Al2O3:xCr2O3고용상의 발광특성과 적색형광체의 연색성 향상을 위한 첨가제로의 응용

Abstract

In this article photoluminescence of the Al₂O₃:xCr₂O₃ solid solutions prepared by solid state reaction method are represented. The effect of Cr₂O₃-activator concentration and heat treatment time on the PL characteristics have been discussed in conjunction with microstructure of phosphor samples. The Al₂O₃:xCr₂O₃ phosphors show the highest PL intensity at x=0.003 mole when the samples are reacted at 1600℃ for 5 h. The PL emission and absorption spectra show the maximum peaks at 698 ㎚ and at 398 ㎚ respectively. The CIE color coordinate is (x=0.646, y=0.316) at 0.003 mole Cr₂O₃, which value is very close to the NTSC coordinate of red color. This characteristic feature of Al₂O₃:xCr₂O₃ has been applied for an additive to improve the color characteristic of other red phosphor LiEuW₂O? which has a relatively poor color purity with an emission peak centered at 615 ㎚ and with a CIE coordinate (x=0.530, y=0.280). The Al2O3:0.003Cr₂O₃ phosphor has been mixed with the LiEuW₂O? phosphor powder and the PL characteristics and CIE color coordinates are characterized. The Al₂O₃:xCr₂O₃ phosphor was found effective for improving the CRI (color rendering index) of LiEuW₂O? phosphor.