1,720,976 research outputs found
Enhancing the upconversion luminescence properties of Er 3+ –Yb 3+ doped yttrium molybdate through Mg 2+ incorporation: effect of laser excitation power on temperature sensing and heat generation
No full textSynthesis and Upconversion Emission Properties of Green Emitting Y<SUB>4</SUB>MoO<SUB>9</SUB>: Er<SUP>3</SUP><SUP>+</SUP>/Yb<SUP>3</SUP><SUP>+</SUP> Phosphor
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Up/down-converted green luminescence of Er3+-Yb3+ doped paramagnetic gadolinium molybdate: a highly sensitive thermographic phosphor for multifunctional applications
No full textA series of Er3+-Yb3+ doped gadolinium molybdate phosphors were synthesized via hydrothermal method with varying Er3+ and Yb3+ concentrations and their thermal stability, crystal phase formation, particle morphology and photoluminescence properties were explored. The effects of rare earth doping concentration and annealing temperature on upconversion and downconversion properties have been investigated upon 980 nm and 380 nm light excitation and explained with the variation in lifetime of the S-4(3/2) level of Er3+. The materials were further investigated to look into the effect of Er3+-concentration on optical temperature sensing and nano-heating behavior. Temperature sensing measurements were performed by the fluorescence intensity ratio technique using the transitions from the two thermally coupled energy levels (H-2(11/2)/S-4(3/2) -> I-4(15/2)) of Er3+. The maximum temperature sensitivity was obtained as 0.0105 K-1 (at 450 K), which is among the highest measured sensitivities for luminescence based thermometers. Moreover, the material shows very high thermal gain due to laser irradiation, resulting in a temperature rise from 364 K to 683 K as the excitation power changes from 7.0 to 65 W cm(-2) and defines the present material as a highly sensitive thermographic phosphor. Additionally, the paramagnetic nature and effect of the magnetic field on upconversion properties of this phosphor have also been explored. The thermally-stable, paramagnetic Gd2Mo3O9:Er3+/Yb3+ phosphor particles seem to be potential candidates for displays, remote temperature sensing, optical heaters, magneto-optic modulators and bio-imaging applications
Photoluminescence properties of europium-activated double layered perovskite Sr 3 Ti 2 O 7 for high-quality lighting applications
No full textThermally stable double-layered perovskite materials for solid-state lighting applications.We present a comprehensive investigation into the concentration and temperature-dependent photoluminescence (PL) properties of europium ion (Eu 3+ ) activated double-layered perovskite Sr 3 Ti 2 O 7 materials. We conducted thorough analyses to assess their phase purity, crystal structure, surface morphology, and optical properties to gain a complete understanding. The double-layered perovskite Sr 3 Ti 2 O 7 :Eu 3+ exhibited a tetragonal phase with space group I 4/ mmm . When excited by 395 nm ultraviolet (UV) light, the prepared materials exhibited a firm red emission peak at 616 nm, indicating the hypersensitive electric dipole transition 5 D 0 → 7 F 2 in Eu 3+ ions. The quantum yield of the optimized sample was estimated to be 18%. To explore the temperature-dependent behavior of the photoluminescence, measurements were carried out over a wide range of temperatures from 300 K to 450 K. Notably, the phosphors demonstrated significant thermal stability, with 75% of the emission intensity retained at 420 K compared to 300 K. These findings signify the material's ability to maintain its luminescent properties at elevated temperatures. The photometric characterization of Sr 3 Ti 2 O 7 :Eu 3+ further validated its red emission capability. Moreover, we employed the Judd–Ofelt approach to examine the radiative intensity parameters ( Ω 2 , Ω 4 , Ω 6 ). The obtained results provide substantial support for the promising prospects of this perovskite material in the rapidly growing field of solid-state lighting and display devices.Thermally stable double-layered perovskite materials for solid-state lighting applications.We present a comprehensive investigation into the concentration and temperature-dependent