Comparison of ITO, In2O3:Zn and In2O3:H transparent conductive oxides as front electrodes for silicon heterojunction solar cell applications

In this study, we presented a comparative investigation on the electrical, optical, and structural properties of three types of transparent conductive oxides (TCOs), including tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO) and hydrogen-doped indium oxide (In2O3:H or IO:H) films. Post annealing treatment (195 degrees C, 30 min, and air ambient) was performed to optimize the material characteristics of the TCOs. Further, we evaluated the applications of ITO, IZO and IO:H films in silicon heterojunction (SHJ) solar cells. The effects of material characteristics of TCOs on the device performance were studied. It was found that the ITO films with a low resistivity contributed to the fill factor of the SHJ solar cells, while the IZO films showed obvious advantage in open-circuit voltage of the cells, with the best value of 0.736 V. Comparing with ITO and IZO films, the resulting IO:H films feature both highest carrier mobility (with the best value of 100 cm(2)/V.s) and band gap values after annealing, which contribute to the short-circuit current density of 39.18 mA/cm(2). The SHJ solar cell with IO:H films as front TCO layer, showed a large scale (153.4 cm(2)) power conversion efficiency of 21.13%, showing an obvious enhancement compared to the ITO and IZO counterparts. (C) 2017 Elsevier Ltd. All rights reserved.