Sol-gel preparation and near-infrared emission properties of Yb3+ sensitized by Mn4+ in double-perovskite La2ZnTiO6

Abstract Yb 3+ /Mn 4+ co-doped La 2 ZnTiO 6 (brief as LZT:Yb 3+ /Mn 4+ ) phosphors with xYb 3+ (x = 0–0.12) and yMn 4+ (y = 0–0.01) doping concentrations have been synthesized via a sol-gel method. X-ray diffraction (XRD) and photoluminescence spectra were employed to characterize the properties of final products. The LZT:Yb 3+ /Mn 4+ material can efficiently convert the short-wavelength sunlight in wide spectral ranges (250–600 nm) into near-infrared emission around 990 nm which matches the higher photosensitivity region of Si-based solar cells. A dipole-dipole interaction plays an important role for the energy transfer process from Mn 4+ to Yb 3+ ions, which has been verified by Dexter's theory. Under the 390 nm excitation, the energy transfer efficiency is 38.6% in the La 1·9 ZnTi 0·998 O 6 :0.1Yb 3+ /0.002Mn 4+ co-doped sample. Due to the effective absorption of Mn 4+ in the visible region and charge transfer transitions (O 2− →Yb 3+ and O 2− →Mn 4+ ) in the UV region for LZT and the efficient energy transfer to Yb 3+ , this material can be developed as spectral convertors to improve silicon solar cell photovoltaic conversion efficiency.