有機共軛高分子太陽電池之製程研究

學生：林豫立 指導教授：洪勝富 教授

國立清華大學光電工程研究所碩士班

摘要

傳統太陽電池以矽為材料，由於矽太陽電池材料成本過高與製程複雜等缺點，有機共軛高分子太陽電池的出現提供了一條解決目前在傳統太陽電池上所遇困難的方法。有機共軛高分子太陽電池由於具備在可饒性機板上成膜與大尺寸製程等特性，在太陽電池的使用上提供了更多樣性的選擇。
在本研究裡面以P3HT(poly(3-hexylthiophene)與PCBM ( [6,6]-phenyl-C61-butyric acid methylester )當作電洞電子的傳輸材料，在結構上則是以P3HT與PCBM混合(blend)於鄰二氯苯(DCB)（1,2 Dichlorobenzene）中，並利用旋轉塗佈(spin-coating)的方式在ITO基板上來成膜。此塊材異質接面(bulk heterojunction)能夠有效的提高載子的傳輸效率。
本論文主要在研究元件製程的改變對太陽電池特性的影響，並藉由不同的實驗條件來提高元件之能量轉換效益。而能量轉換效益可高達5.3%。另外在本論文中也利用了緩衝層的技術來提高元件的厚度，增加入射光的吸收。藉由厚度的增加，能量轉換效益提高了12%。

關鍵字:太陽能電池、有機、高分子、P3HT(poly(3-hexylthiophene)、PCBM( [6,6]-phenyl-C61-butyric acid methylester )

Investigation of fabrication in Conjugated polymer solar cells

Student：Yu-Li Lin Advisors：Prof. Sheng-Fu Horng

Institute of Photonics
National Tsing Hua University

Abstract

The traditional solar cell is as the material with the silicon, because silicon solar cell material cost too high and fabrication is too complicated, the appearance of organic conjugated polymer solar cell has offered one to solve difficult methods met on the traditional solar cell at present. Because organic conjugated polymer solar cell possess flexibility and the potential to scale up to large area., have offered more diversified choice in the use of the solar cell.
In our study,we use P3HT(poly (3 - hexylthiophene) and PCBM ([6,6 ] - phenyl-C61-butyric acid methylester) as donor and acceptor , we blended P3HT and PCBM in 1, 2 Dichlorobenzene, and use spin-coating to fabricate on ITO glass base. This bulk heterojunction structure can help carriers transport .
In this study we try to realize the effect that change fabriations and enhance power convsion efficiency, reaches 5.3%. We use buffer layer to increase the thickness and enhance the absorption of light . By the increase of the thickness, power conversion efficiency has improve 12%.
Keyword: solar cell , photovoltaic ,polymer ,PCBM ,P3HT

參考文獻
1. D. M. Chapin, C. S. Fuller, and G.L. Pearson, “A New Silicon pn Junction Photocell for Converting Solar Radiation into Electrical Power,” J. Appl. Phys. 25, 676 (1954).

2. J. Zhao, A. Wang, and M. A. Green, “24.5% efficiency silicon PERT cells on MCZ substrates and 24.7% efficiency PERL cells on FZ substrates,” Prog. Photovolt. : Res. Appl. 7, 471 (1999).

3. K. M. Coakley and M. D. McGehee, “Conjugated polymer photovoltaic cells,” Chem. Mater. 16, 4533 (2004).

4. C. W. Tang, “Two-layer organic photovoltaic cell,” Appl. Phys. Lett. 48, 183 (1986).

5. G. Yu, K. Pakbaz, and A. J. Heeger, “Semiconducting polymer diodes: Large size, low cost photodetectors with excellent visible-ultraviolet sensitivity,” Appl. Phys. Lett. 64, 3422 (1994).

6. Kyungkon Kim, “Roles of donor and acceptor nanodomains in 6% efficient thermally annealed polymer photovoltaics” Appl. Phys. Lett. 90, 163511 (2007)

7. J. Nelson, “Organic photovoltaic films,” Curr. Opin. Solid State Mater. Sci. 6, 87 (2002).

8. B. O’Regan and M. A. Gr□tzel, “A low cost, high efficiency solar cell based on dye-sensitized colloidal TiO2 films,” Nature 353, 737 (1991)

9. website of “Research Institute of Innovative Technology for the Earth, RITE” (http://www.rite.or.jp/)

10. Yang Yang“High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends” Nature materials VOL 4 NOVEMBER 2005

11. W. U. Huynh, J. J. Dittmer, N. Teclemariam, D. Milliron, and A. P. Alivisatos, K. W. J. Barnham, “Charge Transport in Hybrid Nanorod-Polymer Composite Photovoltaic. Cells,” Phys. Rev. B 67, 115326 (2003).

12. I. G. Hill, A. Rajagopal, A. Kahn, and Y. Hu, “Molecular level alignment at organic semiconductor-metal interfaces,” Appl. Phys. Lett. 73, 662 (1998).

13. H. Ishii, K. Sugiyama, E. Ito, and K. Seki, “Energy Level Alignment and Interfacial Electronic Structures at Organic/Metal and Organic/Organic Interfaces,” Adv. Mater. 11, 605 (1999).

14. I. G. Hill, A. J. Makinen, and Z. H. Kafafi, “Initial stages of metal/organic semiconductor interface formation,” J. Appl. Phys. 88, 889 (2000).

15. S. Karg, M. Meier, and W. Riess, “Light-emitting diodes based on poly-p-phenylene-vinylene: I. Charge-carrier injection and transport,” J. Appl. Phys. 82, 1951 (1997).

16. R. H. Fowler and L. Nordheim, Proc. R. Soc. London Ser. A 119, 173 (1928).

17. N. F. Mott and D. Gurney. Electronic Processes in Ionic Crystals. Oxford, New York, 1940

18. J. Frenkel, “On pre-breakdown phenomena in insulators and electric semiconductors,” Phys. Rev. 54, 647 (1938).

19. D. M. Pai, “Transient photoconductivity in poly(N-vinylcarbazole),” J. Chem. Phys. 52, 2285 (1970).

20. P. W. M. Blom, M. J. M. de Jong, and M. G. van Munster, “Electric-field and temperature dependence of the hole mobility in poly(p-phenylene vinylene),” Phys. Rev. B 55, 656 (1997).

21. Hsin-Fei Meng “General method to solution-process multilayer polymer light-emitting diodes” Appl. Phys. Lett.88, 163501 (2006)