Information Storage Applications Research Articles

Mechanochromic 3D Soft Photonic Crystals Enabled Anticounterfeiting and Encryption Information Storage

AbstractInspired by the color‐changing abilities of natural organisms, this research focuses on the design and fabrication of mechanochromic liquid crystal photonic crystal thin films with periodic self‐assembly structures. Benefiting from its unique 3D self‐assembled structure with a body‐centered cubic lattice, BP I film exhibits excellent mechanical properties, characterized by superior elasticity and toughness due to the presence of rigid and flexible microdomains and suitable dislocation line volumes. As the strain increases, the structural color of the BP I film demonstrates a repeatable and rapid shift from red to blue, covering the entire visible light spectrum with high reflectivity. The incorporation of fluorescent molecules further enhances the mechanical properties and endowing the film with circularly polarized luminescence under UV light irradiation. Utilizing different fluorescent dyes as inks, arbitrary patterned writing can be performed on the BPI film, enabling specific information hiding and encryption. The prepared label exhibits excellent environmental stability, presenting promising applications in information storage, anti‐counterfeiting, and flexible 3D displays. The study may contribute to a deeper understanding of the relationship between microstructure, mechanical deformation, and optical properties, potentially advancing the development of innovative responsive materials and multifunctional devices.

Strategy for Simple Control of High Performance PQ/PMMA Holographic Media.

Holographic data storage technology is a cost-effective solution for long-term archival data storage. However, the development of suitable holographic recording materials remains a challenge. Among these materials, phenanthraquinone-doped poly(methyl methacrylate) (PQ/PMMA) stands out due to its low cost and controllable thickness. Nevertheless, its limited photosensitivity and diffraction efficiency hinder its widespread application. In order to solve these problems, we put forward a kind of convenient and simple, low cost strategy, by adding plasticizer N,N-dimethylformamide (DMF) for preparation of DMF-PQ/PMMA photopolymer, avoid the use of complex compounds. The addition of DMF not only influences the thermal polymerization stage but also forms weak interactions with PQ during the photoreaction process, thereby enhancing the holographic performance of DMF-PQ/PMMA. Consequently, we achieved a remarkable 9.1-fold increase in photosensitivity (from ∼0.35 to 3.18 cm J-1), improved diffraction efficiency by 20% (from 65% to 80%), and reduced volume shrinkage by a factor of 8 (from 0.4% to 0.05%). Furthermore, utilizing a collinear holographic storage system with multiplexing shift at a scale of 5 μm resulted in an impressively low minimum bit error rate (BER) of only 0.36% (with an average BER of 1.4%), highlighting the fast processing capability and potential for low BER applications in holographic information storage using DMF-PQ/PMMA.

Deep-trap ultraviolet persistent phosphor for advanced optical storage application in bright environments

Extensive research has been conducted on visible-light and longer-wavelength infrared-light storage phosphors, which are utilized as promising rewritable memory media for optical information storage applications in dark environments. However, storage phosphors emitting in the deep ultraviolet spectral region (200–300 nm) are relatively lacking. Here, we report an appealing deep-trap ultraviolet storage phosphor, ScBO3:Bi3+, which exhibits an ultra-narrowband light emission centered at 299 nm with a full width at half maximum (FWHM) of 0.21 eV and excellent X-ray energy storage capabilities. When persistently stimulated by longer-wavelength white/NIR light or heated at elevated temperatures, ScBO3:Bi3+ phosphor exhibits intense and long-lasting ultraviolet luminescence due to the interplay between defect levels and external stimulus, while the natural decay in the dark at room temperature is extremely weak after X-ray irradiation. The impact of the spectral distribution and illuminance of ambient light and ambient temperature on ultraviolet light emission has been studied by comprehensive experimental and theoretical investigations, which elucidate that both O vacancy and Sc interstitial serve as deep electron traps for enhanced and prolonged ultraviolet luminescence upon continuous optical or thermal stimulation. Based on the unique spectral features and trap distribution in ScBO3:Bi3+ phosphor, controllable optical information read-out is demonstrated via external light or heat manipulation, highlighting the great potential of ScBO3:Bi3+ phosphor for advanced optical storage application in bright environments.

