Efficient Near-infrared Down-conversion Phosphor of Ce3+/Yb3+ Co-doped La3Ga5SiO14 and Its Spectral Structural Modulation

A series of near-infrared (NIR) down-conversion phosphors of La3Ga5SiO14 (LGS):Ce3+/Yb3+ were synthesized via high-temperature solid-state reaction. Under excitation at 345 nm, the phosphors show strong NIR emission around 978 nm, which matches well with the optimal spectral response of crystalline silicon (c-Si) solar cells. The emission spectra and decay curves were used to demonstrate the energy transfer from Ce3+ to Yb3+. The energy transfer mechanism was discussed in detail, indicating that the energy transfer from Ce3+ to Yb3+ is dominated by a single photon process, and the energy transfer efficiency is up to 51%. In addition, La3Ga5-zAlzSiO(14) (z = 0, 1, 2, 3):Ce3+/Yb3+ were also synthesized. The NIR emission intensity of La(3)Ga(2)Al(3)SiO(14:)1%Ce3+/5%Yb3+ is 4.6 times that of LGS:1%Ce3+/5%Yb3+, and the thermal relaxation was used to explain this phenomenon. The results show that La3Ga5-zAlzSiO(14) (z = 0, 1, 2, 3):1%Ce3+/5%Yb3+ phosphors have the potential to increase the conversion efficiency of c-Si solar cells.