Luminescence Properties And Energy Transfer Process In Yb³⁺-actived Oxysalt Materials

The Yb3+:2F5/2â†'2F7/2emission can be absorbed by silicon solar cells without signifiently thermalization losses. It’s considered that fluorescent powder doping with Yb3+is one solution to reduce the thermal loss by modifying solar spectrum. In recent years, much work has been conducted on searching more practical conversion material, and study the downconversion mechanisms. However, the research on the energy transfer efficiency is still limited.In these paper, we prepared Oxyacid salt doping with Yb3+and the luminescence properties was studied in detail. We examined energy transfer efficiency between Ln3+(Ln3+=Pr3+,Tb3+) and Yb3+ions.The main researches are as follows:1. GdBO3:Pr3+and GdBO3:Pr3+, Yb3+samples were prepared by solid state reaction at high temperature. The XRD patterns, excitation spectra and emission spectra in the vis-NIR range of the obtained samples were studied in detail at room temperature. The emission of2F5/2â†'2F7/2(980nm) of Yb3+was observed under excitation at446nm, indicating the occurrence of the energy transfer from Pr3+to Yb3+. The fluorescence intensities varied with different Yb3+doping concentrations. Luminescence decay curves of Pr3+:3Po level were recorded as a function of the Yb3+concentrations and energy transfer efficiency was also calculated. Based on Inokuti-Hirayama model, the energy transfer type from Pr3+to Yb3+was derived to be electric dipole-dipole interaction.2. YAG:Pr3+and YAG:Pr3+, Yb3+samples were prepared by coprecipitation method. The XRD patterns, excitation spectra and emission spectra in the vis-NIR range of the obtained samples were studied in detail at room temperature. The efficient energy transfer from Pr3+to Yb3+was observed. The fluorescence intensities varied with different Yb3+doping concentrations. Luminescence decay curves of Pr3+:3Po level were recorded as a function of the Yb3+concentrations and energy transfer efficiency was also calculated. The study shows different host influence the energy transfer efficiency from Pr3+to Yb3+.3. The energy transfer process from Tb3+to Yb3+in GdBO3was investigated. The excitation spectra and emission spectra in the vis-NIR range of the obtained samples were studied in detail at room temperature. The emission of2F5/2â†'2F7/2(980nm) of Yb3+was observed under excitation at355nm, indicating the occurrence of the energy transfer from Tb3+to Yb3+.It was assumed that the energy transfer mechanism was different between Pr3+-Yb3+and Tb3+-Yb3+.4.In YAG:Tb3+, Yb3+, the energy transfer process among Tb3+and Yb3+were investigated. Based on steady state spectra, energy transfer from Tb3+to Yb3+was observed. The fluorescence intensities varied with different Yb3+doping concentrations.