Rewritable Data Storage Research Articles

Fully Optical Control of Polarization Current Direction in a Cyanide-Bridged Trinuclear Complex.

As a remote and non-contact stimulus, light offers the potential for manipulating the polarization of ferroelectric materials without physical contact. However, in current research, the non-contact write-read (erase) process lacks direct observation through the stable current as output signal. To address this limitation, we investigated the photoinduced polarization switching capabilities of the cyanide-bridged compound [Fe2Co] using visible light, leading to the achievement of rewritable polarization. By subjecting [Fe2Co] crystals to alternating irradiation with 785 nm and 532 nm light, the polarization changes exhibited a distinct square wave pattern, confirming the reliability of the writing and erasing processes. Initialization involved exposing specific crystal units to 532 nm light for storing "1" or "0" information, while reading was accomplished by scanning the units with 785 nm light, resulting in brief current pulses for "1" states and no current signal for "0" states. This research unveils new possibilities for optical storage systems, paving the way for efficient and rewritable data storage and retrieval technologies, such as the next-generation memories.

Fully Optical Control of Polarization Current Direction in a Cyanide‐Bridged Trinuclear Complex

As a remote and non‐contact stimulus, light offers the potential for manipulating the polarization of ferroelectric materials without physical contact. However, in current research, the non‐contact write‐read (erase) process lacks direct observation through the stable current as output signal. To address this limitation, we investigated the photoinduced polarization switching capabilities of the cyanide‐bridged compound [Fe2Co] using visible light, leading to the achievement of rewritable polarization. By subjecting [Fe2Co] crystals to alternating irradiation with 785 nm and 532 nm light, the polarization changes exhibited a distinct square wave pattern, confirming the reliability of the writing and erasing processes. Initialization involved exposing specific crystal units to 532 nm light for storing "1" or "0" information, while reading was accomplished by scanning the units with 785 nm light, resulting in brief current pulses for "1" states and no current signal for "0" states. This research unveils new possibilities for optical storage systems, paving the way for efficient and rewritable data storage and retrieval technologies, such as the next‐generation memories.

Multicolor emissive organic material to display aggregation caused red shift with dual state emission, and application towards rewritable data storage

The development of dual-state organic luminogens with high emission efficiency both in solution and solid phase is still a difficult task. Dual-state emissive fluorescent materials have proven to have a much broader application in several fields. Molecular design plays a significant role in fabricating switchable as well as tunable emissions. Nonetheless, the mechanism of dual-state emission needs to be studied further. Herein, two compounds, Blue-Yellow emissive material (BYEM) and Green-Red emissive material (GREM), have been designed and synthesized for a novel class of luminogens with dual-state emission (DSEgens) properties. These compounds emit luminously in solution state as well as solid state, with Aggregation Caused Red-Shifted Emission (ACRE) emission. Close-packed molecular structure and the steric hindrance effect can reduce the intramolecular rotation solution state, which accelerates the radiative transition of the compound in the solution state. On the contrary, in the solid state, the twisted structure and intermolecular C–H⋯π interactions can indorse the J-aggregation, which leads to the high fluorescence at the solid state. Significant red shift emission at solid state has been supported by theoretical calculations. On the other hand, by combining a partly shared donor–acceptor unit based on the twisted molecule, these compounds have shown good solvatochromic behavior. Gradual redshift emission has been observed as the solvent polarity is increased. These dual state highly emissive compounds can be applied in several industrial applications as well as the biomedical field.

Designing Glass and Crystalline Phases of Metal-Bis(acetamide) Networks to Promote High Optical Contrast.

Owing to their high tunability and predictable structures, metal-organic materials offer a powerful platform to study glass formation and crystallization processes and to design glasses with unique properties. Here, we report a novel series of glass-forming metal-ethylenebis(acetamide) networks that undergo reversible glass and crystallization transitions below 200 °C. The glass-transition temperatures, crystallization kinetics, and glass stability of these materials are readily tunable, either by synthetic modification or by liquid-phase blending, to form binary glasses. Pair distribution function (PDF) analysis reveals extended structural correlations in both single and binary metal-bis(acetamide) glasses and highlights the important role of metal-metal correlations during structural evolution across glass-crystal transitions. Notably, the glass and crystalline phases of a Co-ethylenebis(acetamide) binary network feature a large reflectivity contrast ratio of 4.8 that results from changes in the local coordination environment around Co centers. These results provide new insights into glass-crystal transitions in metal-organic materials and have exciting implications for optical switching, rewritable data storage, and functional glass ceramics.