Air-stable and ultralong room-temperature phosphorescence from doped poly(methyl methacrylate) for visual detection of volatile organic compounds

Room-temperature phosphorescence (RTP) has attracted significant attention due to its intriguing luminescence properties and potential applications in information storage, encryption, and sensing. Herein, we reported the facile fabrication of air-stable and ultralong RTP polymer films that exhibited remarkable and multiple stimuli responses. These films were composed of poly(methyl methacrylate) (PMMA) physically crosslinked with emitter molecules, resulting in transparent and flexible RTP materials. Remarkably, these polymer films emitted a bright RTP with a lifetime of 2.93 s, which was the best performance of PMMA materials reported. This exceptional performance was attributed to the abundant and robust physical interactions between the polymer chains and emitter molecules. Intriguingly, the RTP of these polymer films could be activated through consecutive UV irradiation, and quenched via thermal annealing in a controlled manner. The UV-activated RTP remained stable in humid air at room temperature over 1 week. Notably, the RTP of these flexible polymer films was sensitive to volatile organic compound (VOC) vapor. Upon exposure to VOC vapor, the RTP intensity of the polymer films rapidly decreased due to the disruption of their physically crosslinked microstructure. This unique sensitivity enabled the visual detection of VOCs in air by utilizing RTP polymers for the first time.

Highly efficient and thermally stable photonic ceramic by controllable and full crystallization from glass

Polycrystalline ceramics are promising for a diverse range of applications in solid state laser, lighting, scintillator and optical storage. Unfortunately, current ceramic elaborations involves strict and complex synthetic procedures such as ultra-high pressure and vacuum processing. Here, we realize the tune of MgAl2Si4O12 and Mg2Al4Si5O18 phase formation in a glass by controlling the two crystal nucleation and growth individually, and obtain a polycrystalline non-stoichiometric Mg2-x/2Al4-xSi5+xO18:Eu2+ translucent ceramic by virtue of complete and congruent crystallization of the glass. Microstructural characterizations verify that the resulting ceramic exhibits dense and closely stacked micrometer-scale crystallites with very thin grain boundary structure. Chemical composition analysis by energy dispersive X-ray spectrometry revels the grain's composition is highly deviated from the stoichiometric Mg2Al4Si5O18, with atomic ratio Mg/Al/Si of 1.00: 1.46: 2.70. The precipitated non-stoichiometric Mg2-x/2Al4-xSi5+xO18, structurally having infinite channels z = 0.25 or 0.75 sites that run parallel to the c-aix, provides an robust crystal-field environment for Eu2+ 5d-4f transition. As a consequence, the ceramic produces intense emission with photoluminescence quantum yield (PLQY) up to 90 %, and excellent thermal stability emission with 70.1 % emission intensity at 420 K relative to that at room temperature, demonstrating it can be applied in high power lighting application with improved light quality by employing the ceramic as a color converter. Moreover, the ceramic also exhibits thermally stimulated luminescence at temperature reaching up to 700 K, originating from the deep electronic traps in Mg2-x/2Al4-xSi5+xO18 lattice with estimated trap depth of 0.73eV and 0.97eV. We also demonstrate the ceramic is hopeful for optical information storage application as the storage information can be retain well without vulnerable by the fluctuations of external environments due to the deep traps.

