Spectroscopic investigation and interest of Pr3+-doped calcium aluminosilicate glass

In this report, Pr3+ -doped calcium aluminosilicate (CAS) glasses were synthesized and their spectroscopic properties investigated. The present subject was motivated by the red emission of the Pr3+ ion that can be combined with the green-yellow emission of other luminescent ions like Ce3+ or Eu2+ for white light generation. This combination of materials has been required since commercial diode devices for white lighting exhibit low color rendering index (CRI) and high correlated color temperature (CCT) due to their low emission intensity in the red region. The results showed that when Pr3+-doped CAS glasses are excited at 445 nm, red and green broadband emissions (FWHM similar to 1300 and 1800 cm(-1), respectively) with a strong dependence on the ion concentration can be observed. The (x, y) coordinates in the CIE-1931 chromaticity diagram changed from (0.61, 0.36) to (0.47, 0.41) when the Pr3+ concentration varied from 0.2 to 2.0 wt.%, what was explained in terms of cross-relaxation mechanisms between Pr3+ ions. The luminescence quantum yield (QY), in the visible range from 450 to 800 nm, of the Pr3+-doped CAS glass was determined by an integrating sphere as 0.37, which is a relatively high value for Pr3+-doped glasses. At high Pr3+ concentrations, the studied system is appropriate to be combined with other green-yellow phosphor material for white light generation.