Perovskite solar cells on Sn-doped In2O3 electrodes with artificially controlled (222) preferred orientation

Abstract

Despite the rapid advancements in transparent conductive electrodes (TCEs), most planar-type perovskite solar cells (PSCs) are still fabricated on commercial polycrystalline Sn-doped In2O3 (ITO) electrodes, due to their resulting high conductivity, transmittance, and technological mutuality. However, artificially controlling the preferred orientation of a sputtered ITO electrode through O2 partial pressure can lead to differences in the conductivity, transmittance, and surface morphology of the ITO electrode, as well as in the growth behavior of the NiOx hole transport layer and methylammonium lead iodide (MAPbI3) active layer on the ITO for high-performance planar-type PSCs. Here, we comprehensively compared the electrical, optical, structural, and morphological properties of (222) and (400) artificially preferred ITO electrodes, and we correlated the performances of the PSCs with these differently preferred ITO electrodes. The higher power conversion efficiency (17.82%) of PSCs on (222) preferred ITO electrode than that (7.98%) of PSCs on the (400) preferred ITO electrode could be attributed to the larger grain size of the MAPbI3 active layer on the (222) preferred ITO electrode with low sheet resistance (2.66 Ohm/square) and high optical transmittance (93.47%). This suggests that artificial control of the (222) preferred orientation of sputtered ITO electrode represents a simple method for improving the performance of PSCs with identical perovskite photoactive layer.