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Rare earth-doped phosphor materials have always remained in focus for excellent luminescence properties. Herein we have synthesized Yb3+ and Er3+-doped BaWO4 nanophosphor via facile hydrothermal method with red and green region emissions by 980 nm excitation. Red and green region emissions were observed due to 4F9/2 → 4I15/2 and 2H11/2/4S3/2 → 4I15/2 transitions, respectively, of Er3+, where Yb3+ acts as a sensitizer. The sample characterization was done using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS) techniques. The consequences of different concentrations of activator ion (Er3+) in BaWO4: Yb3+, Er3+ were studied from luminescence perspective in detail. The intensity of overall emission varied with altering the power of excitation that influences the photon transfer pathways. It was found that two-photon processes control both red and green emissions in the upconversion process. Decay behavior for both the emission was investigated. Thus, the tunable photoluminescence property suggests its potential in optoelectronic applications. [ABSTRACT FROM AUTHOR]

In recent years, rare-earth doped phosphors have gathered immense attention in the luminescence field for lighting and electronic display applications. However, the unavailability of an efficient and low-cost red phosphor is a major challenge for the widespread deployment of white light-emitting diodes (WLEDs) for practical purposes. Here we report red light-emitting Li+ co-doped ZnAl2O4:Eu3+ nanophosphors synthesized by a modified sol–gel route. These nanophosphors show excellent red emission due to the 5D0 → 7Fj (j = 1, 2, 3, and 4) transition of Eu3+ ions under 394 nm excitation. Li+ co-doped ZnAl2O4:Eu3+ nanophosphors exhibit an almost 2-fold increase in photoluminescence (PL) intensity upon incorporation of the optimum amount of Li+ in the ZnAl2O4:Eu3+ matrix. Apart from that, Li+ co-doping leads to the improvement of CIE coordinates that is also reflected from the enhanced color purity offered by the co-doped nanophosphors. Steady-state as well as time-resolved PL spectra clearly reveal that addition of Li+ co-activator successfully reduces nonradiative transitions in the co-doped nanophosphors. Introduction of Li+ in Eu3+ doped ZnAl2O4 effectively neutralizes the charge imbalance problem and thus leads to a significant increase in the PL efficiency of the nanophosphors. The red LED fabricated by those co-doped nanophosphors exhibits strong red emission under a driving voltage of 3 V. Obtained results strongly highlight the bright prospect of Li+ co-doped ZnAl2O4:Eu3+ nanophosphors in the LED and display applications. [ABSTRACT FROM AUTHOR]

Generation of white light requires a proficient strategy for appropriate mixing of red, green and blue emissions in appropriate proportion through optimization of material composition. However, it is quite challenging to develop a single host material showing emission in full visible region, which can be excited by a single excitation source. Herein, a series of Yb3+-sensitized Ho3+/Tm3+ co-doped BaWO4 nanophosphors synthesized by hydrothermal method is reported. The effect of different concentration of sensitizer ion (Yb3+) on the luminescence properties of BaWO4:Yb3+/Ho3+/Tm3+ crystal is investigated in detail to obtain white light. The phosphors exhibited red, green and blue luminescence centered at 651 nm, 539 nm and 482 nm respectively under a 980 nm excitation. The obtained novel nanophosphor could be a major potential candidate for nanobiotechnology and optoelectronics device applications. [ABSTRACT FROM AUTHOR]