Improving efficiency of perovskite solar cell by using Nb-doped $BaSnO_3$ electron transport layer

Abstract

Understanding electronic structure of electron transport layer (ETL) and light absorbing layer is essential to improve the conversion efficiency of the perovskite solar cell (PSC). Improved efficiency of PSCs was provided by Nb-doped $BaSnO_3$ as ETL by tailoring electronic structure of the $BaSnO_3$ with Nb doping. The Nb-doped $BaSnO_3$ was prepared by a sol-gel method followed by a hydrothermal treatment

the Nb content was varied from 1, 2, and 5 mol%. The X-ray photoelectron spectroscopy and UV-Vis result showed that the Fermi level of $BaSnO_3$ shifted toward the conduction band minimum (CBM) when the Nb content becomes higher. The changes of short circuit current $(J_{SC})$ and open circuit voltage $(V_{OC})$ of PSCs were explained in relation to the electronic structure of the $BaSnO_3$ layer. As a compromise of changes in $J_{SC}$ and $V_{OC}$, the best efficiency of 11.44% was demonstrated by PSCs with 1 mol% Nb-doped $BaSnO_3$.