Synthesis and luminescence characteristics of finesized Ba3Si6O12N2:Eu green phosphor through spray pyrolysis using TEOS/Si3N4 mixed precursors

摘要

Fine-sized Ba3Si6O12N2: Eu2+ phosphor powders were synthesized by spray pyrolysis using tetraethyl orthosilicate (TEOS) and Si3N4 nanopowder as Si precursors, and the crystallographic and luminescence characteristics were explored with changing the mole ratio of TEOS to Si3N4. When only Si3N4 was used as the Si precursor, the main phase of the resulting particles was Ba3Si6O9N4 and the Ba3Si6O12N2 phase was formed as an impurity phase. As the TEOS mole fraction increased as the Si precursor, the main phase changed from Ba3Si6O9N4 to Ba3Si6O12N2, and BaSi2O5 was formed as the main phase when the TEOS fraction was 80% or higher. As a result, the excitation and emission intensity were largely affected by changing the TEOS/Si3N4 ratio. Finally, the optimal TEOS/Si3N4 mole ratio was determined as 50/50 in terms of preparing Ba3Si6O12N2: Eu particles having the highest emission through spray pyrolysis. At the TEOS fraction of 50%, the crystallographic form and the emission properties were investigated as the calcination temperature was varied from 700 degrees C to 1350 degrees C. It was found that Ba2Si3O8 is generated as an intermediate phase at a calcination temperature of lower than 1200 degrees C and a pure Ba3Si6O12N2 phase without any impurity phases was obtained at 1300 degrees C. Based on XRD analysis, a possible formation mechanism of Ba3Si6O12N2: Eu was discussed. The prepared Ba3Si6O12N2: Eu2+ powder exhibited high thermal stability with the thermal activation energy of 0.247 eV and a fine size of less than 1 mm without significant agglomeration.