Improved V2OX Passivating Contact for p‐Type Crystalline Silicon Solar Cells by Oxygen Vacancy Modulation with a SiOX Tunnel Layer

Abstract Transition metal oxide (TMO) thin films featuring tunable work function, high transmittance, and simple fabrication process are expected to serve as carrier‐selective transport layers for high‐efficiency crystalline silicon ( c ‐Si) solar cells. TMOs are prone to reaction or elemental migration with adjacent materials, which leads to uncontrollable optical and electrical properties. In this work, V 2 O X passivating contact, a promising hole transport layer (HTL) thanks to its high work function, is investigated and implemented in p ‐type c ‐Si solar cells. An ultrathin SiO X tunnel layer is intentionally introduced by UV/O 3 pretreatment to suppress the redox reaction at c ‐Si/V 2 O X interface. Both saturation current density and contact resistance are reduced with the presence of UV‐SiO X due to the well tunned oxygen vacancies in SiO X and V 2 O X thin films. The power conversion efficiency (PCE) based on p ‐Si/UV‐SiO X /V 2 O X /Ag rear contact achieves 21.01% with an increased open‐circuit voltage of 635 mV and fill factor (FF) of 83.25%.