Highly efficient visible-light-assisted photocatalytic reduction of Cr(VI) to Cr(III) from water using multifunctional Zr(IV)-porphyrin MOFs, Zr6(μ3-OH)8(OH)8(MTCPP)2, (PCN-222(M)) (M = H2, ZnII, CuII, NiII, CoII, FeIIICl, and MnIIICl) is presented. The...

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 → 7F j (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.

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