Optical Materials (2012)

Thermal quenching and luminescence lifetime of saturated green Sr1−xEuxGa2S4 phosphors
Jonas J. Joos, Katrien W. Meert, Anthony B. Parmentier, Dirk Poelman, Philippe F. Smet
Optical Materials 34 (2012) 1902-1907

Due to the lack of efficient green emitting solid state light sources, conversion phosphors emitting saturated green emission are highly interesting, both for display and signalling applications. In this work, we study the luminescence properties of Sr1−xEuxGa2S4 phosphors over a wide dopant concentration range (x = 0.01–0.3), as function of temperature. The phosphors show a saturated green emission over the entire studied range, with a typical peak wavelength around 536 nm and a FWHM of 50 nm. The internal quantum efficiency is 71% for x = 0.04. For this concentration, the emission intensity at 400K is still 90% of the intensity at room temperature. By measuring both decay and thermal quenching profiles as a function of europium concentration, we were able to explain the emission properties on the basis of the local environment of the europium ions in the lattice.

Keywords: Conversion Phosphor, LED, Displays, Europium, Thermal Quenching, Thiogallate

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