State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
University of Science and Technology of China, Hefei, 230026, P. R. China.
Macromol Rapid Commun. 2018 Jan;39(2). doi: 10.1002/marc.201700505. Epub 2017 Oct 24.
For polymer solar cells (PSCs), efficient polymer electron acceptors are always based on strong electron-withdrawing imide unit or boron-nitrogen coordinative bond (B←N). In this paper, a new polymer electron acceptor based on thiophene-S,S-dioxide (TDO) unit is reported. The polymer electron acceptor, PBDT-TDO, consists of alternating TDO unit and 4,8-bis(alkylthienyl)-2-yl]benzo[1,2-b:4,5-b']dithiophene (BDT) unit. For comparison, a control polymer with alternating BDT unit and thiophene unit has also been synthesized. Replacing thiophene unit with TDO unit in the polymer backbone leads to large downshift of lowest unoccupied molecular orbital/highest occupied molecular orbital energy levels by 0.9 eV/0.4 eV, which is attributed to the dearomatization and electron deficiency of TDO unit. The replacement also leads to redshift of absorption spectra by ≈110 nm. PSC device with PBDT-TDO as the electron acceptor shows photovoltaic response with the preliminary power conversion efficiency of 0.64%. This work suggests a new approach to design polymer electron acceptors using the TDO unit.
对于聚合物太阳能电池（PSCs），高效的聚合物电子受体通常基于强吸电子酰亚胺单元或硼-氮配位键（B←N）。本文报道了一种基于噻吩-S，S-二氧化物（TDO）单元的新型聚合物电子受体。聚合物电子受体 PBDT-TDO 由交替的 TDO 单元和 4,8-双（烷基噻吩基）-2-基]苯并[1,2-b：4,5-b']二噻吩（BDT）单元组成。为了进行比较，还合成了具有交替的 BDT 单元和噻吩单元的对照聚合物。在聚合物主链中用 TDO 单元取代噻吩单元会导致最低未占据分子轨道/最高占据分子轨道能级向下移动 0.9eV/0.4eV，这归因于 TDO 单元的去芳构化和缺电子性。这种取代还会导致吸收光谱红移约 110nm。以 PBDT-TDO 为电子受体的 PSC 器件表现出光伏响应，初步功率转换效率为 0.64%。这项工作为使用 TDO 单元设计聚合物电子受体提供了一种新方法。