Order-disorder structural transition in Pr3+-doped Ba3Ga2O6 for rewritable and write-once-read-many optical data storage

The emerging challenges of the big data era, both in storage density and security, require the development of the next-generation optical data storage materials. Here, we report for the first time a photo-stimulated luminescence (PSL) material, Ba3Ga2O6: Pr3+, for rewritable optical storage and write-once-read-many data preservation. Ba3Ga2O6: Pr3+, with an isolated deep trap depth in the range 1.26–1.53eV, has been used for data encoding/decoding under the excitation of 254 nm UV light and by the simulation of an 808 nm NIR laser. Meanwhile, the phosphor allows for high-security write-once-read-many optical memory by taking advantage of the irreversible change of the photoluminescence (PL) color from blue to green (a binary blue ‘0’ and green ‘1’ code) irradiated by 365 nm UV light. The comprehensive investigations indicate that the irreversible PL switching is as a result of the order-disorder structural transition by thermal treatment. The new persistent luminescence material not only exhibits promising applications in sustainable rewritable data storage, but also paves the way for write-once-read-many optical information storage with a high level of security.

Rewritable Macromolecular Data Storage with Automated Read‐out

AbstractRewriting data stored on synthetic macromolecules is an interesting feature, even though it is considered as being quite challenging within the area of digital macromolecules. In this context, we initially studied a strategy for modifying the position tag of sequence‐encoded macromolecules in a reversible manner. The efficiency of this method, which relies on the orthogonal cleavage of a thioester moiety via aminolysis, was demonstrated by modifying parts of an exemplary sentence. Simultaneously, a novel algorithm was developed to ease the read‐out of macromolecular information by means of MS/MS techniques. This program, Oligoreader, can identify potential information‐containing macromolecules from a series of MS1 spectra, analyze the corresponding MS2 spectra, and finally decode the data. Consequently, the algorithm simplifies the entire read‐out process by avoiding any interference from the operator, which increases the potential for blind sequencing of uniform macromolecules.

Rewritable Macromolecular Data Storage with Automated Read-out.

Rewriting data stored on synthetic macromolecules is an interesting feature, even though it is considered as being quite challenging within the area of digital macromolecules. In this context, we initially studied a strategy for modifying the position tag of sequence-encoded macromolecules in a reversible manner. The efficiency of this method, which relies on the orthogonal cleavage of a thioester moiety via aminolysis, was demonstrated by modifying parts of an exemplary sentence. Simultaneously, a novel algorithm was developed to ease the read-out of macromolecular information by means of MS/MS techniques. This program, Oligoreader, can identify potential information-containing macromolecules from a series of MS1 spectra, analyze the corresponding MS2 spectra, and finally decode the data. Consequently, the algorithm simplifies the entire read-out process by avoiding any interference from the operator, which increases the potential for blind sequencing of uniform macromolecules.

Fabrication of Ge<sub>30</sub>Te <sub>70-x</sub>Sb<sub>x</sub> Glasses Alloys and Studying the Effect of Partial Substitution on D.C Electrical Energy Parameters

The non-linear components has been emphasized for its multiple applications in rewritable recording and data storage devices. Chalcogenide glasses materials are promising due to their high refractive index. In this paper, alloys for Ge30Te70-xSbxglasses semiconductor (where x =0.0, 5, 10, 15 and 20) will be fabricated by melt quenching method. The effect of partial substitution on DC electric power parameters, and its knowledge of electrical conduction mechanisms, were investigated to determine the effect of Antimony on the density of extended states, local states, and in Fermi energy states. The electrical measurements revealed the existence of three conduction mechanisms depend on the temperature: at high temperature the conduction will be in the extended state. The local states are responsible at medium temperature, and at low temperature it will related to the Fermi level. The effect of partial substitution had produced change in all electrical conductivity parameters including the (extended, localized, and Fermi) density of states, the activation energy, tail width (ΔE), hoping transition distance (R), and interatomic distances a.

The Thinnest Light Disk: Rewritable Data Storage and Encryption on WS2 Monolayers (Adv. Funct. Mater. 36/2021)

The Thinnest Light Disk: Rewritable Data Storage and Encryption on WS₂ Monolayers (Adv. Funct. Mater. 36/2021)

The Thinnest Light Disk: Rewritable Data Storage and Encryption on WS2 Monolayers

AbstractThe thinnest light disk is demonstrated at the atomic level by developing an erasable method to directly write encrypted information onto WS2 monolayers. The write‐in is realized by precise control of photoluminescence emission by means of ozone functionalization and scanning focused laser beam. The visual decryption and reading‐out of information are enabled by fluorescence contrast. The high encryption level is ensured by the threshold power upon which the data deletion will be triggered. Owing to the high spatial resolution and power sensitivity, the storage capacity within <1 nm thickness can be up to ≈62.5 MB cm−2, and the writing speed can reach ≈6.25 MB s−1. Density functional theory calculations suggest that the disk formatting is realized by ozone molecule adsorption induced localized unoccupied states, while the read‐in relies on the passivation of defects via substitution of the sulfur vacancies with oxygen atoms. The results of this study promote data storage and encryption on the atomic scale.

