Enhanced Electrons Extraction of Lithium-Doped SnO$_{2}$ Nanoparticles for Efficient Planar Perovskite Solar Cells

Hybrid lead halide perovskite solar cells (PSCs) are amongst those efficient solar cell technologies which are developing rapidly. The rapid advancement in PSCs technology is because of favorable properties of perovskite materials and addition of charge selective layers. Here, we report lithium-doped SnO
$_{2}$
electron transport layer (ETL) to improve electrons extraction from the perovskite absorbing layer. The lithium-doped SnO
$_{2}$
not only shows relatively higher conductivity, reduced oxygen-deficient regions, improved oxidation state, but also induces a larger grain size of perovskite films. This leads to an improvement in all related photovoltaic parameters of the methylammonium lead iodide (MAPbI
₃
) planar heterojunction PSCs. The champion device yields a power conversion efficiency of 19.09%. The simple solution and lower annealing processed ETLs are compatible with almost all substrates used in PSCs and other perovskite-based devices.