Multifunctional Optimization of MXene for Enhanced Comprehensive Performance of Crystal Silicon‐MXene Back‐Heterojunction Solar Cells

Enhancing the cost-performance ratio is a fundamental objective for the advancement of the photovoltaic sector. In this context, the development of innovative solar cells that offer a straightforward device configuration but high performance is arguably the most crucial element. Herein, an undoped back-heterojunction crystalline silicon (c-Si) solar cell is endeavored to be crafted by simply drop-casting a Ti₃C₂T_x MXene ethanol colloidal solution onto the backside of an n-type c-Si (n-Si) wafer. Leveraging the good electrical property and stability, as well as the adjustable work function of MXene treated by europium trifluoromethanesulfonate (Eu(OTF)₃), the elementary Ag/ZnO/n-Si/MXene/Ag solar cell delivers an impressive power conversion efficiency (PCE) of 12.5%. Moreover, the deposition of a SiO₂ passivation layer through a simple self-developed electrochemical method increases the PCE further to 13.5% by ameliorating the interfacial contact between MXene and n-Si. Moreover, this unencapsulated solar cell exhibits improved stability, compared to the control device without Eu(OTF)₃ treatment and SiO₂ passivation.