Low‐Cost Tin Oxide Transparent Conductive Films for Silicon Heterojunction Solar Cells

Abstract Indium‐based transparent conductive oxide (TCO) films are widely used in various photoelectric devices including silicon heterojunction (SHJ) solar cells. However, high cost of indium‐based TCO films is not conducive to mass production of the SHJ solar cells. A variety of indium‐free or indium‐less TCOs are explored and utilized presently. Here, SnO_x films are deposited by reactive plasma deposition (RPD) with metal tin as the evaporation source. The metal‐reaction deposited SnO_x films feature low resistivity (<2 × 10⁻³ Ω cm), high mobility (35.93 cm² V⁻¹ S⁻¹), and wide optical bandgap (3.64 eV). A power conversion efficiency (PCE) of 25.33% is achieved on the champion SHJ solar cell using the metal‐reaction deposited SnO_x as the back TCO layer, which indicates the application potential of the metal‐reaction‐deposited SnO_x as a low‐cost substitute for In‐based TCOs in SHJ solar cells and other photoelectric devices.