Information Storage Applications Research Articles

Conjugating Coumarin with Tetraphenylethylene to Achieve Dual-State Emission for Reversible Mechanofluorochromism and Live Cell Imaging.

Dual-state emission luminogens (DSEgens) are receiving research interest in the construction of multifunctional materials due to their inherent advantage of high emission efficiency in both the molecularly dispersed solution state and the solid state. However, it remains challenging in synthesizing DSEgens via a delicate manipulation of the molecular structures. This work presents an example of bright DSEgen synthesis by tuning the molecular electronic structures and conformations. Three coumarin-tetraphenylethylene (TPE) molecules with a donor-acceptor electronic structure and highly twisting conformations have been synthesized. While compound resulting from direct conjugation of coumarin with a TPE unit shows aggregation-induced emission, compound with an N,N-diaminoethyl modification on the 7-position of coumarin and compound with a further phenyl linker between coumarin and TPE units feature strong dual-state emission. Benefiting from their strong solid emission and twisting conformations, these fluorophores display reversible mechanofluorochromism. Finally, applications for rewritable information storage in the solid state and live-cell imaging in the solution state were demonstrated.

Developing "smart windows" for optical storage and temperature sensing based on KNN transparent ceramics

Smart windows have attracted considerable attention due to their wide applications in optical data storage, switchable sunroof and temperature sensing. The development strategy for smart windows is focused on performance design, enhancement and integration. However, developing integrated multi-functional smart windows in a single material remains a challenge. In this work, we have successfully prepared (K0.5Na0.5)0.95Ba0.04Er0.01NbO3 (4Ba-1Er-KNN) transparent ceramics for potential applications of temperature detection and optical information storage in smart windows. With alternating ultraviolet (UV) illumination and 300 °C thermal stimulation, the prepared 4Ba-1Er-KNN ceramics can not only achieve non-destructive luminescence readout, but also exhibits an ultra-high photochromic (PC) contrast with rapid response time of 1 s. Furthermore, based on the up-conversion (UC) photoluminescence (PL) intensity ratio of Er3+: 2H11/2/4S3/2 thermally coupled levels, excellent low-temperature sensing performance with the maximum relative sensitivity of 0.023 K−1 at 213 K is obtained. The integration between UC PL, PC response and temperature sensing performance makes it possible to develop multi-functional smart windows.

A general phase-modulating solution for generating optical array with arbitrary dimensions via mapping space

It is of great significance to control the energy, location, topological charge, and other parameters of each beam in three-dimensional space. Thus, optical array is proposed and widely used in processing, communication, microscopy, storage, and other fields. However, the current methods to generate optical array are only effective in specific scenarios. In this work, we present an efficient and general method, which separates iterative calculation and parameter selection by introducing a special mapping space, allowing the generation of optical arrays with arbitrary dimensions, optional parameters, and any energy ratios. This method is compared with traditional methods from both simulation and experiment and is superior in diffraction efficiency, focus amount, and calculation speed. Additionally, a five-dimensional optical array with specially designed parameters is produced to show the versatility for different parameters. It shows advantages in beam shaping and parallelization and will be instrumental for applications in information storage, industrial processing, and three-dimensional imaging.

Novel optical soliton molecules formed in a fiber laser with near-zero net cavity dispersion

Soliton molecules (SMs) are stable bound states between solitons. SMs in fiber lasers are intensively investigated and embody analogies with matter molecules. Recent experimental studies on SMs formed by bright solitons, including soliton-pair, soliton-triplet or even soliton-quartet molecules, are intensive. However, study on soliton-binding states between bright and dark solitons is limited. In this work, the formation of such novel SMs in a fiber laser with near-zero group velocity dispersion (ZGVD) is reported. Physically, these SMs are formed because of the incoherent cross-phase modulation of light and constitute a new form of SMs that are conceptually analog to the multi-atom molecules in chemistry. Our research results could assist the understanding of the dynamics of large SM complexes. These findings may also motivate potential applications in large-capacity transmission and all-optical information storage.