BiFeO3/SrTiO3 superlattice-like based ferroelectric memristors with pronounced artificial synaptic plasticity

Memristors are attracting widespread attention for their multilevel storage capacity and synaptic learning ability. Ferroelectric memristors, with resistance switching based on polarization reversal, offer uniform threshold voltage and analog resistance modulation. By preparing superlattice-like ferroelectric films, the ferroelectric properties can be significantly enhanced, thereby improving the memristive characteristics. In this study, the constructed BiFeO3/SrTiO3 (BFO/STO) superlattice-like structure increases the remanent polarization by approximately 200 % compared to a single-layer BFO structure, as well as the dramatically enhanced resistance switching performance. Notably, the Pt/(BFO/STO)2/NSTO device shows superior storage performance, with extended endurance (1000 cycles), reliable retention (10000 seconds) and fundamental synaptic behaviors being demonstrated. Finally, simulations for handwritten digit recognition classification, involving modulation of conductance to vary synaptic weights, achieve an impressive accuracy of 87.46 %, showing great promising for applications in information storage and neuromorphic computing.

Generating grating in cavity magnomechanics

Abstract We investigate the phenomenon of magnomechanically induced grating (MMIG) within a cavity magnomechanical system, comprising magnons (spins in a ferromagnet, such as yttrium iron garnet), cavity microwave photons, and phonons (Li et al 2018 Phys. Rev. Lett. 121 203601). By applying an external standing wave control, we observe modifications in the transmission profile of a probe light beam, signifying the presence of MMIG. Through numerical analysis, we explore the diffraction intensities of the probe field, examining the impact of interactions between cavity magnons, magnon-phonon interactions, standing wave field strength, and interaction length. MMIG systems leverage the unique properties of magnons, and collective spin excitations with attributes like long coherence times and spin-wave propagation. These distinctive features can be harnessed in MMIG systems for innovative applications in information storage, retrieval, and quantum memories, offering various orders of diffraction grating.

QRGB+: Advanced QR Code Generator with RGB Color Method in Python to Expand Data Capacity

The present work entitled QRGB, consists of the development of an application in Python for the generation of QR codes using the additive color generation (RGB) method. This innovative method allows increasing the density of information stored in QR codes by using three color layers (red, green and blue), each representing a different set of data. QRGB offers an efficient and secure solution for storing and transmitting large amounts of information in limited spaces, significantly improving the capabilities of traditional black and white QR codes. By using three layers of colors, QRGB codes can store up to three times more information in the same space. This technique not only increases storage capacity but also improves information security, making it difficult to forge or manipulate the code. The overlay of multiple data layers allows redundancy to be implemented, increasing the robustness of the code against damage or reading errors. QRGBs are especially useful in applications that require the transmission of large amounts of data in limited spaces, such as in the packaging industry, digital business cards, and interactive advertising. Additionally, they have great potential in areas such as document and banknote security, where the authenticity and integrity of information are crucial. These points provide a solid foundation for understanding the innovation and advantages of colored QR codes (QRGB) compared to traditional QR codes, highlighting their applicability and potential in various sectors. This article presents a novel method for encoding and decoding information using a QRGB code, which involves the generation of three independent QR codes and their superimposition according to the additive color system (RGB). The research highlights the challenges encountered during the encoding and decoding processes due to the lack of specific libraries in Python, which required the creation of a custom solution using open source tools. The implementation takes advantage of Python and its libraries: qrcode[pil] to generate QR codes with the Pillow dependency for image manipulation, Pillow to open, manipulate and save different image formats, and opencv-python to perform tasks such as image processing and object detection. Despite facing issues with color mixing and accurate information retrieval, the proposed method demonstrates a significant increase in data density within a single QR code. Future work will focus on optimizing the algorithm and exploring potential applications in data security and high-density information storage. This Python script is designed to generate and decode QR codes with a logo overlay using a graphical user interface (GUI) built with Tkinter. The script combines several functionalities, such as creating QR codes, overlaying a logo, combining QR images of different colors, and manually decoding combined QR codes.

