CaY2Sb2(ZnO4)3:Sm3+ phosphors with high thermal stability for high CRI w-LEDs and visualization of latent fingerprints

A novel series of samarium-activated orange-red emitting CaY 2 Sb 2 (ZnO 4 ) 3 (CYSZO) phosphors has been successfully synthesized by the high-temperature solid-state method. The phase purity, spectroscopy, and morphological properties of the phosphors have been extensively characterized. When excited at 407 nm, CYSZO:Sm 3+ samples exhibited a pronounced orange-red emission peak at 610 nm, this corresponding to the typical 4 G 5/2  →  6 H 7/2 both magnetic-dipole and electric-dipole transitions of Sm 3+ ions. The optimal doping concentration was established as 10 mol%. The quenching mechanism is attributed to the interaction of the nearest-neighbor ions. The prepared sample showed a remarkable internal quantum efficiency (IQE) of 68.63 % and exceptional thermal stability at working temperature of the LEDs. As the Sm 3+ concentration increased, the decay time decreased correspondingly, ranging from 2.45 ms to 1.40 ms for concentrations ranging from 0.6 to 40 mol%. The phosphor materials exhibited high color purity, as evidenced by the Commission International de L'Éclairage (CIE) chromaticity coordinates. The synthesized white light-emitting diode (w-LED) exhibited an impressive color rendering index (CRI) of 96 and a desirable correlated color temperature (CCT) of 5674 K. Furthermore, the CYSZO:10 mol%Sm 3+ @oleic acid phosphor-stained latent fingerprint (LFP) images show excellent visualization capabilities on various surfaces with high contrast and long-term stability. These results highlight the potential of CYSZO:Sm 3+ phosphors to serve as a promising orange-red material for w-LED applications and LFP detection.