The Preparation And Study On Influencing Factors Of Mg₂Sr_2-xTiO₄: Eu³⁺, Gd³⁺ Red Luminescent Materials

As the fourth solid generation light source in the21st century, white LEDhas received wide attention and has broad application prospects with its uniqueadvantages. The preparation and research of quality inorganic fluorescentmaterial have important implications for improving WLED colors, fluorescentbrightness, white uniformity, and color temperature. With the two major themesof green lighting: energy saving and environmental protection has been proposed,the development of white LED is more rapid, and the performance of the redphosphor directly affects the white LED color rendering index.In this thesis, the gel precursor of titanate red phosphor doped with rareearth ions was synthesized by sol-gel method, then luminous powder wasobtained by calcining the pretreated precursor at high temperature. The Phasecomposition and microstructure were studied by X-ray diffraction and SEM. Theinfluence factors on the luminescent properties of materials have been analyzedsuch as the doping amount of Eu³⁺, the calcination temperature and calcinationtime of xerogel precursor, the doping amount of alkaline earth metal ions (Ca²⁺,Sr²⁺), the doping amount of Gd³⁺, charge compensation （Li, Na, K）, complexingagents citric acid and pH. The colorimetric parameters such as color purity andcolor temperature by CIE color coordinates have been researched.It can be obtained from the test results:（1） the excitation peaks of preparedphosphor are at395nm and465nm, and the main emission peaks are at591nm,614nm,657nm, which can match with blue and near-ultraviolet LED chip.（2）The optimum conditions of preparation can be obtained: the optimum dopingconcentration of Eu³⁺and Sr²⁺is2mol%and5mol%respectively, the optimumcalcination temperature is1150℃, the optimum calcination time is5h, the optimal molar ratio of activators and sensitizers is Eu³⁺: Gd³⁺=1:1, the optimumdoping concentration of charge compensation Na+is1.5mol%, molar ratio ofcomplexing agent citric acid and the metal ions is1.5:1, the optimum pH is3.（3）The chromaticity coordinates of luminescent material are X=0.654, Y=0.342. Asthe color coordinates displayed as red-orange light, the hue is red. The saturationis better. And the color temperature is267805K. It can meet the needs of redlight-emitting materials to WLED.