Eu²⁺/Eu³⁺-Based Smart Duplicate Responsive Stimuli and Time-gated Nanohybrid for Optical Recording and Encryption

Abstract

With the rapid development of information science, it is urgent that memory devices possessing high security, density, and desirable storage ability should be developed. In this work, a smart duplicate response of stimuli has been developed and a time-gate nanohybrid based on variable valence Eu 2+ /Eu 3+ coencapsulated has been fabricated and acts as active material in the multilevel and multidimensional memory devices. The luminescence lifetime of Eu 3+ in this nanohybrid gave a stimuli response due to which the energy level of the coordinated ligand could be modulated. Furthermore, by a simple sintering procedure, Eu 3+ was partially in situ reduced to Eu 2+ with a short lifetime in the system. And the in situ reduction ensured both Eu 3+ and Eu 2+ ions' uniform distribution in the nanohybrid and simultaneous response upon light excitation of variable valence Eu ions. Interestingly, Eu 3+ revealed a prolonged lifetime because of the presence of an energy-transfer effect of Eu 2+ → Eu 3+ . Such a nanohybrid had abundant luminescent properties, including the short lifetime of Eu 2+ , the energy transfer from the Eu 2+ to Eu 3+ ions, and the stimuli response of the Eu 3+ lifetimes when exposed to acidic or basic vapor, thus giving birth to interesting recording and encryption performance in spatial−temporal dimensions. We believe that this research will point out a new direction for the future development of multilevel and multidimensional optical recording and encryption materials.

Manipulating Electroluminochromism Behavior of Viologen‐Substituted Iridium(III) Complexes through Ligand Engineering for Information Display and Encryption

“…Modulation of photoluminescence by external stimuli has attracted great research interest in the fields of display, [ 1–3 ] security, [ 4–6 ] memory devices, [ 7,8 ] biological probes, [ 9,10 ] and bioimaging reagents. [ 11,12 ] Electrical stimulus is one of the most important and promising means of regulating photoluminescence owing to its facile and precise operation and can be easily integrated in optoelectronic devices.…”

Fluorescence Lifetime-Tunable Water-Resistant Perovskite Quantum Dots for Multidimensional Encryption

“…Typical materials reported using fluorescence lifetime for encryption include rare-earth metal complexes and carbon dots. 12,13 However, most of the existing materials exhibit distinguishable fluorescence spectral change when designed to show different fluorescence lifetimes. 10,14 This fact greatly reduces the security of information encryption, as the temporal encrypted data may be cracked from the fluorescence spectra analysis.…”

“…One attractive way to increase the data storage capability and the security of data encryption is to introduce the temporal dimension of fluorescent signals into optical multiplexing. , Ideal temporal dimension data encryption requires light-emissive materials with tunable fluorescence lifetime but identical fluorescence spectra. Typical materials reported using fluorescence lifetime for encryption include rare-earth metal complexes and carbon dots. , However, most of the existing materials exhibit distinguishable fluorescence spectral change when designed to show different fluorescence lifetimes. , This fact greatly reduces the security of information encryption, as the temporal encrypted data may be cracked from the fluorescence spectra analysis. Finding the suitable material to store data in the temporal dimension remains a challenge.…”

Photoluminescence and Stoichiometry Correlation in Nanocrystalline EuOx Thin Films: Tunable Color Emission

“…Luminescence from rare earth Eu (europium) ions holds great promises for applications compatible with silicon technologies, such as optical recording and encryption, white cathodoluminescence emission, and phosphors with excellent stability and color performance . To answer this interest, Eu-doping in Si-based materials has been a very active field of research that has included studies not only of the photoinduced luminescence but also of the electrical excitation of oxides suitable for Si integration doped with trivalent Eu (Eu 3+ ), and more recently, the cathodoluminescence of oxides and oxynitrides doped with divalent Eu (Eu 2+ ) has been reported .…”