Visible luminescence and energy migration mechanism of Sm3+ in phospho-tellurite glasses by co-activating with Tb3+ ions for solid state lighting device applications

Abstract

Luminescence characteristics including the energy migration mechanism of Sm3+/Tb3+ co-activated BaO–PbO–Na2O-phospho-tellurite glasses have been reported. The XRD, FTIR, UV–VIS-NIR absorption, luminescence and CIE are examined to expose their structural and optical properties. The luminescence spectra of Sm3+/Tb3+ co-doped glasses show the green emission (Tb3+ ions) and reddish-orange colour emission (Sm3+ ions) upon dual excitation at 377 nm and 484 nm. The reduction of emission intensities (Tb3+ions) and self-emission quenching effect of Sm3+ ions have been observed when concentration of Sm3+ ions increases into the glass matrix which reveals the evidence of non-radiative energy transfer from Tb3+ (sensitizer) to Sm3+ (activator) ions. The phenomenon of energy migration is also verified with the help of Forster-Dexter theory. The chromaticity coordinates of all Sm3+/Tb3+ co-activated glasses shift from greenish to yellowish region with dependence of activator's concentration. The paper highlights that the present glasses can be utilized in light emitting devices.