Deep red-emitting Ca14Al10Zn6O35 Mn4+ phosphors for WLED applications

Novel deep red-emitting Ca14Al10Zn6O35:Mn4+ (CAZ:Mn4+) phosphors were synthesized by a citrate sol-gel method. The X-ray diffraction patterns of CAZ:Mn4+ phosphors confirmed their cubic structure after annealing at 1200 degrees C. The photoluminescence emission (PL) and excitation (PLE) spectra were measured to examine the emission richness of CAZ:Mn4+ phosphors. The PLE spectra of CAZ:Mn4+ phosphor exhibited a broad band, between UV and blue regions, due to the charge transfer (CT) transition of Mn4+-O2- and (4)A(2g)-> T-4(2g), (4)A(2g)-> T-4(2g), (4)A(2g)-> T-4(2g) of Mn4+ ions. The results showed that the deep red emission peak of the CAZ:Mn4+ phosphor was located at 714 nm due to the E-2(g)->(4)A(2g) transition of Mn4+ ion, which was effectively excited by 450 nm. The optimum concentration of Mn4+ ion in Ca14Al10Zn6O35 host lattice was found to be at 3 mol%. Using CAZ:3Mn(4+) phosphors, white light-emitting diode (WLED) was fabricated. The CIE chromaticity coordinates of CAZ:3Mn(4+) and fabricated WLED located at (0.709, 0.291) and (0.338, 0.396), respectively, resulting in the generation of warm white light for indoor illumination. (C) 2017 Elsevier B.V. All rights reserved.