Single phased vivid red-emitting CaLa2ZnO5:Eu3+ nanophosphor: WLEDs, visualization of latent fingerprints and anti-counterfeiting applications

Abstract

A novel class of cutting-edge materials known as photoluminescent (PL) nanophosphors (NPs) based on inorganic compounds has the potential to be used in a variety of industries, including chemo sensors, optical devices, drug delivery systems, anticounterfeiting inks (AC), and bioimaging. In the present work, we report a simple propellent combustion method for the preparation of CaLa2ZnO5:Eu3+ (1–9 mol%) (CLZO:Eu) NPs. The optimized powders are utilized for strategic applications such as white light emitting diodes (WLEDs), latent Finger Print (LFP) detection and anti-counterfeiting (AC) applications. According to the PL spectral profiles, the dazzling red emission has been observed at 626 nm (5D0→7F2) from the CLZO:Eu NPs under the excitation of 395 nm. The ideal activator concentration is determined to be 5 mol%, and the quadrupole-quadrupole interactions are attributed for the concentration quenching that resulted from the over doping. The CIE coordinates (x-y) are determined to be (0.6206, 0.3732) for CLZO:5Eu NPs. The correlated colour temperature (CCT) value for the optimized sample is determined to be between 2000 and 5000 K, indicating that it may be a more suitable red component for warm white light applications. The fabricated PL NPs for AC labels exhibited strong fluorescence emission and good stability, under UV light, different chemical environments, and ambient environments making them suitable for a variety of uses, including environmentally friendly PL inks for anti-counterfeiting technologies. CLZO:5Eu NPs, on the other hand, can clearly distinguish between grooves and ridges and recognize the detail of levels 1–3. The overall results clearly showed that, the present material has great potential for multilevel anticounterfeiting strategies to achieve high-security encryption.