On radiative and non-radiative decay times in the weak coupling limit

Near-infrared luminescence of Er3+ in MoO3/WO3 modified tellurite glass

In this work, the network structure of Er3+ doped tellurite glass was modified by incorporating MoO3/WO3 oxides and the effect of the structural modification on the near-infrared luminescence properties of Er3+ was investigated. The examination of fluorescence spectrum reveals that partial substituting TeO2 with MoO3/WO3 in the composition significantly enhances both the emission intensity and the FWHM (full width at half maximum) of the 1.53 μm band, and the improved local environment around Er3+ ions and phonon energy of glass host are considered to be responsible for these results. The XRD pattern, Raman spectrum and Judd-Ofelt intensity parameter disclosed the changes in network structure and phonon energy, the DSC curve showed an improvement in thermal stability, and fluorescence decay curve displayed the increase of Er3+ lifetime at the 4I13/2 level, all of these indicated the positive effect of MoO3/WO3 addition on the near-infrared luminescence properties of Er3+.

Theoretical and Experimental Investigation of the Electronic Propensity Rule: A Linear Relationship between Radiative and Nonradiative Decay Rates of Molecules

The electronic propensity rule, which suggests a proportional relationship between radiative and nonradiative electronic coupling elements in fluorescent molecules, has been postulated for some time. Despite its potential significance, the rule has not been rigorously derived and experimentally validated. In this work, we draw upon the theoretical framework established by Schuurmans et al. for the relation between the radiative and nonradiative electronic coupling elements of the rare earth metal in the crystal at low temperature and extend their approach to the fluorescent molecules under external electric field perturbation at a fixed energy gap and varied temperatures, with a further single-electron approximation (Schuurmans, M. F. H., et al. Physica B & C 1984, 123, 131-155). We obtained a linear relation between the radiative decay rates and nonradiative decay rates for internal conversion, which is verified by experimental data from two types of dextran-dye complexes and the light-harvesting antenna complex in photosynthetic bacteria.

Improved 2 µm broadband luminescence in Tm3+/Ho3+ doping tellurite glass

Tm³⁺/Ho³⁺ doping tellurite glasses (TeO₂-ZnO-La₂O₃) were prepared by applying melt-quenching technique, and the ∼2.0 µm band luminescence characteristics were examined. A broadband and relatively flat luminescence at 1600 to 2200 nm was observed in the tellurite glass co-doped by 1.0 mol% Tm₂O₃ and 0.085 mol% Ho₂O₃ under the excitation of 808 nm laser diode (LD), which is the result of spectral overlapping of 1.83 µm band of Tm³⁺ ions and 2.0 µm band of Ho³⁺ ions. Further, about 103% enhancement was acquired after the introduction of 0.1 mol% CeO₂ and 7.5 mol% WO₃ at the same time, which is primarily caused by the cross-relaxation between Tm³⁺ and Ce³⁺ ions together with the enhanced energy transfer from the Tm³⁺:³F₄ level to Ho³⁺:⁵I₇ level due to the increase in phonon energy. Spectral characteristics associated with the radiative transition of Ho³⁺ and Tm³⁺ ions on the basis of Judd-Ofelt theory, and the fluorescence decay behaviors after the addition of Ce³⁺ ions and WO₃ component were analyzed to understand the broadband and luminescence enhancement. The findings in this work indicate that tellurite glass with optimal Tm³⁺-Ho³⁺-Ce³⁺ tri-doping combination and appropriate amount of WO₃ is a prospective candidate for broadband optoelectronic devices operated in the infrared bands.

Optical thermometry of Er3+ in electrospun yttrium titanate nanobelts

Er³⁺/Yb³⁺ co-doped Y₂Ti₂O₇ (YTOEY) nanobelts with a thickness of ∼100 nm exhibiting a high sensitivity and rapid responsiveness in temperature sensing are obtained.

Synthesis of strong red emitting Y2O3:Eu3+ phosphor by potential chemical routes: comparative investigations on the structural evolutions, photometric properties and Judd–Ofelt analysis

A comparative investigation on the structural and photoluminescence properties of Y₂O₃:Eu³⁺ phosphor prepared by different routes such as sol-lyophilisation, combustion, hydrothermal and microwave assisted hydrothermal combustion, has been reported for the first time.