A comparative study of o,p-dimethoxyphenyl-based hole transport materials by altering pi-linker units for highly efficient and stable perovskite solar cells

作者：Li, Xing; Cai, Molang; Zhou, Zhongmin; Yun, Kang; Xie, Fengxian; Lan, Zhang; Hua, Jianli^*; Han, Liyuan^*

来源：Journal of Materials Chemistry A, 2017, 5(21): 10480-10485.

DOI：10.1039/c7ta02556d

• HALIDE PEROVSKITE
• HIGH-PERFORMANCE
• SENSITIZERS

Two easily synthesized o,p-dimethoxyphenyl-based hole transport materials (HTMs) containing biphenyl (HL-1) and carbazole (HL-2) in the pi-system, respectively, have been designed and studied for perovskite solar cells (PSCs). A higher efficiency of 18.34% for the HL-2 based device was obtained compared to that of HL-1 showing a lower efficiency of 16.14%. A small hysteresis was also observed in the HL-2 based device while the HL-1 based device displayed a significant hysteresis. As a carbazole unit has a stronger electron-donating ability than biphenyl, HL-2 shows a higher hole mobility. The steady-state photoluminescence characteristics confirm that HL-2 can efficiently extract charge carrier at the perovskite/HTM interface rather than HL-1. Meanwhile, a compact HL-2 film without pin-holes effectively suppressed the non-radiative recombination at the interface, resulting in the improvement of the fill factor and open voltage. Most importantly, the steric hindrance due to the long hexyl chain of HL-2 could restrain the halogen migration from the perovskite to the Ag electrode. Thus, the HL-2 based device without encapsulation showed an advanced thermal stability at 85 degrees C after storing for 100 h compared to the HL-1. These results indicate that the o, p-dimethoxyphenyl unit is a promising alternative to develop small molecular HTMs for highly efficient and stable PSCs.

• 出版日期2017-6-7
• 单位华东理工大学