Large Area and High‐Efficiency MXene–Silicon Solar Cells by Organic Enhanced Dispersity and Work Function

2D transition metal carbon/nitrides (MXenes) have lately attracted increased attention in photovoltaic (PV) because of their good optical and electrical properties. MXenes–silicon solar cells as a novel PV device are considered to be a low‐cost strategy for boosting Si‐based device development. Nevertheless, power conversion efficiency (PCE) and large area preparation are limited in their future applications. Here, the solubilization of Ti 2 CT x (T = O, F, OH) MXene multilayer nanosheets is reported and thus the ability of scaled coating of Ti 2 CT x MXene thin films using an organic Nafion polymer solution is enhanced. It is demonstrated that an effect of termination by Nafion to Ti 2 CT x MXene groups (MXene:Nafion) dramatically enhanced the work function of the Ti 2 CT x MXene from 3.96 to 5.17 eV. Due to the excellent passivation ability of the organic Nafion species, the MXene:Nafion increases the effective carrier lifetime of silicon wafers to 2.52 ms compared with unpassivated control (0.03 ms). These results finally contribute to the high PCE of 14.21% of MXene:Nafion–Si solar cell with a large area of 7.29 cm 2 . This work proposes a large area MXene:Nafion–Si heterojunction solar cell with high performance and low cost, which points to the great promise of such a device for future application.