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Efficient Nonfullerene Organic Solar Cells with Small Driving Forces for Both Hole and Electron Transfer
Author(s) -
Chen Shangshang,
Wang Yuming,
Zhang Lin,
Zhao Jingbo,
Chen Yuzhong,
Zhu Danlei,
Yao Huatong,
Zhang Guangye,
Ma Wei,
Friend Richard H.,
Chow Philip C. Y.,
Gao Feng,
Yan He
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201804215
Subject(s) - homo/lumo , materials science , organic solar cell , quantum efficiency , acceptor , photocurrent , energy conversion efficiency , photochemistry , electroluminescence , optoelectronics , nanotechnology , polymer , chemistry , physics , molecule , organic chemistry , layer (electronics) , composite material , condensed matter physics
State‐of‐the‐art organic solar cells (OSCs) typically suffer from large voltage loss ( V loss ) compared to their inorganic and perovskite counterparts. There are some successful attempts to reduce the V loss by decreasing the energy offsets between the donor and acceptor materials, and the OSC community has demonstrated efficient systems with either small highest occupied molecular orbital (HOMO) offset or negligible lowest unoccupied molecular orbital (LUMO) offset between donors and acceptors. However, efficient OSCs based on a donor/acceptor system with both small HOMO and LUMO offsets have not been demonstrated simultaneously. In this work, an efficient nonfullerene OSC is reported based on a donor polymer named PffBT2T‐TT and a small‐molecular acceptor (O‐IDTBR), which have identical bandgaps and close energy levels. The Fourier‐transform photocurrent spectroscopy external quantum efficiency (FTPS‐EQE) spectrum of the blend overlaps with those of neat PffBT2T‐TT and O‐IDTBR, indicating the small driving forces for both hole and electron transfer. Meanwhile, the OSCs exhibit a high electroluminescence quantum efficiency (EQE EL ) of ≈1 × 10 −4 , which leads to a significantly minimized nonradiative V loss of 0.24 V. Despite the small driving forces and a low V loss , a maximum EQE of 67% and a high power conversion efficiency of 10.4% can still be achieved.