Compound/silicon heterojunction (SCH) solar cells have been widely studied due to the low parasitic absorption of the window layer, high short-circuit current, and simple preparation process. So far, most reported SCH solar cells are small-area devices. By depositing MoO x hole transport layer using hot-wire oxidation-sublimation deposition technique and employing a front-contact back-junction cell architecture, the large-area SCH solar cells are successfully fabricated on M6 (166 mm) n-type silicon wafers. Indium cerium oxide (ICO) film with the optimal thickness of about 110 nm is inserted between MoO x and Ag. The ICO/Ag stack functions well as a back reflector and is beneficial for increasing the short-circuit current density, reducing the contact resistance, and improving the device stability. A power conversion efficiency of 21.59% is achieved on the champion SCH solar cell with the device area of 274.15 cm 2.

In this work, high quality hafnium and hydrogen co-doped In 2O 3 (IHfO:H) transparent conductive films are developed via a reactive plasma deposition (RPD) technique followed by air atmosphere annealing. Crystallinity, valence states, and opto-electronic properties of the IHfO:H films under different H 2 concentration (0-1.5 %) and different annealing temperature (100-250 °C) are systematically investigated. The effects of hydrogen doping and annealing temperature on the properties of the IHfO:H films are discussed. The high average transmittances (400-800 nm: 87.92 %; 800-2300 nm: 86.68 %), a sheet resistance of 27.53 Ω/□, and a Hall mobility of 102.92 cm 2V −1s −1 are achieved on the optimized IHfO:H thin film fabricated using 0.8 % H 2 concentration with a 200 °C annealing temperature. Finally, the IHfO:H films are applied to the bifacial silicon heterojunction (SHJ) solar cells to serve as the front-side transparent electrode. The significant improvement in the long wavelength spectral response compared to the control SHJ device with an indium tin oxide (ITO) front-side transparent electrode leads to an increase of about 0.3 % in the efficiency and an efficiency of over 25 % is achieved on the SHJ solar cell with an IHfO:H front-side transparent electrode.