Power conversion efficiency of 25.26% for silicon heterojunction solar cell with transition metal element doped indium oxide transparent conductive film as front electrode

Abstract In this paper, to improve the power conversion efficiency ( E ff ) of silicon heterojunction (SHJ) solar cells, we developed the indium oxide doped with transition metal elements (IMO) as front transparent conductive oxide (TCO) layer combined with microcrystalline silicon ( μ ‐Si:H(n + )) for SHJ solar cell. The optical and electrical properties as well as structures of hydrogenated IMO (IMO:H) films were studied and compared to conventional indium tin oxide (ITO) film. Such IMO:H films have high carrier mobility over 70 cm 2 /V·s, high transmittance, and low free carrier absorption, which leads to a high short circuit current density exceeding 40 mA/cm 2 . In addition, the low sheet resistance and contact resistivity of the IMO:H films contribute to the high fill factor of the solar cell. The average E ff of solar cells with IMO:H + μ ‐Si:H(n + ) is improved by 0.4% compared with that of the solar cells with ITO + a‐Si:H(n + ). Finally, a certified efficiency up to 25.26% (total area, 274.5 cm 2 ) was achieved.