Combination of broad emission bands of Ti3+,4+/ Eu2+,3+ co-doped OH− free low silica calcium aluminosilicate glasses as emitting phosphors for white lighting devices

Highlights: • Ti^3+,4+/Eu^2+,3+ low silica calcium aluminosilicate glass showed broad white lighting. • The excitation at 300 nm produced emission embracing very well the visible region. • The color temperature varied from 4995 to 6609 K • The luminescence quantum yield was measured to be 42%. • The developed glass is a candidate for artificial lighting. -- Abstract: In this report, Ti^{3+, 4+}/Eu^{2+, 3+} co-doped OH⁻ free low silica calcium aluminosilicate glasses (LSCAS) were synthesized and their optical properties investigated aiming applications as phosphors for white light generation. This research explores the possibility of combining the broad emission bands in the visible of these glasses co-doped with Ti^3+,4+/Eu²⁺ ions with those in the red emitted by Eu³⁺, in addition to the high luminescence quantum yield they present. The excitation and emission results show that exciting the samples at 300 nm, a broad emission band is generated, embracing very well the visible region. The emission spectra were analyzed by (x-y) CIE-1931 chromaticity diagram and the color rendering index (CRI) presented Ra values up to 80, with the correlate color temperature (CCT) varying from 4995 to 6609 K. The luminescence quantum yield determined by Thermal Lens Spectroscopy showed values of 38 and 42% for the samples with (in wt%) 0.1Eu₂O₃-2.0TiO₂ and 0.5Eu₂O₃-2.0TiO₂, respectively. Finally, the energy transfer processes between these luminescent ions were discussed, highlighting the potential of the Eu–Ti LSCAS glasses as candidates for the development of devices for white light generation.