Emerging Multifunctionality in 2D Ferroelectrics: A Theoretical Review of the Interplay With Magnetics, Valleytronics, Mechanics, and Optics

Abstract2D ferroelectric materials present promising applications in information storage, sensor technology, and optoelectronics through their coupling with magnetics/valleytronics, mechanics, and optics, respectively. The integration of 2D ferroelectrics with magnetism enhances data storage density in memory devices by enabling electric‐field‐controlled magnetic states. Ferroelectric‐valley coupling holds promise for high‐speed, low‐energy electronics by leveraging the electrical control of valley polarization. Ferroelectric‐strain coupling results in various polar topologies, with potential applications in high‐density data storage technologies and sensor devices. Moreover, the coupling between ferroelectrics and optics facilitates the development of nonlinear photonics based on ferroelectric materials. This review summarizes the latest theoretical progress in the coupling mechanisms, including the Dzyaloshinskii‐Moriya‐interaction‐induced magnetoelectric coupling, symmetry‐linked ferroelectric‐valley coupling, ferroelectric‐strain‐coupling‐generated polar topologies, and second‐harmonic generation through ferroelectric‐light interactions. The current challenges and future opportunities in harnessing the coupling in 2D ferroelectric materials for multifunctional applications are provided.

Room temperature skyrmions in Pt/Co/Gd multilayers and their non-volatile electric-field creation in multiferroic heterostructure

This study delves into the formation and control of magnetic skyrmions within a Pt/Co/Gd multilayer system. By systematically varying the thickness of the Co layer, we observe the emergence of Néel-type skyrmions, characterized by confined magnetization curls with Lorentz transmission electron microscopy. The interplay between magnetic anisotropy, Dzyaloshinskii–Moriya interaction, and antiferromagnetic coupling at material interfaces is investigated to understand the stability and manipulation of these fascinating spin configurations. Additionally, we explore the impact of an external electric field on skyrmion generation, demonstrating a pathway for their controlled creation. The observed electric-field control of skyrmions offers a promising approach to achieving non-volatile magnetic states with low power consumption and negligible Joule heating. These findings hold great potential for advancing spintronics and magneto-electric devices, enabling modulation of skyrmions for information storage and processing applications.

Hybrid metal halide family with color-time-dual-resolved phosphorescence for multiplexed information security applications

Luminescent materials with engineered optical properties play an important role in anti-counterfeiting and information security technology. However, conventional luminescent coding is limited by fluorescence color or intensity, and high-level multi-dimensional luminescent encryption technology remains a critically challenging goal in different scenarios. To improve the encoding capacity, we present an optical multiplexing concept by synchronously manipulating the emission color and decay lifetimes of room-temperature phosphorescence materials at molecular level. Herein, we devise a family of zero-dimensional (0D) hybrid metal halides by combining organic phosphonium cations and metal halide tetrahedral anions as independent luminescent centers, which display blue phosphorescence and green persistent afterglow with the highest quantum yields of 39.9 % and 57.3 %, respectively. Significantly, the luminescence lifetime can be fine-tuned in the range of 0.0968–0.5046 μs and 33.46–125.61 ms as temporary time coding through precisely controlling the heavy atomic effect and inter-molecular interactions. As a consequence, synchronous blue phosphorescence and green afterglow are integrated into one 0D halide platform with adjustable emission lifetime acting as color- and time-resolved dual RTP materials, which realize the multiple applications in high-level anti-counterfeiting and information storage. The color-lifetime-dual-resolved encoding ability greatly broadens the scope of luminescent halide materials for optical multiplexing applications.

Simultaneous Dynamic Display of Meta‐Hologram and Meta‐Nanoprinting with High Frame Rate

AbstractDynamic holography can reconstruct realistic and highly interactive 3D scenes, offering a promising way for future display. Emerging metasurface with small pixel size and powerful light modulation capability demonstrates performance superior to traditional spatial light modulators, but dynamic meta‐holography with high information capacity and high frame rate remains a challenge. This paper presents a design scheme combining a preset polarization‐dependent metasurface with a high‐speed projection module to realize smooth dynamic display at multiple polarization states. With the projection module, the system can achieve dynamic meta‐holography at two orthogonal circular polarization states with 237 and 247 different holographic frames respectively, and grayscale meta‐nanoprinting at a linear polarization state with three different patterns. At the same time, the polarization multiplexed dynamic display scheme enables independent displays at three distinct polarization states with an extremely high frame rate (9523 frames per second). This advancement holds promise for applications in dynamic holographic display, optical encryption, virtual reality, and information storage.

