A Non-fullerene Acceptor with Enhanced Intermolecular π‑Core Interaction for High-Performance Organic Solar Cells

Understanding
the molecular structure and self-assembly of thia­diazole-derived
non-fullerene acceptors (NFAs) is very critical for elucidating the
origin of their extraordinary charge generation and transport properties
that enable high power conversion efficiencies to be achieved in these
systems. A comprehensive crystallographic study on a state-of-the-art
NFA, Y6, and its selenium analog, CH1007, has been conducted
which revealed that the face-to-face π-core
interaction induced by benzo­[2,1,3]­thia­diazole S–N-containing
moieties plays a significant role in governing the molecular geometries
and unique packing of Y6 and CH1007 to ensure their superior
charge-transport properties. Moreover, benefitting from the red-shifted
optical absorption via selenium substitution, photo­voltaic devices
based on a PM6:CH1007:PC71BM ternary blend
delivered an exceptionally high short-circuit current of 27.48 mA/cm2 and a power conversion efficiency of 17.08%.

阐明噻二唑衍生非富勒烯受体（thiadiazole-derived non-fullerene acceptors, NFAs）的分子结构与自组装行为，对于揭示其卓越的电荷产生与传输性能的本源至关重要，而该性能正是此类体系实现高功率转换效率的核心基础。本研究针对当前主流非富勒烯受体Y6及其硒类似物CH1007开展了全面的晶体学研究，结果表明：由含苯并[2,1,3]噻二唑S-N基团诱导产生的面对面π核相互作用，在调控Y6与CH1007的分子几何构型与独特堆积方式、进而赋予其优异电荷传输性能的过程中发挥了关键作用。此外，得益于硒取代带来的光学吸收红移效应，基于PM6:CH1007:PC71BM三元共混体系的光伏器件实现了高达27.48 mA/cm²的短路电流与17.08%的功率转换效率。