Luminescence and Tm3+-to-Dy3+ energy transfer in TeO2:ZnO glass under NIR/UV excitation

A series of Tm3+/Dy3+ co-doped TeO2:ZnO glass samples were synthetized via fusion method and frequency up- and down-conversion (FUC and FDC) luminescence properties was investigated. A characterization through Raman spectrum and optical absorption of the glass host was first performed, followed by optical absorption and excitation spectra of the Tm3+/Dy3+ doped glass samples. Multi-wavelength light emission was observed in the blue (455 and 480 nm), yellow (580 nm), red (655 nm), and NIR (750, 800, 1400, and 1600 nm) regions, generated via up- or down-conversion, exploiting either NIR (1000–1240 nm) or UV (355 nm) excitation sources, respectively. The excitation routes of both FUC and FDC were proposed. The quasi-resonant overlap of Tm3+ and Dy3+ absorption, excitation, and luminescence spectra in the NIR and UV-VIS spectral regions led to efficient Tm3+-to-Dy3+ energy-transfer processes (Tm3+ [3F4] + Dy3+ [6H15/2] → Tm3+ [3H6] + Dy3+ [6H11/2], Tm3+ [1G4] + Dy3+ [6H15/2] → Tm3+ [3H6] + Dy3+ [4F9/2], and Tm3+ [3H4] + Dy3+ [6H15/2] → Tm3+ [3H6] + Dy3+ [6F5/2]). Time resolve fluorescence confirm Tm3+ ions as donors in the energy-transfer mechanism. The dependence of the luminescence and efficiency of the energy-transfer process upon concentration was evaluated using conventional rate equations. •Multicolor luminescence in blue/yellow/red/NIR in Tm3+-Dy3+ codoped TeO2:ZnO glass.•Frequency up- and down-conversion using multiwavelength NIR and UV pump sources.•Strong quench of Tm3+ luminescence in the presence of small amounts of Dy3+.•Excitation, absorption, and lifetime indicated the possible energy-transfer routes.•Rate equations applied to describe the behavior of Tm3+-Dy3+ codoped samples.