Efficient Top Illuminated Polymer Solar Cells with Distributed Bragg Reflector on Flexible Metal Substrate
- 발행기관 Pohang University of Science and Technology - Division of Advanced Materials Science
- 발행년도 2012
- 학위수여년월 2012. 8
- 학위명 석사
- 학과 및 전공 일반대학원 첨단재료과학부
- 실제URI http://www.dcollection.net/handler/postech/000001391481
- 본문언어 영어
초록/요약
Thin-film solar cells such as polymer solar cells on flexible substrates are considered the most promising candidates for low-cost photovoltaic devices. Polymer solar cells have many advantages including flexible and unbreakable characteristics, cheap substrate and ease for roll-to-roll fabrication which have potential for broad applications such as energy sources for cellular phone, ID cards and clothes equipped with electronic devices. Previously, people focused on plastic film, PET/ITO film for instance, but its high water vapor permeation rate appears at a distinct disadvantage. Metal substrates like stainless steel (SS) or copper plate can solve this problem. Furthermore, those materials also attract industrial researchers because of their popular applications. However, the high rough and low transparent surface of those metal sheets is obstacle which can impact the performance of thin-film solar cells. In this work, we use a high re-flecting and insulating protective layers comprising of Distributed Bragg Reflector (DBR) to treat the surface. DBR shows high potential to reduce roughness, prevent STS sheet from oxidation during high temperature sintering process and increase the reflectance property. DBR consisting of Ta2O5 and SiO2 was carried out as the back reflector for upper polymer solar cells. Its optical and electrical properties were also examined.
more목차
I. Introduction 1
II. Background 4
2.1 Device Physics of Bulk-heterojunction Organic Photovoltaics (OPVs) 4
2.1.1 Exciton Generation and Charge Carrier Pair Separation 5
2.1.2 Charge Transport and Extraction 7
2.2 Properties of DBR 9
2.3 Stainless Steel Substrate 12
2.4 Research Trends of OPVs on flexible substrate 13
2.5 Industry Trends in OPVs 14
III Experimental 18
3.1 Substrate Preparation 18
3.2 Simulation 19
3.3 Optical Measurement 21
3.4 Electrical Conductivity Measurement 24
3.5 Breakdown Voltage and Bending Measurement 25
3.6 Surface Roughness Test 29
3.7 OPV Device Measurement 32
Ⅳ. Results and Discussions 36
4.1. Simulation Results 36
4.2. Experimental Optical Properties of DBR 43
4.2.1. DBR on Glass and STS 43
4.2.2. DBR and ITO on STS 48
4.2.2. Tilt sunlight 49
4.3. Breakdown Voltage 53
4.4. Roughness 54
4.5. OPV Device Characteristics 56
Ⅴ. Conclusion 63
References 64