Interfacial modification to improve all-inorganic perovskite solar cells by a multifunctional 4-aminodiphenylamine layer

Abstract

All-inorganic carbon-based perovskite solar cells (PSCs) offer low costs and a favorable balance between stability and power conversion efficiency (PCE). Although bulk perovskites are defect tolerant, the defect-mediated carrier nonradiative recombination at the interface between perovskite and carbon layers limits the device performance and stability. In this study, a new 4-aminodiphenylamine (4-ADPA) interlayer was applied to modify the surface and grain boundaries of CsPbI2Br perovskite films. The 4-ADPA layer passivated defects by binding with undercoordinated lead and halide ions at the surface, resulting in the improved thin film quality, reduced defects, and suppressed carrier recombination. All-inorganic CsPbI2Br PSCs by 4-ADPA passivation achieved a PCE of 11.16% with reduced hysteresis and open-circuit voltage loss. In addition, the 4-ADPA passivation inhibited the degradation of the perovskite films in ambient conditions. After storing in air at 25 °C and 25% relative humidity for 700 h, the unpackaged PSC retains 80% of the original PCE. The all-inorganic PSCs with greatly improved device performance and stability would have great prospects in practical applications.