Cerous Fluoride Dopant‐Free Electron‐Selective Contact for Crystalline Silicon Solar Cells

Dopant‐free carrier‐selective contacts have drawn intensive attention for efficient crystalline silicon (c‐Si) photovoltaics due to the low‐temperature simple process and better carrier selectivity. By incorporating a thermally evaporated dielectric film cerium fluoride (CeF 3 ) as the electron transport layer (ETL) between a c‐Si(n) and aluminum (Al) electrode, higher conversion efficiency of the crystalline silicon solar cell is obtained, which is 21.27% compared to 16.89% of a reference cell without CeF 3 . The insertion of an ultrathin CeF 3 ETL helps in alleviating the strong Fermi‐level pinning at the interface, leading to better electron transport with a low contact resistivity of 10.96 mΩ cm 2 . The morphology and element distribution of the interface are also investigated by high‐resolution transmission electron microscopy (HRTEM). The primary results demonstrate that the utilization of kinds of lanthanide fluorides, including CeF 3 , offers a good choice for efficient and cost‐effective electron‐selective contacts for optical–electrical devices.