By altering the number and position of oxygen and sulfur substitutions, four simple non-fused electron acceptors, PTO-4F, PDO-4F, PDS-4F and PTS-4F, were synthesized via feasible two-step reactions. These four acceptors serve as good molecular models to investigate the heteroatom effects on performance of organic solar cells (OSCs) based on their blends with typical polymer donor PBDB-T. The quantity of intramolecular noncovalent bonds, conformation of the molecules and performance of OSCs can be easily adjusted. Gradually increasing oxygen atoms could influence the intramolecular noncovalent (O⋯S, O⋯H) interactions, backbone planarity, film morphology, and electrical and photovoltaic properties significantly. When replacing O atoms with S atoms, the torsional angle of the backbone increases from 3.5 to 97 owing to the reduction of O⋯S attractive coulomb interaction and/or O⋯H hydrogen bonding interaction. With increasing oxygen atom numbers, the absorption is red-shifted gradually and the energy levels are lifted. As a result, the power conversion efficiency of the device increases from 4.06% (PTS-4F) to 6.81% (PTO-4F). This study provides helpful molecular design guideline for the optimization of simple non-fused acceptors and device performances by finely controlling the weak intramolecular noncovalent interactions and molecular conformations.

通过改变氧和硫取代的数量和位置，通过可行的两步反应合成了四种简单的非稠合电子受体 PTO-4F、PDO-4F、PDS-4F 和 PTS-4F。这四种受体作为良好的分子模型，基于它们与典型聚合物供体 PBDB-T 的共混物研究杂原子对有机太阳能电池 (OSC) 性能的影响。分子内非共价键的数量、分子的构象和 OSC 的性能可以很容易地调整。逐渐增加的氧原子会显着影响分子内非共价（O⋯S、O⋯H）相互作用、骨架平面度、薄膜形态以及电学和光伏特性。当用 S 原子代替 O 原子时，主链的扭转角从 3 增加。由于 O⋯S 吸引力库仑相互作用和/或 O⋯H 氢键相互作用的减少，从 5 到 97。随着氧原子数的增加，吸收逐渐红移，能级升高。因此，器件的功率转换效率从 4.06% (PTS-4F) 提高到 6.81% (PTO-4F)。该研究通过精细控制弱分子内非共价相互作用和分子构象，为优化简单的非融合受体和器件性能提供了有用的分子设计指南。