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Upconversion luminescence properties of Y2O3: Yb3+/Er3+/Tm3+ nanocrystal doped PMMA nanocomposites
摘要： Y2O3 nanocrystals triply doped with Yb3+, Er3+, Tm3+ ions were synthesized via alginic acid-assisted gelation using thermal decomposition method and annealed at 800 °C for 24 h. Nanopowders were embedded into PMMA matrix via free-radical polymerization in an ultrasonic bath. X-ray diffraction and transmission electron microscopy measurements have shown that the crystal grain sizes decreased significantly with the narrow size distributions of the nanocrystals in PMMA matrix. A diode laser at 975 nm was used to measure the upconversion luminescence of the annealed nanopowders and those embedded in PMMA between the 400–850 nm wavelength region. The Er3+ concentration and the excitation power density dependencies of the relative intensities for red, green and blue upconversion luminescence in the nanopowder and PMMA nanocomposites are found to be different. The measured CIE-1931 color coordinates of the upconversion luminescence in PMMA nanocomposites show appreciable color stability under different excitation power densities, which is required for potential applications in the field of photonics.
关键词： Color Tunable Emission,Upconversion Luminescence,Polymer nanocomposites,Color Stability,Polymethyl methacrylate (PMMA)
更新于2025-09-23 15:21:21
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Color tunable upconversion luminescence and optical thermometry properties of mixed Gd2O3:Yb3+/Ho3+/Er3+ nanoparticles prepared via laser ablation in liquid
摘要： The mixtures of Gd2O3:Yb3+/Er3+ and Gd2O3:Yb3+/Ho3+ nanoparticles were successfully prepared via pulsed laser ablation in liquid followed by solution mixing. Under excitation of 980 nm diode laser, tunable color from green to red emission was achieved. Based on the thermal linked energy levels, the temperature sensitive upconversion emission was observed. The fluorescence intensity ratio (FIR) of I513–530 nm/I530–580 nm increased as the elevation of temperature. The absolute sensitivity and relative sensitivity were derived from temperature dependent FIR. The results show that the mixture of Gd2O3:Yb3+/Er3+ and Gd2O3:Yb3+/Ho3+ nanoparticles are not only potential candidates for multicolor upconversion luminescence but also promising optical materials for non-contact optical thermometry.
关键词： Gd2O3 nanoparticles,Color tunable emission,Pulsed laser ablation in liquid,Optical thermometry,Upconversion luminescence
更新于2025-09-23 15:21:01
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The synthesis and luminescent properties of Dy/Re (Re?=?Tb or Eu) co-doped Gd2(WO4)3 phosphor with tunable color via energy transfer
摘要： The new systems of the (Gd0.95-xDy0.05Tbx)2(WO4)3 (x = 0–0.1) and (Gd0.95-yDy0.05Euy)2(WO4)3 (y = 0–0.2) phosphors have been successfully obtained using the hydrothermal method at 900 °C in this work. The crystal structure, morphology, PL/PLE spectra, ?uorescence and decay analysis have been studied in detail via the combined techniques of XRD, FE-SEM, PLE/PL spectra and decay kinetic. The phase-pure of the (Gd0.95-xDy0.05Tbx)2(WO4)3 and (Gd0.95-yDy0.05Euy)2(WO4)3 with good dispersions have been formed at the lower sintering temperature of 900 °C. Under 273 nm and 270 nm excitation (the 6P7/2→8S7/2 transitions of Gd3+), the Gd2(WO4)3:Dy3+/Tb3+ and Gd2(WO4)3:Dy3+/Eu3+ phosphors exhibit both Dy3+ (yellow, at 574 nm) and Tb3+ (green, at 547 nm) as well as Dy3+ (yellow, at 574 nm) and Eu3+ (red, at 616 nm) emissions, respectively. The presences of WO4 2-, Gd3+ and Dy3+ excitation bands on the PLE spectra by monitoring the Tb3+ and Eu3+ emissions directly provide an evidence of energy transfer of WO4 2-→Tb3+, Gd3+→Tb3+ and Dy3+→Tb3+, as well as WO4 2-→Eu3+, Gd3+→Eu3+ and Dy3+→Eu3+, respectively. The quenching concentrations of both two systems are determined to be 7 at% (x = 0.07 for Tb3+) and 10 at% (y = 0.10 for Eu3+), and the quenching mechanisms of both two systems are mainly due to the Tb3+-Tb3+ and Eu3+-Eu3+ energy transfers, respectively. The color-tunable emission can be achieved though adjusting the relative content ratios of Dy3+/Tb3+ or Dy3+/Eu3+, which has been veri?ed by the CIE chromaticity coordinates analysis. The energy transfer e?ciencies of Dy3+→Tb3+ and Dy3+→Eu3+ have been calculated, and the energy transfer mechanisms have been analyzed in detail. The (Gd0.95-xDy0.05Tbx)2(WO4)3 and (Gd0.95-yDy0.05Euy)2(WO4)3 phosphors with color-tunable emission may have a potential application for w-LEDs.
关键词： Color-tunable emission,Gd2(WO4)3:Dy3+/Tb3+,Gd2(WO4)3:Dy3+/Eu3+,Luminescent property
更新于2025-09-10 09:29:36