Spatially Resolved Light-Induced Ferroelectric Polarization in α-In2Se3/Te Heterojunctions.

Light-induced ferroelectric polarization in 2D layered ferroelectric materials holds promise in photodetectors with multilevel current and reconfigurable capabilities. However, translating this potential into practical applications for high-density optoelectronic information storage remains challenging. In this work, an α-In2Se3/Te heterojunction design that demonstrates spatially resolved, multilevel, nonvolatile photoresponsivity is presented. Using photocurrent mapping, the spatially localized light-induced poling state (LIPS) is visualized in the junction region. This localized ferroelectric polarization induced by illumination enables the heterojunction to exhibit enhanced photoresponsivity. Unlike previous reports that observe multilevel polarization enhancement in electrical resistance, the device shows nonvolatile photoresponsivity enhancement under illumination. After polarization saturation, the photocurrent increases up to 1000 times, from 10-12 to 10-9 A under the irradiation of a 520nm laser with a power of 1.69 nW, compared to the initial state in a self-driven mode. The photodetector exhibits high detectivity of 4.6×1010 Jones, with a rise time of 27 µs and a fall time of 28 µs. Furthermore, the device's localized poling characteristics and multilevel photoresponse enable spatially multiplexed optical information storage. These results advance the understanding of LIPS in 2D ferroelectric materials, paving the way for optoelectronic information storage technologies.

Solution-processed 10 nm thick ferroelectric polymer film on a TiO2 nanolayer for flexible nonvolatile memories

Poly(vinylidene fluoride)-based ferroelectric polymers, known for their exceptional flexibility, cost-effectiveness, and ease of processing, have garnered significant attention in the field of nonvolatile data storage. However, a persistent challenge lies in their elevated driving voltage and subpar thermal stability, leading to excessive power consumption and restricted operational conditions. Herein, we propose a flexible ferroelectric random access memory (FeRAM) based on a ceramic/polymer bilayer consisting of a solution-processed ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] nanofilm on top of a TiO2 nanolayer. The polarized Fourier transform infrared spectroscopy spectra and piezoresponse force microscopy phase signals demonstrate that the surface effect of the underlying TiO2 induces a consistent dipole orientation along the out-of-plane direction in the P(VDF-TrFE) nanofilm. These aligned dipoles in the P(VDF-TrFE) can be efficiently switched by a low driving voltage of 5 V while maintaining a high thermal stability exceeding 100 °C. Furthermore, the FeRAM based on the TiO2/P(VDF-TrFE) bilayer exhibits a remarkable storage density of approximately 60 GB in.–2, coupled with exceptional flexibility, high transparency, and superior read/write durability. These outstanding performances indicate that the TiO2/P(VDF-TrFE) bilayer holds significant potential for applications in high-density information storage within flexible electronics.

Acoustic Skyrmionic Mode Coupling and Transferring in a Chain of Subwavelength Metastructures.

Skyrmions, a stable topological vectorial textures characteristic with skyrmionic number, hold promise for advanced applications in information storage and transmission. While the dynamic motion control of skyrmions has been realized with various techniques in magnetics and optics, the manipulation of acoustic skyrmion has not been done. Here, the propagation and control of acoustic skyrmion along a chain of metastructures are shown. In coupled acoustic resonators made with Archimedes spiral channel, the skyrmion hybridization is found giving rise to bonding and antibonding skyrmionic modes. Furthermore, it is experimentally observed that the skyrmionic mode of acoustic velocity field distribution can be robustly transferred covering a long distance and almost no distortion of the skyrmion textures in a chain of metastructures, even if a structure defect is introduced in the travel path. The proposed localized acoustic skyrmionic mode coupling and propagating is expected in future applications for manipulating acoustic information storage and transfer.

