TY  - JOUR
AU  - YU, Huimei
AU  - JIANG, Mingda
AU  - ZHANG, Minghui
AU  - DONG, Xu
AU  - TENG, Xin
PY  - 2026
TI  - Er3+/Yb3+ co-doped La2O3–TiO2–Gd2O3 glasses with upconversion luminescence properties prepared by aerodynamic container-less levitation
JO  - Experimental Technology and Management
SN  - 1002-4956
SP  - 95
EP  - 100
VL  - 43
IS  - 4
AB  - ObjectiveContainer-less levitation technology, originally developed for simulating microgravity conditions in space, has become a crucial method for preparing advanced materials free from contamination and heterogeneous nucleation caused by containers. This technique is particularly valuable for synthesizing heavy-metal oxide glasses, which are challenging to produce using conventional melting methods due to their poor glass-forming ability and the need for rapid cooling. This study used aerodynamic levitation to fabricate novel Er3+/Yb3+ co-doped La2O3–TiO2–Gd2O3 (LTG) glasses and systematically investigated how different Gd2O3 concentrations affected the thermal stability and upconversion luminescence properties of the glasses. The goal was to develop high-performance upconversion materials for potential applications in solid-state lasers, optical temperature sensors, and biological labeling systems.MethodsGlasses with the nominal composition (La0.78−xGdxEr0.04Yb0.18) Ti2.25O6 (where x = 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, or 0.35%) were prepared using an aerodynamic levitation furnace. High-purity oxide powders were thoroughly mixed, pressed into rods, and introduced into the levitator. The samples were levitated and melted using a CO2 laser in an oxygen atmosphere, followed by rapid cooling to form spherical glass beads with a diameter of ~3 mm. The amorphous nature of the obtained glasses was confirmed through X-ray diffraction (XRD). Thermal properties, including the glass transition temperature (Tg), onset crystallization temperature (Tc), and crystallization peak temperature (Tp), were determined through simultaneous thermal analysis (STA) at a heating rate of 10 K/min. Upconversion luminescence spectra were recorded under 980 nm laser excitation using a fluorescence spectrophotometer equipped with a photomultiplier tube.ResultsXRD patterns confirmed the amorphous structure of all prepared LTG samples. DTA results indicated that Tg, Tc, and Tp decreased with increasing Gd2O3 concentration. The thermal stability parameter (ΔT = Tc − Tg), which reflects the glass-forming ability, also decreased from 59.4 ℃ to 42.6 ℃ as Gd2O3 concentration increased from 0.10% to 0.35%, suggesting a reduction in the thermal stability and glass-forming tendency with increasing Gd2O3 concentration. Under 980 nm laser excitation, intense green and red upconversion emissions were observed. The emission bands centered at 535, 553, and 672 nm corresponded to the 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2 transitions of Er3+, respectively. The green emission (553 nm) was notably more intense than the red emission across all compositions. The integrated upconversion luminescence intensity initially increased with increasing Gd2O3 concentration and peaked at x = 0.15% before decreasing. Furthermore, the ratio of green-to-red emission intensity exhibited a nonmonotonic trend: it first increased and then decreased, indicating that high Gd2O3 concentrations favored red emissions over green emissions. The upconversion mechanism involved ground-state absorption and energy transfer processes from Yb3+ to Er3+, followed by excited-state absorption, leading to the filling of high-energy levels and subsequent radiative transitions.ConclusionsThis study successfully demonstrated the effectiveness of aerodynamic levitation for fabricating Er3+/Yb3+ co-doped LTG heavy-metal oxide glasses, which are difficult to produce by conventional methods. Gd2O3 significantly affected both the thermal and luminescent properties of the glasses. Although increasing Gd2O3 concentration reduced thermal stability, it enabled the upconversion emission intensity and color ratio to be adjusted, with optimal luminescence performance achieved at a Gd2O3 concentration of x = 0.15%. The strong green emissions underscore the potential of these LTG glasses for various photonic applications. The combination of container-less processing and strategic compositional design provides a robust approach for developing new functional glass materials with tailored properties.
UR  - https://doi.org/10.16791/j.cnki.sjg.2026.04.010
DO  - 10.16791/j.cnki.sjg.2026.04.010