Reducing energy loss via tuning energy levels of polymer acceptors for efficient all-polymer solar cells
Journal article, 2020
The open-circuit voltage (Voc) of all-polymer solar cells (all-PSCs) is typically lower than 0.9 V even for the most efficient ones. Large energy loss is the main reason for limiting Voc and efficiency of all-PSCs. Herein, through materials design using electron deficient building blocks based on bithiophene imides, the lowest unoccupied molecular orbital (LUMO) energy levels of polymer acceptors can be effectively tuned, which resulted in a reduced energy loss induced by charge generation and recombination loss due to the suppressed charge-transfer (CT) state absorption. Despite a negligible driving force, all-PSC based on the polymer donor and acceptor combination with well-aligned energy levels exhibited efficient charge transfer and achieved an external quantum efficiency over 10% while maintaining a large Voc of 1.02 V, leading to a 9.21% efficiency. Through various spectroscopy approaches, this work sheds light on the mechanism of energy loss in all-PSCs, which paves an avenue to achieving efficient all-PSCs with large Voc and drives the further development of all-PSCs.
all-polymer solar cells
energy level modulation
photovoltage
polymer acceptors
energy loss
Author
Huiliang Sun
Hong Kong University of Science and Technology
Southern University of Science and Technology
Bin Liu
Beijing University of Technology
Southern University of Science and Technology
Jianwei Yu
Linköping University
Xianshao Zou
Lund University
Guangye Zhang
eFlexPV Ltd
Yujie Zhang
Southern University of Science and Technology
Wei Zhang
Guangzhou University
Mengyao Su
Southern University of Science and Technology
Qunping Fan
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Kun Yang
Southern University of Science and Technology
Jianhua Chen
Southern University of Science and Technology
He Yan
Hong Kong University of Science and Technology
Feng Gao
Linköping University
Xugang Guo
Southern University of Science and Technology
Science China Chemistry
1674-7291 (ISSN) 18691870 (eISSN)
Vol. 63 12 1785-1792Subject Categories
Other Physics Topics
Energy Systems
Condensed Matter Physics
DOI
10.1007/s11426-020-9826-4