Multi-color solid-state photoluminescence from orthogonally multi-stimuli-responsive organic molecule for advanced information storage and encryption

The smart materials displaying strong solid-state photoluminescence and unique traceable changes in response to external stimuli, are appealing for the application in information storage and encryption. However, the vast majority of previous reports rely on a single way, i.e., reversible or irreversible stimulus response to change the fluorescent emission, limiting the level of security for information storage and encryption. In this study, benzothiazole-maleimide smart organic fluorescent molecule (BTMA) were developed that could perform multiple both reversible and irreversible stimulus responses simultaneously. In addition to the diversity, these responses were interconnected but orthogonal that can be organized in different ways, allowing information to be stored with different forms. By rational regulation of irreversible thiol-ene (TE) click reaction, reversible Diels-Alder (DA) addition reaction and the protonation/deprotonation, and combining with specific algorithms, labels or patterns prepared from BTMA and its derivatives successfully realized the concealment, reading, confirmation of authenticity and destruction of confidential information. The strategy of rational combination of irreversible and reversible stimulus responses, and efficiently utilizing the multi-component synergies provides a new idea for designing intelligent new materials for advanced information storage and encryption.

Photonic Pseudospin Skyrmion in Momentum Space

Magnetic Skyrmions are topologically protected spin structures with sophisticated swirls of electron spins. In recent times, photonic counterparts of the magnetic Skyrmions have been discovered with new deep-subwavelength characteristics promising for future applications in optical information storage and transfer. While the photonic Skyrmions in real space have been observed in diverse photonic systems, studies on the photonic Skyrmions in momentum space have rarely been done. Here we show different forms of pseudospin Skyrmion around the Dirac point in momentum space of photonic crystals with the Kagome and honeycomb lattice. The pseudospin Skyrmions in momentum space are directly related to the topologically nontrivial states and manipulated by the inter-cell and intra-cell interactions between cylinders of the photonic crystal. The observation of the pseudospin Skyrmion in momentum space is expected to be valuable for manipulation of the flows and polarizations of light in topologically robust ways.

The Relationship between Electron Transport and Microstructure in Ge2Sb2Te5 Alloy.

Phase-change random-access memory (PCRAM) holds great promise for next-generation information storage applications. As a mature phase change material, Ge2Sb2Te5 alloy (GST) relies on the distinct electrical properties of different states to achieve information storage, but there are relatively few studies on the relationship between electron transport and microstructure. In this work, we found that the first resistance dropping in GST film is related to the increase of carrier concentration, in which the atomic bonding environment changes substantially during the crystallization process. The second resistance dropping is related to the increase of carrier mobility. Besides, during the cubic to the hexagonal phase transition, the nanograins grow significantly from ~50 nm to ~300 nm, which reduces the carrier scattering effect. Our study lays the foundation for precisely controlling the storage states of GST-based PCRAM devices.

X-Ray Triggered Coordination-Bond Breakage in Dysprosium-Organic Framework and its Impact on Magnetic Properties.

Photosensitive lanthanide-based single-molecule magnets (Ln-SMM) are very attractive for their potential applications in information storage, switching, and sensors. However, the light-driven structural transformation in Ln-SMMs hardly changes the coordination number of the lanthanide ion. Herein, for the first time it is reported that X-ray (λ=0.71073 Å) irradiation can break the coordination bond of Dy-OH2 in the three-dimensional (3D) metal-organic framework Dy2 (amp2 H2 )3 (H2 O)6 ⋅ 4H2 O (MDAF-5), in which the {Dy2 (OPO)2 } dimers are cross-linked by dianthracene-phosphonate ligands. The structural transformation proceeds in a single-crystal-to-single-crystal (SC-SC) fashion, forming the new phase Dy2 (amp2 H2 )3 (H2 O)4 ⋅ 4H2 O (MDAF-5-X). The phase transition is accompanied by a significant change in magnetic properties due to the alteration in coordination geometry of the DyIII ion from a distorted pentagonal bipyramid in MDAF-5 to a distorted octahedron in MDAF-5-X.

