Cation sites modification enhanced luminescence and thermal quenching characteristic in the blue light-emitting Na3Sc2-xZnx(PO4)3:0.03Eu2+ phosphors

Eu2+ luminescence in the host of Na3Sc2(PO4)3 have attracted increasing attention due to its zero-thermal quenching phenomenon. In this paper, we have investigated a site modification strategy, in which Zn2+ is substituted for partial Sc3+ of the host lattice, and find such a strategy benefits great deal to Eu2+ luminescence. Through the solid-state reaction, a series of modified Na3Sc2-xZnx(PO4)3:0.03Eu2+ phosphors was synthesized. Phase purity of the synthesized phosphors was identified by powder X-ray diffraction and their luminescence properties were studied through excitation and emission spectra, fluorescence lifetime, quantum efficiency, temperature-dependent emission spectra and thermoluminescence spectra. With the nonequivalent substitution, the modified Na3Sc2-xZnx(PO4)3:0.03Eu2+ phosphors exhibit higher luminescence intensity. In the meantime, thermal performance of Eu2+ photoluminescence has been further optimized. Finally, the white light-emitting diodes (WLEDs) application is examined by combining 340 nm near ultraviolet (n-UV) LED chip and phosphors (Blue: Na3Sc1.92Zn0.08(PO4)3: 0.03Eu2+, Yellow: Y3Al5O12: Ce3+, Red: K2SiF6: Mn4+). The fabricated WLED device has excellent properties with CIE color coordinate x = 0.3844, y = 0.4206, correlated color temperature (CCT) = 4161 K and color rendering index (Ra) = 93.8, indicating the potential application in WLED fields.