Hole Transfer Originating from Weakly Bound Exciton Dissociation in Acceptor-Donor-Acceptor Nonfullerene Organic Solar Cells.

Autor: Niu MS; School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China., Wang KW; School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing , Wuhan University of Technology , 430070 Wuhan , Hubei , China., Yang XY; School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China., Bi PQ; School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China., Zhang KN; School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China., Feng XJ; School of Microelectronics , Shandong University , 250100 Jinan , Shandong , China., Chen F; Department of Mechanical, Materials and Manufacturing Engineering , The University of Nottingham Ningbo China , Ningbo 315100 , P.R. China., Qin W; School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China., Xia JL; School of Chemistry, Chemical Engineering and Life Science, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing , Wuhan University of Technology , 430070 Wuhan , Hubei , China., Hao XT; School of Physics, State Key Laboratory of Crystal Materials , Shandong University , 250100 Jinan , Shandong , China.; ARC Centre of Excellence in Exciton Science, School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia.
Jazyk: angličtina
Zdroj: The journal of physical chemistry letters [J Phys Chem Lett] 2019 Nov 21; Vol. 10 (22), pp. 7100-7106. Date of Electronic Publication: 2019 Nov 05.
DOI: 10.1021/acs.jpclett.9b02837
Abstrakt: The underlying hole-transfer mechanism in high-efficiency OSC bulk heterojunctions based on acceptor-donor-acceptor (A-D-A) nonfullerene acceptors (NFAs) remains unclear. Herein, we study the hole-transfer process between copolymer donor J91 and five A-D-A NFAs with different highest occupied molecular orbital energy offsets (Δ E H ) (0.05-0.42 eV) via ultrafast optical spectroscopies. Transient absorption spectra reveal a rapid hole-transfer rate with small Δ E H , suggesting that a large energy offset is not required to overcome the exciton binding energy. Capacitance-frequency spectra and time-resolved photoluminescence spectra confirm the delocalization of an A-D-A-structured acceptor exciton with weak binding energy. Relative to the hole-transfer rate, hole-transfer efficiency is the key factor affecting device performance. We propose that holes primarily stem from weakly bound acceptor exciton dissociation, revealing a new insight into the hole-transfer process in A-D-A NFA-based OSCs.
Databáze: MEDLINE