Excitation Wavelength-Dependent Continuous Color-Tunable Luminescence of Fluorescent Dyes Encapsulated into Lanthanide Metal-Organic Framework for Anti-Counterfeiting

Excitation dependent luminescent materials, which have attracted significant scientific attention in the field of information security owing to information storage and luminescence properties. However, it remains a formidable challenge in developing excitation dependent luminescent materials with a simple synthesis method and predictably modulated luminescent outputs. Herein, a novel Ln3+/Fluorescent dyes@MOFs strategy is developed to generate excitation dependent continuous color-changing luminescent materials via a hydrothermal method and post-synthetic modification (PSM), based on metal-organic frameworks (MOFs) matrix doped with lanthanide cations and fluorescent dyes encapsulated into the lanthanide MOFs. The continuous proportional emission of mixed luminescence appeared within a single matrix in response to the different excitation wavelength and the proportional emission control (PEC) mechanism between the two luminescent centers is proposed. In addition, the photoluminescence platform demonstrates a distinct security method based on covert color that are controlled by distinct excitation wavelengths and excellent luminescence stability have also been verified in these new materials.