Site‐Selective Occupancy of Eu²⁺ toward High Luminescence Switching Contrast in BaMgSiO₄‐Based Photochromic Materials

Abstract

Luminescent inorganic photochromics have great potential applications in 3D optical memory due to their excellent thermal stability and chemical resistance. Nevertheless, constructing inorganic photochromics with a high luminescence switching contrast remains challenging for optical information storage. Understanding inherent relationships between microenvironment changes, photophysical material properties, and rational control of their luminescence properties are crucial to address these issues. This paper proposes an effective strategy to significantly improve the luminescence switching contrast by more than 300% by site‐selective occupancy engineering on BaMgSiO4:Eu2+ photochromic materials. An effective energy transfer process is established between luminescent and photochromic units, which may provide new insights for designing high‐performance optical storage systems. The fabricated flexible films exhibit excellent waterproof, flexibility, and stretchability characteristics, accompanied by reversible color switching and larger color contrast. Optical data storage can be not only visually encoded and decoded on the flexible films by 405 and 532 nm LED excitation, respectively. Writing, erasing, and reading strategies for flexible films are particularly suitable for complex application environments in optical storage and rewritable flexible devices.

Entirely Reversible Photochromic Glass with High Coloration and Luminescence Contrast for 3D Optical Storage

“…When the irradiation times ranged from 1 to 5, 15, 25, 30, and 60 s, the calculated Δ R t reached 50%, 80%, 86%, 90%, 91%, and 91%, respectively. A saturated photochromism of 91% was obtained at a stimulation time of 30 s (Figure b), exhibiting a remarkably large transmittance contrast in comparison with previous inorganic photochromic nanoparticles of thin films to bulk ceramics. ,,− From Supplementary Video 1, we can see that the color of the Eu-Ag glass was modified from light yellow to opaque black upon 365 nm irradiation for 30 s.…”

Photochromic and Electric Field-Regulating Luminescence in High-Transparent (K,Na)NbO3-Based Ferroelectric Ceramics with Two-Phase Coexistence

“…On the right, the energy transfer (ET) theory shows that the dipole–dipole excited ET (EET) from the donor to the acceptor is the most important. − When the distance between the luminous center and the color center is close enough, effective EET will occur, resulting in quenching of luminescence. The sample with x = 0.5 and x = 1.5 has a lower transmittance, indicating more vacancy defects, and thus lots of color centers will be generated after illumination, which leads to the larger Δ R value. Although these trapped carriers are in an unstable metastable state, it is difficult to recover them by illuminating near room temperature, so this can only be completed by high-energy thermal stimulation (300 °C, 5 min) .…”

“…In addition, Shen et al adjust the luminescence intensity of Er 3+ /Yb 3+ -doped SrBi 8 Ti 7 O 27 ceramics through illumination and electric field. Multistimulus responses under illumination, electric/magnetic field, and mechanical stress in ferroelectric materials can convert energy to achieve smart devices, − which thus have great potential in the next generation of data storage, optical switching, anticounterfeiting, and biological imaging …”

Immobilization of lanthanide doped aluminate phosphor onto recycled polyester toward the development of long‐persistent photoluminescence smart window

“…A light-induced color shift that occurs to a certain material under an excitation source and after that returns to its original color when the excitation supply is removed is known as photochromism. [20,21] Photochromism has been an intriguing technique for smart materials, like packaging, ophthalmic lenses, electronic displays, sensors, and sunglasses. Smart fabrics, security barcodes for brand protection, ultraviolet (UV) protection, and military camouflage have all benefitted from this extraordinary knowledge of photochromism.…”