Construction of RhB derived multicolor carbon quantum dots @ up-conversion nanoparticle NaYF4:Yb3+, Er3+ for dual-model anti-counterfeit applications

The development of luminescent materials exhibiting dual luminescent modes for anti-counterfeiting purposes is of significant importance. In this study, we introduce and synthesize hybrid materials composed of carbon quantum dots and up-conversion particles (CDs@UCNP). By combining Yb 3+ and Er 3+ doped NaYF 4 up-conversion nanoparticles with carbon quantum dots, we successfully prepared a kind of fluorescent materials that demonstrate dual-mode fluorescence. By changing the fluorescent color of carbon quantum dots to achieve different down-conversion (DC) luminescence, we produced three dual-mode luminescent materials: BCDs@UCNP, YCDs@UCNP, and RCDs@UCNP, which exhibit blue, yellow, and red DC luminescence when exposed to 365 nm ultraviolet light, alongside green or red up-conversion luminescence under 980 nm laser. Furthermore, we formulated three water-based inks utilizing water-based acrylic emulsion as a binder. These inks exhibit dual-mode tunable luminescence properties, thereby enhancing the security of the printed patterns and positioning them as promising candidates for anti-counterfeiting applications.