Achieving over 16％ efficiency for single-junction organic solar cells

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2019,（6）
• 页码范围: 746-752
• 页数: 7页
• 语种: 英文

摘要

To achieve high photovoltaic performance of bulk hetero-junction organic solar cells (OSCs),a range of critical factors including absorption profiles,energy level alignment,charge carrier mobility and miscibility of donor and acceptor materials should be carefully considered.For electron-donating materials,the deep highest occupied molecular orbital (HOMO) energy level that is beneficial for high open-circuit voltage is much appreciated.However,a new issue in charge transfer emerges when matching such a donor with an acceptor that has a shallower HOMO energy level.More to this point,the chemical strategies used to enhance the absorption coefficient of acceptors may lead to increased molecular crystallinity,and thus result in less controllable phase-separation ofphotoactive layer.Therefore,to realize balanced photovoltaic parameters,the donor-acceptor combinations should simultaneously address the absorption spectra,energy levels,and film morphologies.Here,we selected two non-fullerene acceptors,namely BTPT-4F and BTPTT-4F,to match with a wide-bandgap polymer donor P2F-EHp consisting of an imidefunctionalized benzotriazole moiety,as these materials presented complementary absorption and well-matched energy levels.By delicately optimizing the blend film morphology,we demonstrated an unprecedented power conversion efficiency of over 16％ for the device based on P2F-EHp:BTPTT-4F,suggesting the great promise of materials matching toward high-performance OSCs.