Wide spectral response perovskite solar cells mixed with NaGdF4:Yb3+, Er3+@NaGdF4:Eu3+ core-shell rare earth nanoparticles

Abstract In this study, NaGdF4:Yb3+, Er3+@NaGdF4:Eu3+ (NGEY@NGE) core-shell rare earth nanoparticles are prepared by a simple hydrothermal method. After testing, the emission peaks are observed at 415, 525, 540 and 660 nm with an excitation light of 980 nm due to the up-conversion luminescence from rare-earth nanoparticles. Under light excitation at 395 nm, the rare-earth nanoparticles undergo down-conversion luminescence with emission peaks at 590, 610 and 695 nm. The resulting nanoparticles are introduced into the TiO2 mesoporous layer of hole-conductor-free perovskite solar cells (PSCs) based on carbon counter electrodes to broaden the spectral response of the cells from the visible range to the near-infrared and near-ultraviolet regions, which can guarantee a high light absorption efficiency and corresponding accelerated generation of electron-hole pairs. The results suggest that the mixing of NGEY@NGE nanoparticles into mesoporous TiO2 layer improves the power conversion efficiency of PSCs to 14.21%, which is 10.6% higher than that of the control cells, which can pave an effective way to improve the performance of PSCs with a broadened response range.