Improvement of the photovoltaic performance of perovskite solar cells by modification of electron transport layer using Mg-doped Tio2, Cs2Co3, and bilayer Mg-doped Tio2/Cs2Co3

Abstract

In this literature, the enhancement of electron transport layers (ETLs) in perovskite solar cells (PSCs) by modifying Tio2 thin layers with Magnesium (Mg) and Cesium Carbonate (CS2CO3) was studied. We aimed to modify lattice and surface properties for improved ETL performance. The impact of various doping ratios and coating speeds using UV–visible spectra, scanning electron microscope (SEM), and electron chemical impedance spectrum (EIS) were analyzed. An optimized thin film, 1.5% Mg-doped Tio2, was identified with increased transmission, wider band gap, enhanced conductivity, and reduced resistivity. The bilayer Mg-doped Tio2/CS2CO3 structure shows significant surface modifications via SEM. The optimized thin films including pure Tio2 (60 mm/s), Mg-doped Tio2 (1.5%), Tio2-CS2CO3 (60 mm/s), and Mg-doped Tio2/CS2CO3 were integrated into perovskite solar cells (PSCs), achieving superior efficiency. Introducing Magnesium (Mg) dopants to TiO2 thin films enhanced the band gap energy, influencing energy levels within. This optimized the alignment of energy states at the TiO2-perovskite interface. As a result, the open-circuit voltage (Voc) of the perovskite solar cells improved, reflecting the potential difference between illuminated electrons and the external circuit. This enhancement, due to Mg doping, facilitated efficient charge carrier separation and extraction, boosting overall cell performance. Bilayer Mg-doped Tio2/CS2CO3 showed the best performance with open-circuit voltage (Voc), short-circuit density (Jsc), fill factor, and power conversion efficiency (PCE) 0.98 v, 16.02 mA/cm2, 59%, and 9.37% respectively.