Post-annealing-free BaOxFy/LiF-based stack electron-selective contacts for high efficiency crystalline silicon solar cells featuring ultra-low contact resistivity

We developed a stacked BaOxFy/LiF electron selective contact with an ultra-low contact resistivity of 1.4 mΩ·cm2 without any extra annealing activation step. A solar cell with full-area BaOxFy/LiF/Ca:Al alloy contact achieved an efficiency of 20.5%. Moreover, the carrier recombination mechanism for the BaOx-based device was intensively explored by transient photovoltage measurement.