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 (Eff) 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 cm2/V·s, high transmittance, and low free carrier absorption, which leads to a high short circuit current density exceeding 40 mA/cm2. 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 Eff 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 cm2) was achieved.