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 (ρc) 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 ρc of 17.8 mΩ·cm2 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.