Fig. 10From: A New Up-conversion Material of Ho3+-Yb3+-Mg2+ Tri-doped TiO2 and Its Applications to Perovskite Solar Cellsa I-V curves of the solar cells under the simulated solar radiation filtered with a band-pass NIR filter (980 ± 10 nm). b IPCE spectra of the solar cells with and without UC-Mg-TiO2Back to article page