Improving stability and efficiency of PTAA-based inverted perovskite solar cells through a guest strategy†

Although poly[bis(4-phenyl) (2,4,6-trimethylphenyl)amine] (PTAA) has been extensively investigated as a hole transport material, its performance regarding stability and efficiency still encounters challenges. In this study, through the introduction of a novel guest molecule BQ-BO, the energy level configuration, hole transport, and interface passivation of PTAA have been significantly enhanced. The large conjugated electron-deficient core and methoxy-substituted triphenylamine arm structure of BQ-BO not only optimize the HOMO energy level but also enhance the hole mobility and conductivity, attaining a photoelectric conversion efficiency of 21.81%. It also exhibited outstanding thermal stability, maintaining an initial efficiency of 90% after 1000 hours of continuous heating at 85 °C, in contrast to a pure PTAA-based device whose efficiency dropped to 70% after 400 hours.