A facile co-precipitation method for synthesis of Zn doped BaSnO3 nanoparticles for photovoltaic application

BaSnO3 (BSO) is a widely used electron transporting layer (ETL) in solar cells due to its wide bandgap and high mobility. BSO was modified for better optical and electronic properties by doping Zn atoms by a facile co precipitation method. The alteration in structural, optical, and electronic properties of BSO on doping with different concentrations of Zn (0.5 mM, 1 mM) was studied. The Optimum bandgap of Zn doped BSO samples and high optical transparency makes it a suitable ETL in perovskite solar cells (PSCs). PSCs were fabricated using BSO, 0.5 mM Zn-BSO (0.5BSO), and 1.0 mM Zn-BSO (1BSO) as an electron transport layer (ETL), vapor deposited MaPbI3 as the absorber, and CuSCN as the hole transporting material to demonstrate the functioning of the Zn doped BaSnO3 as ETL in PSCs. BSO exhibited a bandgap of 3.36eV, whereas 0.5 mM Zn-BSO and 0.1 mM Zn-BSO exhibited 3.44eV and 3.72eV, respectively, and the in the conduction band edges were analyzed by Mott-Schottky analysis. The particle sizes increased from 9.7 nm to 11.7 nm with increment in doping concentration. The fabricated devices yield a promising power conversion efficiency (PCE) of 3.9% with an open-circuit voltage (VOC) of 0.80 V and current density (JSC) of 9.8 mA/cm(2) for 0.5 mM Zn-BSO samples. In contrast, the PSCs fabricated with BSO showcased lesser PCE (3.0% with VOC of 0.74 V and JSC of 8.4 mA/cm(2)). The electron lifetime was calculated using impedance spectroscopy, and 0.5BSO exhibited a higher electron lifetime (9.3 x 10(-7) ns) when compared to BSO and 1.0BSO, indicating reduced recombination and better charge extraction.