Architectural Engineering of Rod鈥揅oil Compatibilizers for Producing Mechanically and Thermally Stable Polymer Solar Cells

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• 作者：Hyeong Jun Kim ; Jae-Han Kim ; Ji-Ho Ryu ; Youngkwon Kim ; Hyunbum Kang ; Won Bo Lee ; Taek-Soo Kim ; Bumjoon J. Kim
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：8
• 期：10
• 页码：10461-10470
• 全文大小：675K
• ISSN：1936-086X

文摘

While most high-efficiency polymer solar cells (PSCs) are made of bulk heterojunction (BHJ) blends of conjugated polymers and fullerene derivatives, they have a significant morphological instability issue against mechanical and thermal stress. Herein, we developed an architecturally engineered compatibilizer, poly(3-hexylthiophene)-graft-poly(2-vinylpyridine) (P3HT-g-P2VP), that effectively modifies the sharp interface of a BHJ layer composed of a P3HT donor and various fullerene acceptors, resulting in a dramatic enhancement of mechanical and thermal stabilities. We directly measured the mechanical properties of active layer thin films without a supporting substrate by floating a thin film on water, and the enhancement of mechanical stability without loss of the electronic functions of PSCs was successfully demonstrated. Supramolecular interactions between the P2VP of the P3HT-g-P2VP polymers and the fullerenes generated their universal use as compatibilizers regardless of the type of fullerene acceptors, including mono- and bis-adduct fullerenes, while maintaining their high device efficiency. Most importantly, the P3HT-g-P2VP copolymer had better compatibilizing efficiency than linear type P3HT-b-P2VP with much enhanced mechanical and thermal stabilities. The graft architecture promotes preferential segregation at the interface, resulting in broader interfacial width and lower interfacial tension as supported by molecular dynamics simulations.

Keywords:

thermal and mechanical stability of polymer solar cell; rod鈭抍oil copolymer; graft and block architecture; universal compatibilizer; coarse-grained molecular dynamics simulations