Enhancement of short-circuit current density in silicon heterojunction solar cells by hydrogenated multiple-doped In2O3 thin films

Boosting short-circuit current density (JSC) is crucial to enhance the power conversion efficiency (PCE) of silicon heterojunction (SHJ) solar cells. Herein, hydrogenated W, Mo, Ti, Zr, and Ga-doped indium oxide (IMO:H) films are explored and the structural and optical-electrical characteristics were optimized with the gas flow rate ratio of hydrogen and total gas flow rate. IMO:H films exhibit preferential orientation growth in <100> direction and a distinct shift to higher 2θ with the addition hydrogen is observed due to the size mismatch between doped ions and In ions. Furthermore, the carrier concentration of IMO:H films is decreased due to the substitution of oxygen vacancies by hydrogen, leading to the decrement of free carrier absorption and a 1.25%abs increase of effective total transmittance is obtained in the region from 600 to 1200 nm. Additionally, the mobility of IMO:H films enhances to 67.31 cm2V−1s−1 with optimized resistivity of 2.59 × 10−4 Ω cm ascribing to the reduction of ionized impurity scattering centers provided by oxygen vacancies. When using IMO:H films as rear electrode in industrial solar cells, a 0.35 mA/cm2 absolute increase of average JSC and a 0.33%abs increase in average fill factor is acquired, respectively. Finally, an average PCE gain of 0.18%abs is come through and the champion cell shows PCE of 23.81 %. This work clearly interprets the functions of hydrogen in IMO:H films and offers a valid guidance to optimize of high-efficiency SHJ solar cells.