Photoluminescent Y2O3:Eu3+@PVA composite dispersions and films for anti-counterfeiting ink applications

Abstract

The development of high-tech anti-counterfeiting inks to detect counterfeit products is a crucial task for almost every aspect of modern life around the world. Herein, we report the synthesis of photoluminescent xY2O3:Eu3+@PVA (x = 0, 1, 2.5, 5, 10, 15, and 20 wt%) composite dispersions and films and demonstrate their potential for anti-counterfeiting inks applications. Laser-synthesized m-Y2O3:Eu3+ nanoparticles (daver = 20.3 ± 6.9 nm) with strong red luminescence due to 5D0 → 7F0-4 transitions of Eu3+ were used as a pigment to create luminescent composites. Detailed photoluminescence properties of the obtained composite dispersions and films as a function of m-Y2O3:Eu3+ content were investigated in combination with SEM, EDX, UV–Vis and IR spectroscopy data. Tuning of the CIE coordinates of xY2O3:Eu3+@PVA is observed by changing the excitation wavelength. The results of SEM showed that the photoluminescent nanoparticles were uniformly distributed in the PVA film. Photoluminescent m-Y2O3:Eu3+-doped PVA composite inks can be applied via spray, brush, and screen-printing techniques to create security features on various surfaces, including glass, ceramics, paper, plastics, and currency notes. These inks remain stable for at least four months and offer a distinctive luminescent signature that is challenging to replicate, owing to the unique photoluminescence spectrum of Eu3+ in the monoclinic Y2O3 polymorph.