Multiple stimuli-responsive double perovskite structured Ca2MgWO6: x % Eu3+ (x = 1–11 mol) red-emitting luminescent systems to combat counterfeiting

Abstract

The rapid escalation of counterfeiting activities in recent years has posed significant challenges across diverse fields, such as pharmaceuticals, currency, luxury goods, and electronics. In response, inorganic phosphors have emerged as promising tools to combat counterfeiting due to their inherent durability and stability. The present work focuses on the synthesis of Ca₂MgWO₆: x % Eu³⁺ (x = 1–11 mol) luminescent systems via a gel-combustion route. The structural analysis of the synthesized luminescent systems confirmed a monoclinic crystal phase with a P2₁/n space group. The morphological study of the luminescent system revealed a network-like structure comprising interconnected particles. Photoluminescence emission spectra show a prominent red emission peak at 616 nm, corresponding to the ⁵D₀ → ⁷F₂ 4f–4f electronic transition of Eu³⁺ ions in the host matrix. The emitted red light demonstrates a color purity and quantum efficiency of 93.1 % and 77.41 %, respectively. The anti-counterfeiting security patterns were developed using the Ca₂MgWO₆: x % Eu³⁺ (x = 9 mol) luminescent system, which showcases virtually invisible under normal light. However, developed patterns exhibit vivid red luminescence when exposed to multiple stimuli i.e., ultraviolet light at 365 and 395 nm wavelength, which envisages the versatility of the systems for enhancing product authentication and protecting against fraudulent activities across multiple industries. The aforementioned results demonstrated the efficacy of Ca₂MgWO₆: Eu³⁺ luminescent systems for integration into advanced security measures.