Controlling Surface Morphology of Ag-doped ZnO as a Buffer Layer by Dispersion Engineering in Planar Perovskite Solar Cells

Abstract

In recent years, the power conversion efficiency (PCE (%)) of perovskite solar cells (PSCs) has improved to over 26%. For improving the photovoltaic properties of PSCs, several materials for the electron transport layer (ETL) have been investigated. Zinc oxide (ZnO) has been a significant material studied as an ETL due to its high electron mobility and optical transparency in PSCs. With different deposition methods, ZnO ETL can be processed at low temperatures. Based on several studies, metal-doped ZnO can facilitate electron transfer, thereby improving the performance of un-doped ZnO ETL-based PSCs. Here, to improve the PCE (%) and long-term stability of un-doped ZnO ETL-PSCs, silver (Ag)-doped ZnO 1wt.% as a buffer layer is examined. In this paper, with the addition of an organic solvent (ethanol) to the dispersion of Ag-doped ZnO 1 wt.% nanoparticles (NPs) in deionized (DI) water, the morphology of the buffer layer (Ag-doped ZnO 1 wt.%) can be controlled. This approach focuses on reducing the wettability of the ETL and enhancing the stability of un-doped ZnO ETL-PSCs. According to the results, the preparation of Ag-doped ZnO 1wt.% film as a buffer layer by NPs dispersing in H2O-ethanol mixtures leads to the formation of high-quality perovskite with low defect levels, reducing the recombination rate, and long-term stability of un-doped ZnO ETL-PSCs in ambient conditions. Corresponding author: k_samavati@iau-tnb.ac.ir (Katayoon Samavati).