High Efficiency and Stability of Inverted Perovskite Solar Cells Using Phenethyl Ammonium Iodide-Modified Interface of NiO_x and Perovskite Layers

Hole transport layer NiO_x-based inverted perovskite solar cells (PSCs) have advantages of simple fabrication, low temperature, and low cost. Furthermore, the p-type NiO_x material compared to that of typical n-type SnO_x for PSCs has better photostability potential due to its lower photocatalytic ability. However, the NiO_x layer modified by some typical materials show relatively simple functions, which limit the synthesized performance of NiO_x-based inverted PSCs. Phenethyl ammonium iodide (PEAI) was introduced to modify the NiO_x/perovskite interface, which can synchronously contribute to better crystallinity and stability of the perovskite layer, passivating interface defects, formed quasi-two-dimensional PEA₂PbI₄ perovskite layers, and superior interface contact properties. The PCEs of PSCs with the PEAI-modified NiO_x/perovskite interface was obviously increased from 20.31 from 16.54% compared to that of the reference PSCs. The PSCs with PEAI modification remained 75 and 72% of the original PCE values aging for 10 h at 85 °C and 65 days in a relative humidity of 15%, which are superior to the original PCE values (47 and 51%, respectively) for the reference PSCs. Therefore, PSCs with the PEAI-modified NiO_x/perovskite interface show higher PCEs and better thermal stability and moisture resistance.