Synthesis and Optical Characterization of Novel Orange-Red Emitting LaGaSnO:Sm Phosphors with Abnormal Thermal Quenching and Application To w-LEDs.

This research successfully prepared a novel series of LaGaSnO:xSm phosphors (x = 1, 2, 5, 10, 15, 20, 25, and 30 mol%) through high-temperature solid-state synthesis. This series of phosphors exhibited excellent phase purity. The excitation spectrum of LaGaSnO:Sm showed an optimal excitation wavelength at 403 nm. Four distinct peaks (566, 598, 644, and 708 nm) were observed in the emission spectrum, with the most prominent peak appearing at 598 nm, corresponding to the G-H radiative transition of Sm ions. The LaGaSnO:2 mol%Sm was the optimal sample for effective optical performance. The concentration quenching effect is caused by nearest neighbor ion interactions. Within the temperature range of 300 to 480 K, the LaGaSnO:Sm phosphor demonstrated very stable luminescence, with little changes in luminous intensity and Commission Internationale de l´Eclairage (CIE) chromaticity coordinates. The synthesized phosphors show remarkable thermal stability with an activation energy barrier of E = 0.51 eV, displaying unusual thermal quenching characteristics. These properties make them a highly potential candidate for white light-emitting diode (WLED) applications.