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Fullerene Adducts Bearing Cyano Moiety for Both High Dielectric Constant and Good Active Layer Morphology of Organic Photovoltaics
Author(s) -
Zhang Sheng,
Zhang Zijian,
Liu Jun,
Wang Lixiang
Publication year - 2016
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201600350
Subject(s) - organic solar cell , materials science , acceptor , homo/lumo , polymer solar cell , active layer , moiety , electron acceptor , fullerene , energy conversion efficiency , photoactive layer , dielectric , organic electronics , photochemistry , nanotechnology , polymer , organic chemistry , optoelectronics , layer (electronics) , molecule , chemistry , composite material , physics , thin film transistor , transistor , voltage , quantum mechanics , condensed matter physics
Power conversion efficiency (PCE) of organic photovoltaics (OPVs) lags behind of inorganic photovoltaics due to low dielectric constants ( ε r ) of organic semiconductors. Although OPVs with high ε r are attractive in theory, practical demonstration of efficient OPV devices with high‐ ε r materials is in its infancy. This is largely due to the contradiction between the requirements of high ε r and good donor:acceptor blend morphology in the bulk heterojunction. Herein, a series of fullerene acceptors is reported bearing a polar cyano moiety for both high ε r and good donor:acceptor blend morphology. These cyano‐functionalized acceptors ( ε r = 4.9) have higher ε r than that of the widely used acceptor, [6,6]‐phenyl‐C 61 ‐butyric acid methyl ester (PC 61 BM) ( ε r = 3.9). The high ε r is realized without decrease of electron mobility and change of the lowest unoccupied molecular orbital/highest occupied molecular orbital (LUMO/HOMO) energy levels. Although the cyano‐functionalized acceptors have increased polarity, they still exhibit good compatibility with the typical donor polymer. Polymer solar cells based on the cyano‐functionalized acceptors exhibit good active layer morphology and show better device performance (PCE = 5.55%) than that of PC 61 BM (PCE = 4.56%).