Ternary Metal Oxides based Electron Transport Layers for Perovskite Solar Cells /

Abstract

Perovskite solar cells (PSCs) have acquired popularity owing to their high efficiency, ease of fabrication, and affordability. Within this context, there has been a considerable focus on the development of electron transport layers (ETLs) for highly efficient planar photovoltaic devices. This study investigates the potential of zinc-tin based ternary metal oxide ETLs for their application in planar PSCs. To achieve this, the study employed solution-processed method to fabricate three types of ETL films: crystalline zinc stannate (Zn2SnO4), amorphous zinc-tin oxide (ZTO), and a bilayer film composed of Zn2SnO4 and ZTO. The structural, morphological, and optoelectronic properties of these films were thoroughly examined. X-ray diffraction (XRD) and scanning electron microscopy (SEM) images showed enhanced crystallite size and better surface morphology of perovskite films deposited on bilayer ETL. These ETLs exhibited uniform coverage and high transmittance of up to 90% in the visible spectrum with a band gap range from 4.14 eV for ZTO ETL to 4.29 eV for bilayer ETL. Whereas Photoluminescence studies and Hall effect measurements revealed superior charge extraction, an improved charge carrier mobility (21.84 cm2V-1s-1) and enhanced n-type conductivity in the bilayer ETL. Moreover, the contact angle analysis of the perovskite layer deposited on the bilayer ETL demonstrated increased resistance to moisture erosion, as indicated by the contact angle of 52.20. This finding is particularly significant considering the detrimental effects that moisture can have on the performance of PSCs.