Rich topological spin textures in single-phase and core-shell magnetic nanodisks

Magnetic skyrmions have potential applications in future high-density information storage devices due to their small size, topologically protected structure, and ultralow energy consumption. Here, we use a variational method to study rich topological spin textures in magnetic nanodisks, including skyrmions and skyrmionlike objects. The existence of skyrmions and $k\ensuremath{\pi}$-skyrmions in a single-phase nanodisk and a disk with a core-shell structure is investigated theoretically, where the phase diagrams of possible spin states are obtained for various Dzyaloshinskii-Moriya interaction (DMI) constants and disk dimeters. Our calculations suggest that skyrmions can be generated spontaneously in a core-shell nanodisk. We also study the transitions of spin textures in the nanodisk induced by spin currents. This paper may provide guidelines for experimental realization of different topological spin textures in nanodisks with certain DMIs. The simple two-dimensional analytical method used in this paper can be used to study the magnetic phase diagrams of thin films with interface-induced DMIs.

Enhanced ferroelectric and ferrimagnetism properties at room temperature in BaTiO3 doped GaFeO3 ceramics

BaTiO3 doped GaFeO3 multiferroic ceramics were prepared by solid state sintering. The influence of BaTiO3 doping on the ferroelectric, ferrimagnetic and dielectric properties of GaFeO3 ceramics was systematically studied. The results show that 0.9GaFeO3-0.1BaTiO3 ceramics exhibit enhanced multiferroic behaviors compared with pure GaFeO3 ceramics. The residual polarization of 0.9GaFeO3-0.1BaTiO3 sample is increased from 0.05 μC/cm2 to 0.14 μC/cm2. The increase of magnetic transition temperature and remanent magnetization is attributed to the formation of BaFe12O19 phase. Our results show that 0.9GaFeO3-0.1BaTiO3 ceramics have potential applications in information storage and provide new possibilities for magnetoelectric applications.

Hydrazone‐Based AIEgens with Photofluorochromic Ability for Rewritable, Intensity‐Variable, and High‐Resolution Photopattern

AbstractPhotoswitches with multiple fluorescence states known as photofluorochromism upon photo‐induced isomerization show practical applications in information storage, anticounterfeiting, and sensors. However, it is still challenging to realize rapid isomerization, efficient fluorescence, and gradient signal output simultaneously. Herein, by incorporating luminogenic units with aggregation‐induced emission (AIE) features into photo‐responsive hydrazone, a series of novel photofluorochromic AIE compounds are developed. These newly designed compounds exhibit quantum yields of up to 38.4% and could undergo reversible and swift photo‐isomerization upon 450/365 nm irradiation. Accordingly, the fabricated photopatterns based on them are utilized as quantitatively described images for information storage, which show excellent rewritability and intensity‐variable fluorescence with a high resolution of 10 µm. This work provides a new strategy to develop intelligent photopattern systems with continuous gradient fluorescence for information storage and cybernetics.

Multi-stimuli responsiveness of pyrimidine bishydrazone: AIE, tuneable luminescence, white light emission, mechanochromism, acidochromism and its anticounterfeiting applications

The development of multifunctional properties associated with a single molecule being a centre of attention in the material science research area has been more focused in recent days. An aggregation-induced emissive (AIE) molecule having various aspects of stimuli-responsiveness such as mechanochromism, and acidochromism, along with white-light emitting behavior within a molecule will give rise to enormous applications in near future. A simple strategy to fabricate white-light emitting material from a single component system is beneficial for applications in the field of flat-panel displays and other optoelectronic devices. Herein, we have designed a D-A-D triad-based AIE active organic molecule HYPY-DESALvia a facile one-step Schiff-base condensation reaction between 4,6-dihydrazinopyrimidine (HYPY) and 4-(N,N-diethylamino)salicylaldehyde (DESAL) containing ESIPT as well as ICT properties. This AIE-active molecule exhibits white light emission (fw ≈ 49%) feature in addition to the tunable emission characteristics in its aggregated states which can be utilized for various light emitting diode applications. The compound revealed exceptional solid-state stimuli responsiveness such as mechanofluorochromism and acidochromism. HYPY-DESAL exhibited acidochromic features with a remarkable red shift in emission wavelength greater than 150 nm in the solid state. The specific site of protonation upon TFA addition was confirmed via1H NMR titration as well as TD-DFT experiments. The interesting reversible switching characteristics of the compound upon exposure to TFA/TEA are successfully utilized for several coding-decoding, information storage, and anti-counterfeiting applications in paper strips as well as PMMA-based thin films. Taken together, the combined features of the newly designed and readily accessible molecule exhibiting multi-stimuli responsive features such as AIE, tuneable luminescence, white light emission, mechanochromism, acidochromism, vapor phase sensing applicability using paper strips as well as thin films is unique, if not unprecedented.