Ab initio investigation of the geometrical behavior in solution and electronic structure of the anion complexes [bis(1,3-dithiole-2-thione-4,5-dithiolate)M], for M = Bi(III), Sb(III), and Zn(II).

1,3-Dithiole-2-thione-4,5-dithiolate (dmit) ligands are known for their conductive and optical properties. Dmit compounds have been assessed for use in sensor devices, information storage, spintronics, and optical material applications. Associations with various metallic centers endow dmit complexes with magnetic, optical, conductive, and antioxidant properties. Optical doping can facilitate the fabrication of magnetic conductor materials from ground-state nonmagnetic cations. While most studied complexes involve transition-metal centers due to their diverse chemistry, compounds with representative elements are less explored in the literature. This study investigated the structural and electronic properties of bisdmit complexes with representative Bi(III), Sb(III), and Zn(II) cations. AIMD calculations revealed two new geometries for Bi(III) and Zn(II) complexes, diverging from the isolated geometry typically used in quantum chemical calculations. The coordination of acetonitrile molecules to the cationic centers of the complexes resulted in unstable structures, while the dimerization of the complexes was stable. SA-CASSCF/NEVPT2 calculations were applied to the structures of the isolated complexes and stable dimers, confirming the multireference character of the electronic structure of the three systems and the multiconfigurational character of the Bi(III) complex. The electronic spectra simulated by the STEOM-DLPNO-CCSD calculations accurately reproduced the experimental UV‒Vis spectra indicating the participation of the isolated Bi(III) dmit complex and its dimeric form in solution. AIMD calculations of the dmit salts were conducted using the GFN2-xTB method with 60 explicit acetonitrile molecules as the solvent at 300K for a total simulation time of 50.0ps, with printing intervals of 0.5fs. The final geometries were optimized employing the PBEh-3c compound method, incorporating implicit conductor-like polarizable continuum model (CPCM) solvation for acetonitrile. Local energy decomposition (LED) analysis at the DLPNO-CCSD(T)/Def2-TZVP level of theory was utilized to investigate the stability of the complex geometries identified by AIMD. The electronic structures of the complexes were assessed using the SA-CASSCF/NEVPT2/Def2-TZVP method to confirm the multiconfigurational and multireference nature of their electronic structures. Electronic spectra were analyzed using the STEOM-DLPNO-CCSD/Def2-TZVP method, with CPCM used to simulate an acetonitrile medium.

Structural, magnetic, magnetocaloric behavior and magneto-transport, electrical polarization study in 3d based bulk and nano-crystalline multiferroic double perovskite Dy2MnCoO6

In this paper, we report a detailed investigation of the crystal structure, magnetic, magnetocaloric, magneto-transport and electrical polarization properties of a new multiferroic material in the polycrystalline and nanocrystalline form of the Dy2MnCoO6 double perovskite. Both compounds crystallized in the monoclinic structure with P21/n space group. The magnetic properties of both systems are mainly dominant ferromagnetic (FM) and weak antiferromagnetic (AFM). The FM/AFM coupling is related by the competing and combining functions of the radius and the magnetic moments of rare earth ions (i.e. 3d–4f exchange interactions). The reduction of the saturation magnetization in the isothermal magnetization curves can be explained by the existence of anti-phase boundaries and local anti-site defects in the system. Moreover, these materials hold reasonable values of magnetocaloric parameters and the absence of hysteresis makes the system a potential candidate for magnetic refrigeration. These compounds revealed two magnetic phase transitions, according to the appearance of two peaks in the temperature dependence of magnetic entropy change curves. The temperature dependent resistivity data for both the systems display semiconductor nature near room temperature and insulating like behavior at low temperature regime. The variable-range hopping conduction mechanism is used to best understand their transport mechanism. In addition, the electrical polarization loop at low temperature confirms the presence of ferroelectricity for both the studied systems. The decreases polarization under an external magnetic field evidence the weak magnetoelectric coupling. The coexistence of FM ordering with insulating behavior and ferroelectricity at low temperature promises new opportunities and improvements in next generation applications for information storage, spintronic, and sensors.

