We report a simple and effective method for producing lanthanide ion-doped lithium-fluoride-based nanocrystals (YLiF4). We utilized those nanoparticles for up-conversion in fabricated perovskite solar cells. The obtained results shows that the up-conversion YLiF4:Yb, Er nanoparticles improve alignment of energy levels at interface between titanium dioxide and perovskite layer. This increases power conversion efficiency of fabricated perovskite solar cells from 19.45 % to 21.32 %. To enhance comprehension of the recombination mechanism and its correlation with the conduction band offset and defects, device models are additionally integrated into the SCAPS simulator. Subsequently, the obtained J-V simulation outcomes exhibit a favorable concordance with the experimental observations.