材料科学
光伏系统
戒指(化学)
类型(生物学)
光电子学
工程物理
有机化学
电气工程
生态学
生物
工程类
化学
作者
Miao Li,Yahui Liu,Yuanyuan Zhou,Lisi Yang,Shuaishuai Shen,Jinsheng Song,Zhishan Bo
标识
DOI:10.1021/acsami.9b19676
摘要
We precisely design and synthesize two A-π-D-π-A type dipyran-cored nonfullerene acceptors (NFAs) Ph-DTDPo-OT and Ph-DTDPi-OT with oxygen atoms at the outer and inner positions, respectively. 3-Hexyloxythiophene is used as the π-spacer to expand the effective conjugation length of the acceptors. These two NFAs possess similar optical band gaps and energy levels. However, the position of the oxygen atom at the dipyran core can markedly influence the molecular packing and aggregation behavior of the resulted acceptors. Ph-DTDPo-OT with a strong intermolecular affinity tends to form larger aggregates blending with PBDB-T, leading to a lower photovoltaic performance; Ph-DTDPi-OT presents good miscibility with PBDB-T and the blend films preferentially adopt a face-on orientation. Ph-DTDPi-OT-based devices display high and balanced hole and electron mobilities, leading to an optimal power conversion efficiency of 11.38%, which is much higher than those of Ph-DTDPo-OT-based ones (7.60%). Moreover, Ph-DTDPi-OT-based devices also exhibit a lower nonradiative recombination voltage loss of 0.268 eV. Our work demonstrates that the π-spacer and chemical structure of the core unit can greatly influence the molecular packing and the morphology of blend films, which are critical to the photovoltaic performance of devices.
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