Crystal structure and Temperature-Dependent Luminescence Characteristics of KMg4(PO4)3:Eu2+ phosphor for White Light-emitting diodes

Abstract

The KMg4(PO4)3:Eu2+ phosphor was prepared by the conventional high temperature solid-state reaction. The crystal structure, luminescence and reflectance spectra, thermal stability, quantum efficiency and the application for N-UV LED were studied respectively. The phase formation and crystal structure of KMg4(PO4)3:Eu2+ were confirmed from the powder X-ray diffraction and the Rietveld refinement. The concentration quenching of Eu2+ in the KMg4(PO4)3 host was determined to be 1mol% and the quenching mechanism was certified to be the dipole–dipole interaction. The energy transfer critical distance of as-prepared phosphor was calculated to be about 35.84Å. Furthermore, the phosphor exhibited good thermal stability and the corresponding activation energy ΔE was reckoned to be 0.24eV. Upon excitation at 365nm, the internal quantum efficiency of the optimized KMg4(PO4)3:Eu2+ was estimated to be 50.44%. The white N-UV LEDs was fabricated via KMg4(PO4)3:Eu2+, green-emitting (Ba,Sr)2SiO4:Eu2+, and red-emitting CaAlSiN3:Eu2+ phosphors with a near-UV chip. The excellent color rendering index (Ra = 96) at a correlated color temperature (5227.08K) with CIE coordinates of x = 0.34, y = 0.35 of the WLED device indicates that KMg4(PO4)3:Eu2+ is a promising blue-emitting phosphor for white N-UV light emitting diodes (LEDs).

Red-light-emitting inorganic La2CaZnO5 frameworks with high photoluminescence quantum efficiency: Theoretical approach

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Judd-Ofelt and structural analysis of colour tunable BaY 2 ZnO 5 :Eu 3+ nanocrystals for single-phased white LEDs

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“…A lot of efforts are being put into the fabrication of light-emitting diodes owing to their potential candidature in white light generation for solid state lightning devices. White LEDs are very much advantageous in a number of aspects like the less power consumption, higher durability, a longer life time, mercury-free and less pollution over the conventional incandescent and halogen lamp [1]. One of the Conventional method for the fabrication of white light-emitting diodes (WLEDs) is to coat a blue GaN LED chip (λ ex = 450-470 nm) with a yellow phosphor.…”

Synthesis, structure analysis and magnetic properties of Ca2TiMnO6 oxides

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