Full-color, time-valve controllable and Janus-type long-persistent luminescence from all-inorganic halide perovskites

Long persistent luminescence (LPL) has gained considerable attention for the applications in decoration, emergency signage, information encryption and biomedicine. However, recently developed LPL materials – encompassing inorganics, organics and inorganic-organic hybrids – often display monochromatic afterglow with limited functionality. Furthermore, triplet exciton-based phosphors are prone to thermal quenching, significantly restricting their high emission efficiency. Here, we show a straightforward wet-chemistry approach for fabricating multimode LPL materials by introducing both anion (Br−) and cation (Sn2+) doping into hexagonal CsCdCl3 all-inorganic perovskites. This process involves establishing new trapping centers from [CdCl6-nBrn]4− and/or [Sn2-nCdnCl9]5− linker units, disrupting the local symmetry in the host framework. These halide perovskites demonstrate afterglow duration time ( > 2,000 s), nearly full-color coverage, high photoluminescence quantum yield ( ~ 84.47%), and the anti-thermal quenching temperature up to 377 K. Particularly, CsCdCl3:x%Br display temperature-dependent LPL and time-valve controllable time-dependent luminescence, while CsCdCl3:x%Sn exhibit forward and reverse excitation-dependent Janus-type luminescence. Combining both experimental and computational studies, this finding not only introduces a local-symmetry breaking strategy for simultaneously enhancing afterglow lifetime and efficiency, but also provides new insights into the multimode LPL materials with dynamic tunability for applications in luminescence, photonics, high-security anti-counterfeiting and information storage.

The Molecular Design and Electroluminescent Performance of Near-Infrared (NIR) Iridium(III) Complexes Bearing Isoquinoline-, Phthalazine- and Phenazine-Based Ligands.

Near-infrared (NIR) light has characteristics of invisibility to human eyes, less background interference, low light scattering, and strong cell penetration. Therefore, NIR luminescent materials have significant applications in imaging, sensing, energy, information storage and display. The development of NIR luminescent materials thus has emerged as a highly dynamic area of research in the realm of contemporary materials. To date, NIR luminescent materials are roughly divided into inorganic materials and organic materials. Compared with inorganic materials, organic NIR luminescent materials have become a hot research topic in recent years due to their rich sources, easy control of structure, simple preparation process, low cost, and good film-forming properties. Among them, iridium(III) [Ir(III)] complexes exhibit excellent properties such as thermal stability, simple synthesis, easy color modulation, short excited state lifetimes, and high brightness, thus becoming one of the ideal luminescent material systems for preparing high-quality organic light-emitting diodes. Therefore, how to obtain Ir(III) complexes with NIR emission and high efficiency through molecular design is a necessary and promising research topic. This work reviews the research progress of representative NIR Ir(III) complexes bearing isoquinoline-, phenazine-, and phthalazine-based ligands reported in recent years and introduces the design strategies and electroluminescent performances of NIR Ir(III) complexes.

Amorphous to Crystalline Phase Transformation Enables Tunable Persistent Luminescence for Multi‐Mode Optical Information Storage

AbstractMulti‐mode luminescence tuning through in situ crystallization of topological glass holds significance for photonics applications. Here, NaAlSiO4:Eu2+‐based glass ceramics are presented as stable persistent luminescence (PersL) materials by controlling the phase transformation in Eu2+ doped Na2O‐Al2O3‐SiO2 from amorphous glass to crystalline nepheline phase. X‐ray and UV excited PersL colors from blue to yellow are realized by adjusting the crystallization duration time, and trap statuses reveal the dynamic PersL process with a trap redeployment from 0.83 to 1.09 eV during the transformation. Optical information storage model is constructed with a structure of stacked emitting layers to enhance storage capacity. X‐ray excited luminescence time‐lapse imaging is further demonstrated with optical memory longer than 5 days. These findings advance the development of superior stable PersL glass ceramics and offer optical manipulation tactics for multi‐mode optical information storage applications.