Benzotriazole-Featured Polymer Acceptors Toward As-Cast All-Polymer Solar Cells with a Remarkable Short-Circuit Current Density

作者：Luo, Mei; Chen, Yinchu; Zhang, Lianjie^*; Yuan, Dong; Zhang, Zesheng; Kong, Lingchen; Chen, Junwu^*

来源：ACS Applied Polymer Materials, 2022, 4(12): 9116-9124.

DOI：10.1021/acsapm.2c01448

• benzotriazole-fused moiety
• narrow band gap
• polymer acceptor
• short-circuit current density
• as-cast
• all-polymer solar cells

High-performance all-polymer solar cells still lag behind their counter-part based on small molecular acceptors. In this work, two polymer acceptors (PYBzT and PYBzDT) involving the fused benzotriazole moiety were developed by polymerizing different electron-donating moieties, thiophene and bithiophene, respectively. Intriguingly, PYBzT showed broad absorption spectra with a lower optical band gap of 1.36 eV than that of the polymer PYBzDT. Moreover, the electron mobility of PYBzT is quite higher than that of PYBzDT even though the pi-pi distance of PYBzT is slightly larger than that of PYBzDT. As a result, PYBzT-based as-cast all-polymer solar cells (all-PSCs) showcase a higher power conversion efficiency (PCE) of 11.2% if compared to that of 8.93% for PYBzDT-based all-PSCs. Remarkably, due to broad absorption coverage, efficient charge separation, and more balanced hole and electron transport, the PYBzT-based device showed a large Jsc of 23.44 mA cm-2, which is one of the highest Jsc in the as-cast all-PSCs. Our results indicate that polymer acceptors involving the benzotriazole moiety are of high potential in efficient as-cast all-PSCs.