White light-emitting Dy 3+ -doped transparent chloroborosilicate glass: synthesis and optical properties

Abstract

Dy 3+ -doped chloroborosilicate glasses with the composition 35.7SiO 2 –25.5B 2 O 3 –17BaO–3.4K 2 O–3.4Al 2 O 3 –15BaCl 2 (mol%) were prepared using melt quenching technique. The glass transition temperature (T g ) was ~610°C. In UV–vis–NIR absorption spectra, characteristic absorption bands of Dy 3+ appeared at 322, 347, 364, 388, 795 and 880 nm due to spectral transitions from the 6 H 15/2 level to various higher levels of Dy 3+ ion. The excitation spectrum was recorded at within 200–550 nm by monitoring emissions at 576 nm. The excitation bands at 392, 428, 453 and 472 nm were attributed to the 6 H 15/2  →  4 I 13/2 , 4 G 11/2 , 4 I 15/2 and 4 F 9/2 transitions, respectively. Prominent emission bands were observed at wavelengths of 484, 576, 664 and 754 nm when excited at 447 nm. The bands correspond to the transitions 4 F 9/2  →  6 H 15/2 , 4 F 9/2  →  6 H 13/2 , 4 F 9/2  →  6 H 11/2 and 4 F 9/2  →  6 H 9/26 F 11/2 , respectively. The emitted light from all the samples was found to be white. Their color coordinates lie within the white range. The sample containing 0.5 wt% Dy 2 O 3 emitted white light with the color coordinates x = 0.351, y = 0.335, which are the very closest to pure white light and whose color temperature of 4716 K is similar to daylight. Such white light-emitting transparent glasses promise to be enormously useful for various photonic applications.