Three-Dimensional Perovskite Phase Transition Materials with Switchable Second Harmonic Generation Properties Introduced by Homochiral (1S,4S)-2,5-Diazabicyclo[2.2.1]-heptane.

Switchable second harmonic generation (SHG) materials have potential applications in information storage, signal processing, and so on because they can switch between SHG-on and SHG-off states. In this work, we designed and synthesized three organic-inorganic hybrid Rb halide three-dimensional (3D) perovskite materials [1S,4S 2,5-2.2.1-H2dabch]RbX3·0.5H2O (X = Cl, 1; Br, 2; I, 3) based on the chiral 1S,4S-2,5-diazabicyclo[2.2.1]heptane (1S,4S-2,5-2.2.1-dabch). The selection of homochiral organic cations ensures that the compounds 1∼3 crystallize in the noncentrosymmetric and chiral space group P212121, which further leads to reversible SHG responses of the three compounds. Through differential scanning calorimetry (DSC) and dielectric measurements, it revealed that the phase transition point of the compounds 1∼3 increased with RbCl, RbBr, and RbI. This is because the hydrogen interaction H···X between the inorganic framework [RbX3]n and the organic cation [1S,4S-2,5-2.2.1-H2dabch]2+ is increased with the order of I > Br > Cl. This study can provide an effective molecular design strategy for the exploration and construction of temperature-tunable SHG switching materials.

Research progress of applications of freestanding single crystal oxide thin film

Flexible electronics have aroused great interest of researchers because of their wide applications in information storage, energy harvesting and wearable device. To realize extraordinary functionalities, freestanding single crystal oxide thin film is utilized due to its super elasticity, easy-to-transfer, and outstanding ferro/electric/magnetic properties. Using the state-of-art synthesis methods, functional oxide films of various materials can be obtained in freestanding phase, which eliminates the restrictions from growth substrate and is transferable to other flexible layers. In this work, we first introduce wet etching and mechanical exfoliation methods to prepare freestanding single crystal oxide thin film, then review their applications in ferroelectric memory, piezoelectric energy harvester, dielectric energy storage, correlated oxide interface, and novel freestanding oxide structure. The recent research progress and future outlooks are finally discussed.

High charge carrier storage capacity and wide range X-rays to infrared photon sensing in LiLuGeO4:Bi3+,Ln3+ (Ln = Pr, Tb, or Dy) for anti-counterfeiting and information storage applications

This work not only reports Bi3+ and/or Ln3+ doped LiLuGeO4 storage phosphors with excellent charge carrier storage capacity for information storage, but also deepens our understanding on afterglow and storage phosphors and luminescence mechanisms.

Green Nanoparticles: A review

Recent years a nanoparticle have gained significant importance to applying by Green synthesis and has become one of the most specific methods. Green synthesis of nanoparticle is a new branch of nanotechnology. Since long time Indian have used herbal drugs because impactful and lesser side effect which is safe for human body. Over hundreds of years herbal medicines are manufactured on large scale for therapelitic adventure India is sitting on a gold mine of well recorded and traditionally like Ayurveda, Yoga, Unani, Siddha, Homeopathy, Naturopathy etc. In ayurveda medicinal plants are playing significant role since ancient time. Medicinal plant parts and plant products are very inexpensive source of Indian ayurvedic medicines. Different plants and their products are the most dapper regimentations of research and contemporary materials as nanoparticles in nanobiotechnology. This green synthesis method is alternative to chemical methods, since it is cheap, pollutant free and eco-friendly. The Nanoparticles (Nps) are generally less than 100nm. The study of objects less than 100 nms is called nanotechnology. Nanoparticles are glorious mineral materials of silver, platinum and gold. Gold, silver and platinum are well accredited as NPs and have significant application in optoelectronic, electronics, magnetic and information storage. Nps creates interest of the research due to its effect on chemical, electronics, energy, space industries and drug industries. Nanotechnology also includes to the characterization, manufacture, manipulative uses of Nanoparticles. Nanotechnology provides a new field for material science. Nanoparticles occupy importance due to its small size, chemical, physical and biological properties. Recently metal nanoparticles are in scientific news due to their diversified applications in various areas. The most importantly they are used in biomedical areas like targeted drug delivery, imaging, sensing and antimicrobial activity.

