Conformation tuning of simple non-fused electron acceptors via oxygen and sulfur substitutions and its effects on photovoltaics
Conformation tuning of simple non-fused electron acceptors via oxygen and sulfur substitutions and its effects on photovoltaics
复制标题
通过氧和硫取代来调整简单非稠合电子受体的构象及其对光伏的影响
DOI：
10.1088/2399-7532/abf337
复制
发表时间：
2021
影响因子：
--
通讯作者：
Hongzheng Chen
中科院分区：
文献类型：
--
作者：
Zhenghui Yao;Yaokai Li;Shuixing Li;Minmin Shi;Hongzheng Chen
抽象。通过改变氧和硫取代基的数目和位置，采用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。这四种受体为研究杂原子对基于它们与典型聚合物供体PBDB-T的共混物的有机太阳能电池（OSC）性能的影响提供了良好的分子模型。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节。逐渐增加的氧原子可以影响分子内非共价（O S，O H）相互作用，主链平面性，薄膜形态，以及电气和光伏性能显着。当用S取代O原子时，由于O → S的库仑吸引力和O → H的氢键相互作用的减弱，主链的扭转角从3.5°增加到97°。随着氧原子数目的增加，吸收逐渐红移，能级升高。结果，器件的功率转换效率从4.06%（PTS-4F）增加到6.81%（PTO-4F）。本研究通过精细控制分子内弱的非共价相互作用和分子构象，为优化简单非稠合受体和器件性能提供了有益的分子设计指导。
Abstract. 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.