Synergistic dual-interface modification strategy for highly reproducible and efficient PTAA-based inverted perovskite solar cells

Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA)-based inverted perovskite solar cells (PSCs) are the most efficient device type reported to date. Nevertheless, the high hydrophobicity of PTAA and the nonradiative recombination loss significantly limit the repeatability and the performances of these devices. In this study, polyvinyl oxide (PEO) and tetra-n-propylammonium bromide (TPAB) were introduced to overcome the hydrophobicity of PTAA and the anode and cathode interface nonradiative recombination losses through the synergistic effect of these materials. The results showed that the PEO could dramatically improve the wetting properties of the perovskite precursor on the PTAA surface, correspondingly enhancing the microstructure of the film, eliminating the defects, and enhancing the anode interfacial contact of the device. The performances and performance repeatability of the devices were greatly improved. The ratio of the short-circuited devices decreased from 44.23 % to 0 %, and the average power conversion efficiency (PCE) increased dramatically. In addition, a facile TPAB surface treatment strategy was proposed to reduce the potential threat of PEO introduction to the device stability as well as improve the cathode interface contact problems of the device. Owing to the synergistic effect of the PEO and TPAB, the performance and stability were both enhanced. The highest PCE of 21.62 % was achieved, and the average PCE of TPAB devices could be maintained at 80 % for 298 h (in air, 23 °C, 25 RH%) and 96 % for 217 d (in N2, 23 °C) of the initial PCE value. The synergistic dual-interface modification strategy proposed in this paper lights the way for the preparation of highly reproducible, efficient, and stable PTAA-based inverted perovskite solar cells.