Smart quadruplicate information coding and hazard sensing, with dual UV/IR excitation, in 2D fine images of Eu3+/Tb3+/Zn2+ hyaluronan nanoaggregates and NaGdF4:Yb,Er nanoparticles

Abstract

Advanced data storage and anti-counterfeiting technologies are critical in addressing modern information safety. In this work, novel nanocomposites of Eu³⁺, Tb³⁺, Zn²⁺ and -hyaluronan for down-conversion and NaGdF₄:Yb,Er nanoparticles for up-conversion have been synthesized and applied for innovative anticounterfeiting luminescent inks. These inks exhibit excellent fluorescence under dual UV or NIR excitation, and sensitive quenching in response to some ions or compounds, enabling multi-level data encoding, reversible Cu²⁺ detection, and dynamic information concealment. Utilizing electrohydrodynamic (EHD) printing, we achieved precise patterns with line widths of approximately 20–50 μm, facilitating dynamic information concealment and secure data storage. The printed patterns, invisible under natural light, displayed distinct and bright fluorescence when stimulated by UV and NIR light, offering orthogonal readout capabilities for secure information retrieval. Additionally, the luminescent inks demonstrated remarkable sensitivity to Cu²⁺ ions, with fluorescence quenching efficiency reaching 85.3% at a Cu²⁺ concentration of 100 μg mL⁻¹. The quenching process was reversible upon introducing ethylenediaminetetraacetic acid (EDTA), enabling up to three cycles of fluorescence recovery and suppression with minor degradation (<15%) in intensity after repeated use. The high-resolution EHD printing technology combined with excellent sensing performance, such as a detection limit of 1.2 μg mL⁻¹ for Cu²⁺, enables a promising strategy for advancing intelligent information systems and hazardous ion detection. This work offers a versatile solution for secure information coding, anti-counterfeiting, and environmental sensing, providing a significant advancement in multifunctional luminescent materials, especially for smart quadruplicate information coding and hazard sensing, with dual UV/IR excitation.