Interfacial engineering using ammonia-functionalized MXene in perovskite solar cells

Engineering the morphological and electronic properties for enhanced hole extraction is one of the most crucial routes for achieving high device performance. Interfacial engineering using MXene nanosheets between the absorber and transport layers alters the perovskite film formation and the dynamics of interfacial charge transport. However, the stability of MXenes is a challenge that can be addressed by passivation. Passivation of MXenes by means of functionalization gives rise to unique properties. Despite excellent electrochemical, electrical, and optoelectronic properties, the oxidative degradation of MXenes due to the structural defects limits its stability. Hence passivation of these defect sites on MXenes is required. In this study, neat and ammonia-functionalized MXene is employed at the HTL-active material interface. The 2D MXenes influenced grain growth and optical properties. These hole transport layers (HTLs) have achieved a boost in hole extraction efficiency by aligning band edges, resulting in a notable enhancement in photoluminescence (PL) quenching by 15% and 12%, respectively. The impact of Ti 3 C 2 T x MXenes on current–voltage behaviour, power conversion efficiency (PCE), and the underlying causes were investigated through experimental and simulation-based defect studies. Graphical abstract