Dual-Color Emissive Tb3+- and Eu3+-Doped YVO4 Nanophosphors with Strain-Engineered Charge Transfer for Anticounterfeiting Application

Abstract Luminescent nanomaterials are increasingly recognized for their significance in secure labeling and photonic applications. This research is focused on the synthesis and characterization of Tb3+/Eu3+ codoped YVO4 nanophosphors, as well as assessing their potential for use in anticounterfeiting measures. Two compositions of YVO4:Tb3+/Eu3+ nanophosphors were synthesized and annealed at 900 °C for 4 h. Y0.95VO4:Tb0.043+/Eu0.013+ and Y0.95VO4:Tb0.033+/Eu0.023+ are analyzed using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), SEM-EDS, UV–vis, photoluminescence (PL), thermogravimetric analysis (TGA), and CIE techniques. XRD established phase purity and tetragonal structure. The band gap and Urbach energy (UE) values derived from UV–vis absorption data suggest that the synthesized materials possess favorable electrical as well as optical properties. PL studies showed strong red and green emissions, with Y0.95VO4:Tb0.033+/Eu0.023+ exhibiting ∼3 times higher red and green intensity, proving better energy transfer (ET). Under ultraviolet (UV) light, luminescent inks made from these materials produced invisible patterns that became visible, orange or reddish, depending on excitation wavelength and composition. Specifically for Y0.95VO4:Tb0.033+/Eu0.023+ nanomaterial, an excellent fluorescent orange emission was observed, which would be raised from the combination of green and red emissions. The results demonstrated that Tb3+/Eu3+ codoped YVO4 nanophosphors offer stable, tunable emission and are well suited for anticounterfeiting applications requiring covert UV-activated security features. This study, in comparison to prior research, illustrates the critical nature of host-activator compatibility, enhanced emission performance, and improved stability, emphasizing its potential for future optoelectronic applications.