Image Encoding Using Multi-Level DNA Barcodes with Nanopore Readout.

Deoxyribonucleic acid (DNA) nanostructure-based data encoding is an emerging information storage mode, offering rewritable, editable, and secure data storage. Herein, a DNA nanostructure-based storage method established on a solid-state nanopore sensing platform to save and encrypt a 2D grayscale image is proposed. DNA multi-way junctions of different sizes are attached to a double strand of DNA carriers, resulting in distinct levels of current blockades when passing through a glass nanopore with diameters around 14nm. The resulting quaternary encoding doubles the capacity relative to a classical binary system. Through toehold-mediated strand displacement reactions, the DNA nanostructures can be precisely added to and removed from the DNA carrier. By encoding the image into 16 DNA carriers using the quaternary barcodes and reading them in one simultaneous measurement, the image is successfully saved, encrypted, and recovered. Avoiding any proteins or enzymatic reactions, the authors thus realize a pure DNA storage system on a nanopore platform with increased capacity and programmability.

The inhibition of CsPbBr3 nanocrystals glass from self-crystallization with the assistance of ZnO modulation for rewritable data storage

In the era of big data, the large amount of data generated every second requires modern and advanced data storage technologies. Femtosecond (fs) laser induced crystallization allow for the realization of fixed-point crystallization inside the CsPbBr3 nanocrystals glasses (CPB), which can be applied in data storage. However, CPB is prone to self-crystallization prior to further heat treatment, interfering with fs-induced crystallization inside the glass and seriously hindering its application in data storage. Herein, we first propose the inhibition of CPB from self-crystallization by modulating the content of ZnO (4–20 mol%) using a melt-quenching method. ZnO was employed as a network modifier and was closely related to the glass network structure. When the content of ZnO was 4%, the CPB did not self-crystallize and was colorless. It was applied in the rewritable data storage by combining the 800 nm fs laser-induced crystallization, annealing (460 ℃/0.5 h) and fs laser erasing (20 mW). This work demonstrates a simple and efficient way to control the self-crystallization of CPBs, enhancing their potential practical application in high-capacity optical data storage with ultra-long working lifetimes.

Nanopore-Based DNA Hard Drives for Rewritable and Secure Data Storage.

Nanopores are powerful single-molecule tools for label-free sensing of nanoscale molecules including DNA that can be used for building designed nanostructures and performing computations. Here, DNA hard drives (DNA-HDs) are introduced based on DNA nanotechnology and nanopore sensing as a rewritable molecular memory system, allowing for storing, operating, and reading data in the changeable three-dimensional structure of DNA. Writing and erasing data are significantly improved compared to previous molecular storage systems by employing controllable attachment and removal of molecules on a long double-stranded DNA. Data reading is achieved by detecting the single molecules at the millisecond time scale using nanopores. The DNA-HD also ensures secure data storage where the data can only be read after providing the correct physical molecular keys. Our approach allows for easy-writing and easy-reading, rewritable, and secure data storage toward a promising miniature scale integration for molecular data storage and computation.

H-aggregate triggered mechanochromic luminescence property of 7-(diethylamino)-coumarin-3-carbaldehyde oxime derivative

For the organic luminogens, the packing structure and fluorescent emission of H-aggregate could be affected by mechanical stimuli. According to the finding, here a new coumarin oxime derivative 4-chloro-7-(diethylamino)-coumarin-3-carbaldehyde oxime A1 showing reversible mechanochromic luminescence (MCL) property was developed. Optical properties study in the solution and DFT calculation revealed that A1 had ICT nature. The emission wavelength in solid state of A1 changed reversibly from 515 nm to 540 nm upon mechanical stimuli and solvent treatment. To demonstrate the relationship between MCL property and molecular structure, another three relative coumarin oxime compounds were synthesized. The results showed that the formation of H-aggregate in solid state observed by X-ray diffraction analysis was considered to be responsible for MCL property of A1, and the intermolecular H-bonding caused by oxime hydroxyl group played a key role in the formation of H-aggregate. Furthermore, the potential application in rewritable data storage based on the MCL behavior of A1 was studied.

