Yttrium Fluoride-Based Electron-Selective Contacts For Crystalline Silicon Solar Cells

The development of dopant-free carrier-selective layer demonstrates the potential to overcome parasitic absorption and doping-related recombination caused by heavy doping to realize both low recombination current density (J(0c)) and low contact resistance (rho(c)) in simplified procedures. In this work, thermally evaporated yttrium fluoride (YF3) films were demonstrated as electron-selective material for c-Si solar cells. The YF3 interlayers have a low work function of 3.1 eV, allowing the lowest rho(c) of 17.8 m Omega.cm(2 )for the n-Si/YF3/Al contacts. N-type Si solar cells based on YF3 for electron-passivated contact were fabricated, reaching an efficiency of 20.8%, an open-circuit voltage of 645 mV, and a fill factor of 80.8%. This indicates the future potential application of dopant-free YF3 electron contact for low-temperature-passivated contact solar cells.