pollution.
In an effort to harness the abundant energy of the sun for electricity, several photovoltaic systems have been fabricated by researchers.
These systems are varied in power conversion efficiency, which depend on the fabrication technique and materials used. Common photovoltaic systems are the silicon based solar cells, organic solar cells, dye sensitized solar cells, and carbon based solar cells (which are championed by graphene).
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