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The article explores the photoluminescence properties of UV, near-UV and blue excited BaWO 4 : Eu3+ red phosphors. The optical band gap narrowing is observed after adding Eu3+ ions. The excitation spectra exhibit a broad peak centred at 255 nm and several narrow peaks of Eu3+ ions at 362, 382, 395, 415 and 465 nm. The three peaks located at 255 (UV), 395 (near-UV) and 465 nm (blue) are the most intense and suitable for the excitation of the sample. The spectral profile of the emission spectra irradiated at 255, 395 and 465 nm are identical. The brightest emission is realized at 18 mol% doping of Eu3+ ions at 255 and 465 nm excitations. However, the optimum concentration is 16 mol% at 395 nm excitation. The phosphors emit highly pure red lights with color purity 98.192%, 97.794% and 98.693% for the optimised concentration under UV, near-UV and blue excitations of 255, 395 and 465 nm, respectively. The quantum efficiency of BaWO 4 : 16 mol% Eu3+ phosphor is calculated as∼48.234% at 395 nm excitation. The emission intensity parameters are calculated in view of the Judd-Ofelt theory. The spectroscopic parameters like radiative transition probability, radiative lifetime, branching ratio and stimulated emission cross-section are further evaluated from the three emission spectra recorded at 255, 395 and 465 nm excitations. The derived results advocate the use of synthesized material as a red phosphor in white-LED, laser and display devices. [ABSTRACT FROM AUTHOR]

A series of white light emitting Pr3+ activated SrWO 4 phosphors are synthesized by most facile solid state reaction routes. The structural properties are investigated by X-ray diffraction (XRD) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Energy dispersive X-ray (EDX) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray photoemission spectroscopy (XPS). The optical properties are elaborated in detail using UV–visible–NIR spectroscopy and Photoluminescence (PL) spectroscopy. Rietveld refinement of obtained XRD data is performed to investigate the crystal structure and crystallographic parameters. The photoluminescence measurements ensure that the developed phosphors emit bright white light under UV excitation of 242 nm and blue excitation of 448 nm. The maximum emission intensity is achieved at 3 mol% doping of Pr3+, followed by concentration quenching due to dipole-dipole interactions. The decay of electrons from the most populated 3P 0 state in all the samples follows the single exponential nature. The average decay time varies in the same manner as the emission intensity with Pr3+ concentration. The color purities of the lights emitted from all the materials under 242 nm and 448 nm excitations are low (close to 10%) and hence suitable for white light. A bright white LED is successfully fabricated by coating the optimised phosphor SrWO 4 : 3 mol% Pr3+ on a 460 nm blue LED chip. The interesting results recommend that the proposed material can be used in developing single phase white-LED. [ABSTRACT FROM AUTHOR]