Premium
Achieving Fast Charge Separation and Low Nonradiative Recombination Loss by Rational Fluorination for High‐Efficiency Polymer Solar Cells
Author(s) -
Sun Chenkai,
Pan Fei,
Chen Shanshan,
Wang Rui,
Sun Rui,
Shang Ziya,
Qiu Beibei,
Min Jie,
Lv Menglan,
Meng Lei,
Zhang Chunfeng,
Xiao Min,
Yang Changduk,
Li Yongfang
Publication year - 2019
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.201905480
Subject(s) - quinoxaline , materials science , thiophene , acceptor , homo/lumo , energy conversion efficiency , polymer , polymer solar cell , photochemistry , open circuit voltage , optoelectronics , molecule , voltage , organic chemistry , chemistry , electrical engineering , physics , engineering , composite material , condensed matter physics
Abstract Four low‐cost copolymer donors of poly(thiophene‐quinoxaline) (PTQ) derivatives are demonstrated with different fluorine substitution forms to investigate the effect of fluorination forms on charge separation and voltage loss ( V loss ) of the polymer solar cells (PSCs) with the PTQ derivatives as donor and a A–DA'D–A‐structured molecule Y6 as acceptor. The four PTQ derivatives are PTQ7 without fluorination, PTQ8 with bifluorine substituents on its thiophene D‐unit, PTQ9, and PTQ10 with monofluorine and bifluorine substituents on their quinoxaline A‐unit respectively. The PTQ8‐ based PSC demonstrates a low power conversion efficiency (PCE) of 0.90% due to the mismatch in the highest occupied molecular orbital (HOMO) energy levels alignment between the donor and acceptor. In contrast, the devices based on PTQ9 and PTQ10 show enhanced charge‐separation behavior and gradually reduced V loss , due to the gradually reduced nonradiative recombination loss in comparison with the PTQ7‐based device. As a result, the PTQ10‐based PSC demonstrates an impressive PCE of 16.21% with high open‐circuit voltage and large short‐circuit current density simultaneously, and its V loss is reduced to 0.549 V. The results indicate that rational fluorination of the polymer donors is a feasible method to achieve fast charge separation and low V loss simultaneously in the PSCs.