Abstract
In this paper, the effect of the GeO(2):TiO(2) molar ratio in glass composition on the spectroscopic properties of germanate glasses was systematically investigated. The visible luminescence bands associated with characteristic (1)D(2) → (3)H(4) (red), (5)S(2), (5)F(4) → (5)I(8) (green), and (1)D(2) → (3)F(4) (blue) transitions of Pr(3+), Ho(3+), and Tm(3+) ions in systems modified by TiO(2) were well observed, respectively. It was found that the luminescence intensity of glasses containing Pr(3+) and Ho(3+) ions increases, whereas, for Tm(3+)-doped systems, luminescence quenching with increasing content of TiO(2) was observed. Based on Commission Internationale de I'Eclairage (CIE) chromaticity coordinates (x, y) analysis, it was demonstrated that the value of chromaticity coordinates for all glasses depends on the GeO(2):TiO(2) molar ratio. The addition of TiO(2) to system compositions doped with Tm(3+) ions shifts the (x, y) to the center of the CIE diagram. However, chromaticity coordinates evaluated for glasses containing Pr(3+) ions move to a purer red color. Our results confirm that the spectroscopic properties of the studied glasses strongly depend on TiO(2) content. Moreover, it can be stated that germanate-based glass systems modified by TiO(2) can be used for optoelectronics in RGB technology as red (Pr(3+)), green (Ho(3+)), and blue (Tm(3+)) emitters.