The halogen substitution strategy of inorganic skeletons triggers dielectric and band gap regulation of hybrid perovskites.

Organic-inorganic hybrid perovskites (OIHPs) with dielectric switching functions have aroused comprehensive scientific interest, benefitting from their promising applications in sensors and information storage. However, to date, most of these materials discovered thus far possess a single function and are limited in their applicability, failing to meet the requirements of diverse applications. Moreover, the discovery of these materials has been largely serendipitous. Building multifunctional OIHPs with dielectric switching and semiconductors remains a daunting task. In this context, by introducing [C7H16N]+ as cations and in combination with lead halide with semiconducting properties, two OIHPs [C7H16N]PbI3 (1) and [C7H16N]PbBr3 (2) ([C7H16N]+ = (cyclopropylmethyl) trimethylammonium) have been successfully designed. They have dielectric switching properties close to 253 and 279 K and semiconducting behavior with band gaps of 2.67 and 3.22 eV. The phase transition temperature increased by 26 K through halogen substitution. In summary, our findings in this study provide insights into the application of the halogen substitution regulation strategy and open up new possibilities for designing perovskite semiconductors with dielectric switching functionality.

Enhancement of the photoluminescence modulation ratio in highly transparent KNN-based ceramics for optical information storage

The combination of high transmittance and large switching contrast in transmittance and photoluminescence intensity make the K0.5Na0.5NbO3–xPr ceramics promising for optical information storage and optical switch applications.

Managing 3D GIS Data for Indoor Environment Using Property Graph Database

With the diversification of three-dimensional (3D) urban space data sources and data collection methods, the Open Geospatial Consortium published 3D spatial data standards in Geography Markup Language (GML). Among them, IndoorGML is a data model for expressing the topological relationship between indoor spaces with advantages in terms of semantic information storage and navigation applications. Conversion into a suitable binary file must be accomplished to use the IndoorGML documents through integration with other data. This study proposes a method of generating graph database objects from the documents of IndoorGML to promote usability and interoperability. The labeled property graph model is designed to reflect IndoorGML’s multilayered graph concept. Moreover, in the proposed graph model, the geometry of physical indoor spaces is segregated into separate surfaces. All elements from IndoorGML are managed with specific labels in Neo4j, the most dominant graph database. By applying the proposed method, the graph database is constructed using the officially distributed IndoorGML documents of three buildings. The number of generated graph objects is determined to confirm whether the IndoorGML features are accurately converted into graph database objects. Furthermore, the utility of the constructed graph database is verified through two scenario-based routing tests consisting of finding the optimal room with the lowest route cost and allocating indoor spaces for patrolling to outdoor security offices through indoor and outdoor data integration. In conclusion, this study confirms that the utility of IndoorGML can be promoted using a graph database system in data integration, data queries, and pathfinding applications while preserving data topology and interoperability.

Irreversible switching of vortex core in Pac-man nanodisks induced by rotating magnetic fields

Vortex has attracted great attention recently due to its potential applications in information storage, nano-oscillators and logic devices. The control of vortex polarity is key to the devices based on vortex. In this paper, an irreversible vortex core (VC) switching in Pac-man disks has been investigated by micromagnetic simulations. The switching process is closely related to the evolution of energy densities and there is a sharp peak in the local exchange energy density when VC switching occurs. Irreversible switching of VC can be realized due to the weak interaction between reversed vortex and rotating magnetic field. In the process of VC reversal, the positive and negative magnetization regions of the gyrofield are separated. Moreover, the switching time of VC decreases monotonously with frequency under rotating magnetic fields. When one direction of the rotating magnetic field is turned off, the difference in switching time is attributed to the different motion behaviors of vortex. This work benefits the potential storage applications in vortex-based spintronic devices.