Non-Rare Earth and Fluoride-Free Red Emitting Phosphor: A combined Experimental and Ab Initio Study

Abstract

Red light phosphor is the key component for stimulating natural sunlight LEDs Recent years Mn4+ luminescence centers are commonly used to substitute environmentally hazardous rare-earth dopants However the choice of matrix materials is usually fluoride compound e g K2TiF6 which derivate contaminate issues on silicon industry In this paper the ecofriendly “rare-earth-free” and “flouoride-free” red light luminance material Mg2TiO4 (MTO) with the luminescent center of Mn4+ (MTO:Mn) is investigated The atomistic models were constructed using ab initio calculations based on density functional theory The density of states of MTO:Mn with varies potential sensitizers reveal that the best candidate for sensitizer is niobium (Nb) In addition phosphors were fabricated via solid state sintering X-ray diffraction spectrum shows no meta-stable phase and photoluminescence spectrum indicates the intensity of light is around 243% after sensitization This report successfully proposes a novel method to understand optoelectronic properties of phosphors and in turn obtain desirable products In addition Mg2TiO4 thin films were as well discussed here Fabricated by either sol-gel or radio frequency sputtering annealed at various temperatures and characterized using photoluminescence spectroscopy Essential physical and optoelectronic properties of the Mg2TiO4 luminance material as well as its optimal processing conditions were comprehensively reported

Date of Award	2016 Jul 7
Original language	English
Supervisor	Cheng-Liang Huang (Supervisor)