Information Storage Applications Research Articles

Visual Quantitation of Dopamine-Inspired Fluorescent Adhesion with Orthogonal Phenanthrenequinone Photochemistry.

Quantifying adhesion is crucial for understanding adhesion mechanisms and developing advanced dopamine-inspired materials and devices. However, achieving nondestructive and real-time quantitation of adhesion using optical spectra remains challenging. Here, we present a dopamine-inspired orthogonal phenanthrenequinone photochemistry strategy for the one-step adhesion and real-time visual quantitation of fluorescent spectra. This strategy utilizes phenanthrenequinone-mediated photochemistry to facilitate conjoined network formation in the adhesive through simultaneous photoclick cycloaddition and free-radical polymerization. The resulting hydrogel-like adhesive exhibits good mechanical performance, with a Young's modulus of 300 kPa, a toughness of 750 kJ m-3, and a fracture energy of 4500 J m-2. This adhesive, along with polycyclic aromatic phenanthrenequinones, shows strong adhesion (>100 kPa) and interfacial toughness thresholds (250 J m-2) on diverse surfaces─twice to triple as much as typical dopamine-contained adhesives. Importantly, such an adhesive demonstrates excellent fluorescent performance under UV irradiation, closely correlating with its adhesion strengths. Their fluorescence intensities remain constant after continuous stretching/releasing treatment and even in the dried state. Therefore, this dopamine-inspired orthogonal phenanthrenequinone photochemistry is readily available for real-time and nondestructive visual quantitation of adhesion performance under various conditions. Moreover, the adhesive precursor is chemically ultrastable for more than seven months and achieves adhesion on substrates within seconds upon blue light irradiation. As a proof-of-concept, we leverage the rapid and visual quantitation of adhesion and printability to create fluorescent patterns and structures, showcasing applications in information storage, adhesion prediction, and self-reporting properties. This general and straightforward strategy holds promise for rapidly preparing functional adhesive materials and designing high-performance wearable devices.

Relationship between photochromism and persistent luminescence in barium-magnesium silicates

Photochromism and persistent luminescence (PersL) are two fascinating light-responsive effects in phosphors, both of which have found widespread applications in optical switching, optical anticounterfeiting and information storage. However, the relationship between photochromism and PersL has not been clarified, thus greatly limiting the use and design of the light-responsive materials in multifunctional applications. Herein, taking BaMgSiO4:Eu2+, TM (TM = transition metal: Fe, Co and Cr) as model materials, we first reveal that photochromism and PersL could be two independent photophysical effects, although they are both related to the charge carrier trapping/detrapping processes. Notably, photochromism and PersL show have different responses to light wavelengths, and the depth of traps involved in the two effects is also quite different. Moreover, by codoping different transition metal elements, we obtain the largest reflectance difference of ∼71 % among inorganic photochromic materials reported thus far, and demonstrate interesting multicolor photochromism, including magenta, golden and pink. Based on their distinct response to light and temperature, a multi-functionalized optical anticounterfeiting technology is proposed, which may open up a new avenue for applying the light-responsive materials in flexible electronics and wearable devices.

Tunable effect on persistent luminescence via lithium-to-niobium ratio in LiNbO3: Pr polycrystals

This study has demonstrated that lithium niobate doped with praseodymium (LiNbO3:Pr), which initially did not exhibit persistent luminescence(PersL), can display significant PersL performance through the modulation of the lithium-to-niobium ratio (RLN). By adjusting the RLN to 1, LiNbO3:Pr achieved enhanced PersL, lasting several minutes, with the afterglow's duration further influenced by the RLN. Thermoluminescence (TL) assays and energy diagram analyses have elucidated that the presence and depth of oxygen vacancy defects are critical for both the emergence and longevity of PersL LiNbO3:Pr polycrystals. These insights enhance the understanding of PersL mechanisms in lithium niobate crystals and highlight their potential for application in optical information storage.

