Enhanced Performance of Hole-Conductor-Free Perovskite Solar Cells by Utilization of Core/Shell-Structured β-NaYF4:Yb3+,Er3+@SiO2 Nanoparticles in Ambient Air

In this study, hole-conductor-free perovskite solar cells (PSCs) were incorporated with a core/shell-structured upconversion emission material, beta-NaYF4 : Yb3+, Er3+ @SiO2 (NYEY@S) nanoparticles, which led to an excellent performance due to the expanded range of spectral response in ambient air. The advantage of core/shell-structured NYEY@S nanoparticles in PSCs is that they overcome the electron trapping caused by bare beta-NaYF4 : Yb3+, Er3+ (NYEY) nanocrystals. By incorporating NYEY@S nanoparticles into PSCs as an upconvertingmesoporous layer, the PSCs achieve greater conversion efficiency and attain a value of 9.92%, which is 21% higher than that of normal PSCs (only TiO2 nanoparticles as the mesoporous layer). This result indicates that incorporating NYEY@S into PSCs provides a new approach to enhance the photovoltaic performance of PSCs.