Reducing the Excitonic Loss at Donor/Acceptor Heterojunction with Negligible Exciton Dissociation Driving Force

作者：Xue, Wenyue; Zhang, Zhuoqiong; So, Shu Kong; Song, Yin; Wei, Zhixiang; Ma, Wei; Yan, Han^*

来源：ACS Applied Energy Materials, 2022.

DOI：10.1021/acsaem.2c01601

• doped organic solar cell
• molecular doping
• doping efficiency
• non-fullerene acceptor
• exciton dissociation
• nonradiative recombination

A breakthrough for non-fullerene acceptors (NFAs) is their efficient photocharge generation and low nonradiative voltage loss (AVnrad) in a condition of negligible energy offset (delta G(S1,CT)) between the lowest singlet state (S-1) and the relaxed charge transfer (CT) state. This inspires the idea of viewing the donor/acceptor (D/A) binary blend as a single component in organic solar cells (OSCs) and attracts tremendous studies on the D/A pairs with negligible delta GS(1,CT). Unfortunately, an arbitrarily chosen material combination usually results in severe photovoltaic performance loss. To solve this problem, we present a diffused heterojunction (DHJ) doping strategy at the D/A heterojunction with small delta GS(1,CT). The electronic doping alleviates the performance loss by accelerating the exciton dissociation rate and reducing the delta V-nrad. After examining the DHJ doping strategy in other six NFA material combinations, we are confident to point out that our work opens an avenue for pursuing intrinsic high OSC performance comparing with other single-component photovoltaic technologies.

• 单位
  西安交通大学; 北京理工大学; 国家纳米科学中心; 中国科学院