Alkyloxime-Substituted Thiophene-Based Wide-Band-Gap Polymer Donor Achieving a High Short Circuit Current Density of 30 mA cm<sup>–2</sup> in Organic Solar Cells
作者:Yunsheng Jiang、Haitao Liu、Xu Li、Yi Yuan、Jinliang Wang、Bo Cui、Yuning Li
DOI:10.1021/acs.chemmater.2c00929
日期:2022.5.10
A new polymer TTOTCl with a repeat unit consisting of a chlorinated thienyl-substituted benzo[1,2-b:4,5-b′]dithiophene (BDTCl) donor unit, a thiophene spacer, and an alkyloxime-substituted thiophene (TO) acceptor unit is reported as a wide-band-gap donor for nonfullerene acceptor-based organic solar cells (OSCs). The optical band gap (Egopt = 1.97 eV), the highest occupied molecular orbital (HOMO) energy level (EHOMO = −5.48 eV), and the lowest unoccupied molecular orbital (LUMO) energy level (ELUMO = −3.51 eV) of TTOTCl match well with the nonfullerene acceptor Y6 (Egopt = 1.33 eV; EHOMO = −5.65 eV; ELUMO = −4.10 eV). TTOTCl also showed a high space charge-limited current (SCLC) hole mobility of 1.36 × 10–3 cm2 V–1 s–1. OSCs using TTOTCl as the donor and Y6 as the acceptor achieved a high power conversion efficiency (PCE) of up to 14.42% with a record high Jsc of 30.00 mA cm–2 along with a Voc of 0.70 V and a fill factor (FF) of 0.68. The PCE was further improved to 15.43% using a hole transport enhancement layer, with an enhanced Voc and FF of 0.72 V and 0.71, respectively. The unencapsulated OSC device showed excellent long-term stability in ambient air with a 90.4% retention in the PCE over 30 days.
一种新型聚合物TTOTCl,其重复单元由氯化噻吩基取代的苯并[1,2-b:4,5-b′]二噻吩(BDTCl)供体单元、噻吩间隔层和烷基肟取代的噻吩(TO)受体单元组成,被报道为非富勒烯受体有机太阳能电池(OSC)的宽带隙供体。TTOTCl的光带隙(Egopt = 1.97 eV)、最高被占分子轨道(HOMO)能级(EHOMO = -5.48 eV)和最低未占分子轨道(LUMO)能级(ELUMO = -3.51 eV)与非富勒烯受体Y6(Egopt = 1.33 eV;EHOMO = -5.65 eV;ELUMO = -4.10 eV)非常匹配。TTOTCl还表现出1.36×10-3 cm2 V-1 s-1的高空间电荷限制电流(SCLC)空穴迁移率。使用TTOTCl作为供体和Y6作为受体的OSC实现了高达14.42%的高功率转换效率(PCE),并创下了30.00 mA cm-2的Jsc记录,Voc为0.70 V,填充