Effects Of Doping Concentration On Spectroscopy Properies Of Er³⁺ And Er³⁺/Yb³⁺ Doped Oxyfluoride Glasses

Recently, rare earth ions doped upconversion luminescence (UCL) crystals and glasses materials have been obtained extensive attentions, especially the outstanding applied ability for visible light, which emitted via infrared light excitation. The rare earth ions doped solid luminescent materials have bright application prospects in the fields such as optical data storage, medical diagnostics, sensor, color display, etc. In this paper, Er3+ single doped and Er3+/Yb3+ codoped oxyfluoride glasses were prepared by high temperature melt-quenching method, and concentration dependent spectroscopy properies were analyzed. More details can be described as follows:(1) Er3+ doped oxyfluoride glasses were prepared by a facile melt-quenching technique, and the absorption spectra of all the samples with various Er3+ concentrations were measured. The J-O paramenters Qλ were calculated using the Judd-Ofelt theory, and the effect of Er3+ concentrations on the optical transition properties and the characteristics of oxyfluoride glasses were discussed. The UC spectra were measured by 980 nm and 808 nm excitation at room temperature, and strong green emissions (525 nm and 545 nm) and red emissions (655 nm) were clearly observed, which were corresponding to the transitions 2H11/2â†'4I15/2,4S3/2â†'4I15/2 and 4F9/2â†'4I15/2 of Er3+ respectively. The green and red UC emissions were both attributed to two-photon process by analyzing the relationship between the pumped current of laser and the UCL intensity. Moreover, the reason for concentration quenching of the samples was analyzed, and the cross relaxation channels were summarized.(2) Er3+/Yb3+ codoped oxyfluoride glasses were prepared by a facile melt-quenching technique, and the absorption spectra of all the samples with various Yb3+ concentrations were measured. The UCL spectra were obtained by using 980 nm fiber laser as the excitation light source. The dependences of the UCL intensities on the pumped current were analyzed, and it was found that the red and the green UC emissions both can be attributed to two-photon UC processes. In addition, it was found that, with the increase of Yb3+ concentration, the UCL intensity increased first and then decreased. This concentration quenching behavior results from the energy transfer from Er3+ to Yb3+. Moreover the strongest UCL intensity can be obtained when the doping concentration molar ratio of Yb3+ to Er3+ was 10 to 3.