photoluminescence (PL) properties of europium ion (Eu 3+ ) activated double-layered perovskite Sr 3 Ti 2 O 7 materials. We conducted thorough analyses to assess their phase purity, crystal structure, surface morphology, and optical properties to gain a complete understanding. The double-layered perovskite Sr 3 Ti 2 O 7 :Eu 3+ exhibited a tetragonal phase with space group I 4/ mmm . When excited by 395 nm ultraviolet (UV) light, the prepared materials exhibited a firm red emission peak at 616 nm, indicating the hypersensitive electric dipole transition 5 D 0 → 7 F 2 in Eu 3+ ions. The quantum yield of the optimized sample was estimated to be 18%. To explore the temperature-dependent behavior of the photoluminescence, measurements were carried out over a wide range of temperatures from 300 K to 450 K. Notably, the phosphors demonstrated significant thermal stability, with 75% of the emission intensity retained at 420 K compared to 300 K. These findings signify the material's ability to maintain its luminescent properties at elevated temperatures. The photometric characterization of Sr 3 Ti 2 O 7 :Eu 3+ further validated its red emission capability. Moreover, we employed the Judd–Ofelt approach to examine the radiative intensity parameters ( Ω 2 , Ω 4 , Ω 6 ). The obtained results provide substantial support for the promising prospects of this perovskite material in the rapidly growing field of solid-state lighting and display devices.Alexander von Humboldt-Stiftung https://doi.org/10.13039/10000515
Yb3+ sensitized Na2Y2B2O7:Er3+ phosphors in enhanced frequency upconversion,.temperature sensing and field emission display
No full textNa2Y2B2O7:Er3+/Yb3+ crystalline phosphors with single monoclinic phase have been synthesized by urea assisted solution combustion method and characterized through X-ray diffraction and Field emission scanning electron microscopy analysis. Frequency upconversion (UC) emission study has been carried out upon 980 nm laser diode excitation and maximum enhancement of about similar to 1433 times for the UC emission intensity of the green band in the codoped phosphor compared to that of the singly Er3+ doped phosphor has been reported. Optical temperature sensing study performed in the developed codoped phosphor reveals that the material can be used temperature sensing application within 300-613K temperature range with maximum sensitivity similar to 7.9 x 10(-3)K(-1) at 300 K. The low-voltage cathodoluminescence measurements have been performed for Na2Y2B2O7:Er3+-Yb3+ phosphors as a function of accelerating voltage and filament current. The developed phosphors exhibit highly intense green emission with some weak emission bands in violet, blue and red regions upon electron beam excitation. (C) 2017 Elsevier Ltd. All rights reserved
Er3+-Yb3+ doped vanadate nanocrystals: A highly sensitive thermographic phosphor and its optical nanoheater behavior
No full textOptical temperature sensors play a vital role in biomedical and therapeutic applications due to their reliable and unique detection sensitivity. Internal self-heating in Er3+/Yb3+ doped yttrium vanadate particles is observed on optical excitation at 980 nm wavelength of a diode laser. Temperature sensing performance is investigated by exploiting the temperature dependent fluorescence intensity ratio (FIR) of two emission bands (H-2(11/2)/S-4(3/2)-> I-4(15/2)) of Er3+ ion. The calculated sensor sensitivity, 0.01169 K-1 at 380 K, is found the highest among the reported results for inorganic nanosensors. The temperature of the nanocrystalline sample particles is found to increase by a large value (315-460 K) within a short interval of excitation pump power (13.18-50.45W cm(-2)). This achievement suggests potential use of the present material as an optical nanoheater for hyper-thermal treatment. (C) 2014 Elsevier B.V. All rights reserved
Comparative thermometric properties of bi-functional Er<sup>3+</sup>–Yb<sup>3+</sup> doped rare earth (RE = Y, Gd and La) molybdates
No full textPhotoluminescence and cathodoluminescence studies of Er<sup>3+</sup>-activated strontium molybdate for solid-state lighting and display applications
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