An information carrier based on turn-on type mechanochromic luminescent material: Application for rewritable binary data storage

We report a turn-on type mechanochromic luminescent (MCL) material in this work. The molecular design, including the electron donor-acceptor (D-A) pairs and single-bond rotation, endows the material with both intramolecular charge transfer (ICT) and aggregation-enhanced emission (AEE) nature. It shows remarkable emission enhancement with large blue-shift upon grinding and is able to convert back to the initial state after thermal treatment, suggesting high sensitivity and fatigue resistance. An information carrier based on mechanochromic material is developed, by which the binary data can be written by mechanical encoding and erased by heating.

Mechanoresponsive Material of AIE-Active 1,4-Dihydropyrrolo[3,2-b]pyrrole Luminophores Bearing Tetraphenylethylene Group with Rewritable Data Storage.

A new tetraphenylethylene (TPE) functionalized 1,4-dihydropyrrolo[3,2-b]pyrrole derivative (APPTPECN) was synthesized with obvious aggregation-induced emission (AIE) active by simple synthetic method. APPTPECN exhibited reversible mechanofluorochromic (MFC) behavior. The powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) investigations exhibited that the MFC nature is originated through a conversion from the microcrystalline to amorphous phase under the stimulus of external force. The results obtained would be of major help in understanding the MFC mechanism and designing new MFC materials. Compound APPTPECN has the potential possibility to employ in rewritable data storage and is of assistance in the rational design of smart luminescent materials.

Phase evolution and formation of λ phase in Ti3O5 induced by magnesium doping

λ-Ti3O5 is a promising phase-transition metal oxide for the application in rewritable data storage, heat storage and smart optoelectronic devices due to its bistable metal-semiconductor transition (MST) characteristics between λ and β phase. However, λ-Ti3O5 is a room-temperature metastable phase and it's synthesis has been a great challenge. This paper presented a magnesium (Mg)-doping strategy for phase control of Ti3O5 to obtain the λ-Ti3O5 via carbothermal reduction method. The results revealed that Mg-doping induced a crystal-structure modification in Ti3O5 by tuning the Mg-doping content. Particularly, it suggested that the phase-transition temperature (Tc) of β–λ was reduced efficiently by increasing the Mg additive amount, and the λ phase was stabilized at room temperature eventually. Electrical resistivity measurement demonstrated a remarkable decrease in resistivity of Ti3O5, indicating a β–λ–α phase evolution induced by Mg-doping. In-situ temperature-dependent XRD was also employed to confirm the phase evolution and phase-transition characteristic of Ti3O5. This work offered considerable insights into a controllable crystal-structure modification for Ti3O5 by a doping strategy and the mechanism to the stabilization of metastable λ-Ti3O5.

Error-free reconstruction of magnetic hologram via improvement of recording conditions in collinear optical system.

Magnetic holographic memory is expected as a rewritable high-capacity data storage technology. To improve the reconstructed image, we investigate recording conditions by numerical simulation and experiments. We found experimentally that four diffracted beams from a digital micromirror device interfere with each other at a suitable defocus recording point, and such overlapping is favorable to obtain clear reconstruction images without diffuser. Subsequently, we modify the shape of the reference beam to ensure more effective interference. As a result, we achieve error-free image reconstruction from the magnetic hologram. Our results indicate that magnetic holograms can potentially be utilized as holographic memory.

Rewritable ternary data storage devices based on polymethacrylate containing pendent azobenzene–naphthalene with the combined effects of conformation change and charge traps

We formed an ITO/polymer/Al device showing different memory characteristics with various alkyl lengths in the side-chains of the polymers.

A large scale perfect absorber and optical switch based on phase change material (Ge2Sb2Te5) thin film

In the conventional optical coating, the minimum thickness required to achieve anti-reflection should be quarter wavelength (λ/4n, where n is the refractive index). However, it was demonstrated that a lossy thin film with the thickness below quarter wavelength can also sustain the interference effect leading to a high absorption close to unity. In this paper we show that by depositing a phase change material Ge2Sb2Te5 (GST) thin film (amorphous) on a metal reflector, unity absorption is attainable. We attribute the high absorption to the interference effect within the GST thin film even though its thickness is less than a quarter wavelength. The wavelength of the absorption peak can be tuned by adjusting the GST film thickness. In addition, the performance of this perfect absorber is insensitive to the incidence angle variation. Relying on the fact that GST is a phase change material, the absorption band can be tuned by inducing the phase transition of GST. The huge difference of the reflectivity between amorphous and crystalline phase leads to a high optical contrast ratio as high as 400 at the specific wavelength, suggesting the potential in the application of optical switch and rewritable data storage.