Polymeric Surface Modification of NiOx-Based Inverted Planar Perovskite Solar Cells with Enhanced Performance

Interfacial engineering has been considered one of the most effective methods for further enhancing the performance of perovskite solar cells. Herein a facile but effective interfacial engineering method of modifying NiOx coated substrate by PTAA is demonstrated for inverted planar perovskite solar cells. The surface modification by polymeric PTAA could effectively tailor the quality of perovskite absorber layer with larger grain size and better crystallinity by controlling wettability of NiOx surface with varied thickness of hydrophobic PTAA. The improvement of Jsc was ascribed to the improved perovskite film quality with reduced trap state densities. By EIS and TRPL analysis, it was also confirmed that PTAA modification significantly facilitated interfacial charge transfer at the interface between perovskite and PTAA/NiOx due to the gradient band alignment. As a consequence, the highest power conversion efficiency of 17.1% together with negligible hysteresis effect was achieved from planar perovskite so...