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Gamma ray enhanced Vis-NIR photoluminescence and cytotoxicity of biocompatible silica coated Nd3+ doped GdPO4 nanophosphors
摘要： Near infrared (NIR) emitting nanophosphors have a great potential for biomedical applications. Core nanoparticles of Nd3+ doped GdPO4@SiO2 with 3–6 nm sized spheres have been synthesized by solution combustion synthesis. The structure, morphology and luminescence properties of as synthesized nanophosphors have been examined by X-ray diffraction, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Photoluminescence spectra (PL). Upon photoexcitation at 532 nm, GdPO4:Nd3+@SiO2 emits red luminescence at 681 nm and NIR luminescence at 797 nm corresponding to 4F9/2 → 4I9/2 and 4F5/2 → 4I9/2 transitions, respectively. The luminescence intensity of nanophosphor had enhanced 2 folds on increasing the Nd3+ content from 1% to 5%. The luminescence intensity of these nanophosphors had further enhanced 2–3 folds and 8–10 folds after exposed to 150 kGy and 300 kGy of gamma radiation, respectively. In addition, this nanophosphor also exhibits high cytotoxicity against cell lines of PC-3 (Prostate cancer cells) and MCF-7 (Breast cancer cells).
关键词： Cytotoxicity,Gamma radiation,SiO2,Photoluminescence,Nanophosphors
更新于2025-09-10 09:29:36
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Photoluminescent and structural properties of color tunable trivalent europium doped SrGdAlO4 nanophosphors
摘要： A series of Eu3+ ion doped SrGdAlO4 nanophosphors were prepared via solution combustion technique utilizing urea as a fuel. Structural properties of the tetragonal phase of the host/doped lattice belonging to the space group I4/mmm were characterized by powder X-ray diffraction (PXRD). Photoluminescence spectra, decay curves, UV–Visible diffuse reflectance spectra (UV–Vis DRS) and Judd–Ofelt analysis were utilized to characterize the photoluminescent properties. The radiative rates (Ar), branching ratios (Br) and intensity parameters (?λ) were estimated by Judd–Ofelt analysis. The optimal doping concentration of europium ions for SrGdAlO4 host lattice was found to be 20 mol%, above which concentration quenching was observed due to dipole–dipole interactions. CIE coordinates values lie in the blue region at lower concentrations of Eu3+ ions, which shifted towards white and then to reddish-orange region with higher concentrations of Eu3+ ions, suggesting the color tunable property of the synthesized nanophosphors. Lower value of CCT and color tunable phenomenon proved it as potential candidate for warm white light and phosphor converted white light emitting diodes (Pc-WLEDs) applications. The optical band gap of both host lattice (5.50 eV) as well as of 20 mol% Eu3+ doped SrGdAlO4 nanophosphors (5.26 eV) lie in the range of semiconductors which enhanced their areas of applications.
关键词： Nanophosphors,Color tunability,Solution combustion,Photoluminescence,Judd–Ofelt analysis,Semiconductor
更新于2025-09-09 09:28:46
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Structural and luminescence properties of Eu3+ doped LaAlO3 nanophosphors by hydrothermal method
摘要： A series of La1?xAlO3: xEu3+ (x = 0, 2, 4, 6 and 8 mol%) nanophosphors have been synthesized by a hydrothermal technique and were investigated by an X-ray powder diffractometer, field emission scanning electron microscopy, high-resolution transmission electron microscopy and fourier transform infrared spectroscopy. Further, photoluminescent studies have also been orderly explored under the near-ultraviolet light excitation. When excited with 395 nm, the Eu3+: LaAlO3 nanophosphors emission peaks observed at 579, 591, 620, 649 and 700 nm due to the 5D0→7Fj (J = 0–4) transitions of Eu3+ ions. The prominent emission peak was perceived at 620 nm, which associated to the 5D0→7F2 hypersensitive transition of Eu3+ ion. The optimum doping concentration of Eu3+ in LaAlO3 host is around 6 mol% and the concentration quenching effect is through the dipole–dipole interaction. The Commission International de I’Eclairage (CIE) color co-ordinates were determined from emission spectra and the values (x, y) were closer to National Television Standard Committee typical value of red emission. As an outcome, the prepared nanophosphors are highly suitable for red component of white light emitting devices.
关键词： white LEDs,nanophosphors,hydrothermal method,photoluminescence,LaAlO3:Eu3+
更新于2025-09-04 15:30:14