Preparation and luminescence properties of Eu3+-doped calcium bismuth borate red-light-emitting glasses for WLEDs

Abstract Calcium bismuth borate glasses doped with Eu 3 + were prepared using a rapid melt quenching technique. The general physical properties of the glasses, including density, molar volume, and refractive index, were studied. Furthermore, the structural and optical properties as well as the thermal stability of the glasses were investigated. Eu 3 + melts homogeneously in the glass samples and acts as an effective activator. The largest absorption and excitation peak appears at 465 nm in the spectra, and intense emission occurs at 613 nm. The excited and emitted spectral intensities were observed to first increase and then decrease with increasing Eu 3 + concentration. The glass sample containing 3% (mole fraction) Eu 2 O 3 exhibited the optimum doped concentration, and it was determined that concentration quenching does not result from the non-relaxation of the 5 D 0 energy level. The glass structures were observed to become more compact with an increasing Eu 3 + concentration, and the symmetries decreased. Overall, the glasses maintained the amorphous states. [BO 3 ], [BiO 3 ], [BO 4 ] and [BiO 6 ] units appear in the glass samples, and the variation in the [BiO 6 ] units shows an inflection point. Briefly, the glass sample containing 3% Eu 2 O 3 exhibits many beneficial properties, such as high thermal stability, an appropriate refractive index and the ability to match the blue-light emission of LED chips. The glass therefore expected to be as candidate for white light emitting diode glass ceramic applications.