邁向穩定高分子太陽能電池：側鏈末端溴修飾之可交聯喹喔啉高分子合成，其強化元件主動層架構之研究

En Route to Stable Polymer Solar Cells: Strengthening Morphology of the Active Layer with Br-substituted Crosslinkable Quinoxalines

簡韻宸(Yun-Chen Chien)

指導教授 ： 周必泰

國立臺灣大學/理學院/化學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.10544

摘要

有機太陽能電池之主動層材料由高分子（電子予體）與富勒希衍生物（電子受體）所構成，因為可以降低成本，以及大面積製程，故成為再生能源之新星。在過去的研究中已經藉由材料研發以及製程的調控達到10.8%的高效率，但是卻不能保證其轉換效能的穩定，是此技術欲商業化必須面臨之主要挑戰。為了提升其效能之穩定度，控制主動層之型態（morphology）為重要研究課題。
本研究提出合成末端帶溴作為光致交聯劑之氟化喹喔啉（quinoxaline）單體之途徑，並以Stille coupling 共聚反應合成不同含溴比例之之高分子搭配PC71BM作為主動層材料並製成反式結構之高分子太陽能電池，並經由照射紫外光產生交聯反應以穩定主動層之型態，並探討不同交聯比例之高分子與主動層型態穩定度之關係。
所有合成之支鏈末端帶有溴作為交聯劑之高分子未曝光前皆可溶於溶劑，而曝光後則對溶劑有抗性；而末端帶有溴亦對其光電性質（如高分子之重複單元數、HOMO、LUMO及能階差等）無顯著影響。實驗結果顯示具交聯劑者經由紫外光照射引發交聯反應，能有效的降低主動層中高分子與PCBM相互聚集的效應，以穩定其效率表現。故於高分子側鏈修飾交聯劑可以提升主動層之穩定度。

關鍵字

喹喔啉 ； 交聯 ； 穩定化

並列摘要

The active layer of polymer solar cell is composed of a semiconducting polymer (electron donor) and fullerene derivative (electron acceptor). It is widely known that performance of polymer solar cell is largely affected by the nano-scaled morphology of donor polymer and fullerene acceptor. With optimized process, power conversion efficiency had been enhanced to the highest 10.8% reported in 2014. However, it’s still a challenge to be commercialized due to the instability. In order to maintain the peak performance of device for practical application, it’s important to further research and improve morphology stability.
In this work, on the purpose of stabilizing morphology of active layer, a synthetic route of fluorinated quinoxaline-based D-A copolymer with primary Br attached on the end of alkyl side chain as crosslink unit had been reported and series of polymer with different percentage of crosslink unit were synthesized via Stille cross coupling. Introducing terminal Br as crosslink to quinoxaline-based polymers unit does not significantly influence photochemical and photophysical properties of polymers. Photocrosslinking reaction was confirmed by solvent resistance tests after exposed to UV. BHJ devices were fabricated in inverted configuration with Br-substituted polymers (PBDT-pTFQ-Br0, PBDT-pTFQ-Br25 and PBDT-pTFQ-Br50) as electron donor and PC71BM as electron acceptor. Photocrosslinking dramatically enhanced the stability of active layer via preventing phase segregation attributed to PC71BM clustering. The stability of device was improved and power conversion efficiency retained after stored under atmosphere without any encapsulation via UV-induced crosslinking reaction.

並列關鍵字

quinoxaline ； crosslinking ； stability

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