Recent review of interfacial engineering for perovskite solar cells: effect of functional groups on the stability and efficiency

At present, perovskite solar cells (PSCs) have the highest efficiency record (25.7%) among next-generation solar cells. Therefore, currently, various studies are ongoing to improve the efficiency and stability of PSCs for commercialization. The stability of PSCs is affected by the perovskite's sensitivity to defects in the perovskite layer/charge transport layer (CTL) interface, heat, UV light, and humidity. Interfacial engineering can be used to improve the stability of PSCs by applying it to the perovskite layer/CTL interface to reduce interface defects, which induce perovskite degradation. In addition, interfacial engineering causes reduced non-radiative recombination due to the passivation of the surface defects, improved charge carrier transport through band alignment, and increased stability due to the hydrophobicity of the interfacial material. Thus, in this study, the effect of major interfacial materials functional groups on the stability and efficiency of PSCs is reviewed. First, the factors (moisture, thermal, light, oxygen, electric field) that induce perovskite degradation and are directly related to the stability of PSCs are outlined. Subsequently, the relationship between the main interfacial materials functional groups (carboxyl group, amine group, aromatic ring group, 2D perovskite) and performance (efficiency and stability) of PSCs is summarized. Finally, the application prospects of using interfacial engineering to improve the stability of PSCs is analyzed.