Energy Transfer from Sm3+ to Eu3+ in Red-Emitting Phosphor LaMgAl11O19:Sm3+, Eu3+ for Solar Cells and Near-Ultraviolet White Light-Emitting Diodes

The red-emitting phosphor LaMgAl11O19:Sm3+, Eu3+ was prepared by solid-state reaction at 1600 °C for 4 h. The phase formation, luminescence properties, and energy transfer from Sm3+ to Eu3+ were studied. With the addition of 5 mol % Sm3+ as the sensitizer, the excitation wavelength of LaMgAl11O19:Eu3+ phosphor was extended from 464 to 403 nm, and the emission intensity under the excitation at 403 nm was also enhanced. The host material LaMgAl11O19 could contain the high doping content of Eu3+ (20 mol %) without concentration quenching. This energy transfer from Sm3+ to Eu3+ was confirmed by the decay times of energy donor Sm3+. The mechanism of energy transfer (Sm3+ → Eu3+) was proved to be quadrupole–quadrupole interaction. Under the 403 nm excitation at 150 °C, the emission intensities of the characteristic peaks of Sm3+ and Eu3+ in LaMgAl11O19:0.05Sm3+, 0.2Eu3+ phosphor were decreased to 65% and 56% of the initial intensities at room temperature, and the relatively high activation energy proved that th...