Effects of the concentration of PbI2 and CH3NH3I on the perovskite films and the performance of perovskite solar cells based on ZnO-TiO2 nanorod arrays

Abstract

To date the research of the effects of the concentration of PbI2 and CH3NH3I in the two-step sequential deposition process on the perovskite films and the performance of the perovskite solar cells (PSCs) based on nanorod arrays is rarely reported. In this paper, the perovskite films and the PSCs based on ZnO-TiO2 nanorod arrays were prepared by two-step sequential deposition method in ambient atmosphere. The effects of the concentration of PbI2 and CH3NH3I solution on the morphology, structure, optical absorption and luminescence properties of perovskite films and cell performance were systematically investigated by using field emission scanning electron microscope, X-ray diffractometer, UV–vis spectrophotometer, fluorophotometer, and photocurrent density-voltage (J-V) curves. The best power conversion efficiency (PCE) of perovskite solar cell reaches 10.38% by using PbI2 with a concentration of 1.0 M and CH3NH3I with a concentration of 0.063 M in ambient atmosphere with a relative humidity of about 40%. The PCE of the device may be further improved by optimizing the density and length of nanorod arrays and using glove box. These results provide valuable information for preparing more efficient all-solid-state PSC based on nanorod arrays.