Synthesis and photoluminescence properties of a novel double perovskite NaGdMgTeO6:Sm3+red-emitting phosphor for plant growth LEDs and w-LEDs

This research used solid-state reaction methods to synthesize a series of double perovskite structure NaGdMg-TeO6:xSm3+ (x = 0.5-30 mol%) phosphors. A systematic study was conducted on the crystal structure, phase purity, photoluminescence (PL) properties, concentration quenching mechanism, color purity, thermal stability, and inner quantum efficiency (IQE) of the samples. Under 405 nm excitation, NaGdMgTeO6:Sm3+ phosphors showed strong red emission at 648 nm, attributed to the 4G5/2 & RARR; 6H9/2 transition of Sm3+ ions. The optimal luminescence intensity was achieved at the dopant concentration of 1 mol%, and the dipole-dipole interaction mechanism contributed to the concentration quenching process. High color purity of more than 99.8% and appropriate Commission International de L'Eclairage (CIE) chromaticity coordinates were obtained for the NaGdMgTeO6:Sm3+ phosphors. High thermal stability and activation energy (Ea = 0.293 eV) were found to be excellent characteristics of the phosphors. Ultimately, the fabricated red LED in this study revealed superior spectral matching with the phytochrome Pr. The white light-emitting diode (w-LED) prepared had a high color rendering index (Ra) of 90 and a suitable correlated color temperature (CCT) of 5337 K. As a result, these phosphors are potentially suitable for use in plant growth LEDs and w-LEDs.