標題: Reducing Regioisomers of Fullerene-Bisadducts by Tether-Directed Remote Functionalization: Investigation of Electronically and Sterically Isomeric Effects on Bulk-Heterojunction Solar Cells
作者: Liao, Ming-Hung
Lai, Yin-Yu
Lai, Yu-Ying
Chen, Yen-Ting
Tsai, Che-En
Liang, Wei-Wei
Cheng, Yen-Ju
應用化學系
Department of Applied Chemistry
關鍵字: regioisomers;bis-adducts;tether;bulk-heterojunction;solar cells;shallow-trap effect
公開日期: 22-一月-2014
摘要: C-60 bis-adduct containing a mixture of regio-isomers with different LUMO energy levels and steric geometries could greatly affect the morphological and bulk properties. To investigate the regio-isomer effect on solar cell performance, we have successfully designed and synthesized a regio-selective 4-acetatephenyl-4'-methylphenylmethano C-60 bis-adduct (S-APM-CBA) by "tether-directed remote functionalization" strategy and a random 4-acetatephenyl-4'-methylphenylmethano C-60 bis-adduct denoted as R-APM-CBA by traditional cyclopropanation. The dramatic reduction in the number of regio-isomers in S-APM-CBA is confirmed by the H-1 NMR and HPLC measurements and theoretical calculation. Compared to the R-APM-CBA-based device with a J(sc) of 6.63 mA/cm(2), an FF of 44.3% and a PCE of 2.46%, the device using S-APM-CBA yielded a much lower J(sc) of 1.48 mA/cm(2), an FF of 32.2%, and a PCE of 0.38%. Consistently, the electron-only device using S-AMP-CBA exhibited lower electron mobility than the R-AMP-CBA-based device. These results imply that the electronic shallow-trap effect ascribed to the LUMO energy variations turned out to be insignificant in the AMP-CBA system. The lower efficiency and mobility of S-AMP-CBA might due to the assumption that the most probable trans-4-III isomer in S-AMP-CBA prevents the intermolecular facial contact of fullerenes, thereby hindering the electron transporting. Furthermore, the nanomorphology of S-AMP-CBA and R-AMP-CBA active layers could be different because of their different three-dimensional structures. This research demonstrated that steric effect of regio-isomers in a given C-60 bis-adduct is more crucial than electronic shallow-trap effect.
URI: http://dx.doi.org/10.1021/am404485t
http://hdl.handle.net/11536/23588
ISSN: 1944-8244
DOI: 10.1021/am404485t
期刊: ACS APPLIED MATERIALS & INTERFACES
Volume: 6
Issue: 2
起始頁: 996
結束頁: 1004
顯示於類別:期刊論文


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  1. 000330201900036.pdf