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

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, V2OX 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 SiOX tunnel layer is intentionally introduced by UV/O3 pretreatment to suppress the redox reaction at c‐Si/V2OX interface. Both saturation current density and contact resistance are reduced with the presence of UV‐SiOX due to the well tunned oxygen vacancies in SiOX and V2OX thin films. The power conversion efficiency (PCE) based on p‐Si/UV‐SiOX/V2OX/Ag rear contact achieves 21.01% with an increased open‐circuit voltage of 635 mV and fill factor (FF) of 83.25%. Transition metal oxides (TMOs) are expected to serve as carrier‐selective transport layers for high‐efficiency crystalline silicon (c‐Si) solar cells. However, redox reactions or elemental migration at the c‐Si/TMO interface tend to degrade the device performance. In this work, an ultra‐thin SiOX tunnel layer was intentionally introduced to suppress the redox reaction at c‐Si/V2OX interface, demonstrating an efficiency up to 21.01%.