Luminescence and energy transfer in Dy 3+ /Tb 3+ co-doped transparent oxyfluorosilicate glass-ceramics for green emitting applications

Photoluminescence processes in τ -phase Ba 1.3 Ca 0.7- x - y SiO 4 : x D y 3+ / y Tb 3+ phosphors for solid-state lighting

“…As shown in figure 5 b , the emission spectra exhibit mainly nine emission bands due to the combined f ↔ f electronic transition of D y 3+ and Tb 3+ ions as expected from each single-doped phosphors in figure 4 a,b . Three emission bands are ascribed to D y 3+ ions of 4 F 9/2 → 6 H 15/2 (blue, 482 nm), 4 F 9/2 → 6 H 13/2 (yellow, 575 nm) and 4 F 9/2 → 6 H 11/2 (red, 707 nm) and the other six emission bands at 416, 438, 489, 545, 585 and 621 nm are corresponding to 5 D 3 → 7 F 5 , 5 D 3 → 7 F 4 , 5 D 4 → 7 F 6 , 5 D 4 → 7 F 5 , 5 D 4 → 7 F 4 and 5 D 4 → 7 F 3 transitions of Tb 3+ ions in the phosphor compounds, respectively [45,46]. In this work, the location of the assigned bands was calibrated by the emission wavelength of commercial InGaN UV-LED.…”

“…Accordingly, the excitation wavelength at 351 nm is appropriate for studying the photoluminescent process (e.g. white or green light emission) in Ba 1.3 Ca 0.7- x - y SiO 4 : x D y 3+ / y Tb 3+ ( x = 0.03 and y = 0.01–0.05) phosphors [44,46]. Furthermore, it was observed that after co-doping, the decay time of phosphors was extended (table 2).…”

“…Here, the elongated decay time for the co-doped phosphors in figure 7b suggests an additional relaxation pathway, leading to the nonexponential nature. For understanding the PL processes, the non-exponential decay curves were fitted according to Inkuti and Hirayama's model [44,46],…”

“…As shown in figure 5b, the emission spectra exhibit mainly nine emission bands due to the combined f ↔ f electronic transition of Dy 3+ and Tb 3+ ions as expected from each single-doped phosphors in figure 4a,b. Three emission bands are ascribed [45,46]. In this work, the location of the assigned bands was calibrated by the emission wavelength of commercial InGaN UV-LED.…”

Bright luminescence of Gd3+ sensitized RE3+-doped SiO2-BaGdF5 glass-ceramics for UV-LEDs colour conversion

“…Nano-materials doped with rare-earth (RE) ions are an important class of materials, for they present a broad range of applications, such as temperature sensors, solid-state lasers, optical amplifiers, lighting and displays, solar cells, labelling, and so on [1][2][3][4][5][6][7]. In particular, RE-doped oxyfluoride nano-glass-ceramics (nGCs) are currently being extensively investigated as blue or UV converting white light emitting diodes wLEDs in order to replace the traditional phosphors powder and organic resins, respectively [4,[8][9][10][11][12][13][14][15].…”