Construction of V2Ox/Si heterojunction and carrier-assisted collection for high-efficiency silicon solar cells

Abstract

Vanadium oxide (V2Ox) is a typical wide-bandgap transition metal oxides semiconductor, with excellent hole selective contact performance by forming heterocontact with Si. Nevertheless, the poor lateral conductivity of V2Ox film weakens the carrier collection ability and limits the performance of solar cells. Here, V2Ox/Si heterojunction was clearly demonstrated and achieved superior carrier separation. Meanwhile, the carrier collection efficiency was enhanced through PEDOT:PSS for accomplishing the power conversion efficiency improvement. The V2Ox/Si heterojunction was confirmed via Kelvin probe force microscopy with a potential difference in the junction area, and an appropriate work function of V2Ox film was acquired under low annealing temperature. Numerical simulations also synergistically reveal the role of V2Ox/Si heterojunction, and the high band bending at Si surface was 0.84 eV, which further promotes carrier separation. Finally, the V2Ox/Si heterojunction solar cell was fabricated with PEDOT:PSS and showed a power conversion efficiency of 12.64%, which was 6 times higher than basic V2Ox/Si heterojunction solar cell. These results provide a new reference for fabricating low-cost, technically simple, and high-efficiency solar cells.