Magnetic energy product and hysteresis behavior of antiperovskite Mn3AlN: Monte Carlo Simulation

In this study, we investigated the magnetic properties, magnetocaloric effect, magnetic energy product, and hysteresis behavior of Mn3AlN antiperovskite using Monte Carlo (MC) simulation techniques. We examined the effect of magnetic field on magnetic behavior. As the magnetic field values h increase, the amplitudes of both the specific heat peaks and the susceptibility also increase. For various external magnetic fields and temperatures, we obtained the adiabatic temperature change and the magnetic entropy change. The compound displayed a direct magnetocaloric effect. Furthermore, the relative cooling power (RCP) values for a magnetic field strength of 60 kOe are 117.54 J/kg. The hysteresis loops were used to calculate the energy product BH. These findings suggest that our material is an excellent fit for magnetic refrigeration and information storage applications.

Resistive Memristors Using Robust Electropolymerized Porous Organic Polymer Films as Switchable Materials.

Porous organic polymers (POPs) with inherent porosity, tunable pore environment, and semiconductive property are ideally suitable for application in various advanced semiconductor-related devices. However, owing to the lack of processability, POPs are usually prepared in powder forms, which limits their application in advanced devices. Herein, we demonstrate an example of information storage application of POPs with film form prepared by an electrochemical method. The growth process of the electropolymerized films in accordance with the Volmer-Weber model was proposed by observation of atomic force microscopy. Given the mechanism of the electron transfer system, we verified and mainly emphasized the importance of porosity and interfacial properties of porous polymer films for memristor. As expected, the as-fabricated memristors exhibit good performance on low turn-on voltage (0.65 ± 0.10 V), reliable data storage, and high on/off current ratio (104). This work offers inspiration for applying POPs in the form of electropolymerized films in various advanced semiconductor-related devices.

Ultra-high ON/OFF ratio with low set voltage for a Pt-Nb2O5-Pt resistivity switching device

The limited ON/OFF ratio constrains the quantity of available resistance states and the multi-level storage capability, a high ON/OFF ratio (>103) is essential for implementing multi-level storage in a resistive device. Through annealing processes for Nb2O5 films prepared by magnetron sputtering, we successfully achieved an ultra-high ON/OFF ratio of 106 and a four-order higher resistance compared to conventional binary oxide resistive random-access memory. Results confirm that annealing can effectively modulate the content of oxygen vacancies within the resistance-switching layer and the formation path of oxygen vacancies. At the same time, we observed a gradual decrease in the set voltage of the device with increasing annealing temperature, which is beneficial for the low power consumption characteristics. Therefore, appropriate annealing is a novel and effective approach to optimize device performances for better information storage applications, and its core mechanism is to modulate the concentration of Vo for constructing fixed conductive paths.

Pure-high-even-order dispersion bound solitons complexes in ultra-fast fiber lasers

Temporal solitons have been the focus of much research due to their fascinating physical properties. These solitons can form bound states, which are fundamentally crucial modes in fiber laser and present striking analogies with their matter molecules counterparts, which means they have potential applications in large-capacity transmission and all-optical information storage. Although traditionally, second-order dispersion has been the dominant dispersion for conventional solitons, recent experimental and theoretical research has shown that pure-high-even-order dispersion (PHEOD) solitons with energy-width scaling can arise from the interaction of arbitrary negative-even-order dispersion and Kerr nonlinearity. Despite these advancements, research on the bound states of PHEOD solitons is currently non-existent. In this study, we obtained PHEOD bound solitons in a fiber laser using an intra-cavity spectral pulse shaper for high-order dispersion management. Specifically, we experimentally demonstrate the existence of PHEOD solitons and PHEOD bound solitons with pure-quartic, -sextic, -octic, and -decic dispersion. Numerical simulations corroborate these experimental observations. Furthermore, vibrating phase PHEOD bound soliton pairs, sliding phase PHEOD bound soliton pairs, and hybrid phase PHEOD bound tri-soliton are discovered and characterized. These results broaden the fundamental understanding of solitons and show the universality of multi-soliton patterns.

Multi-Level Switching of Spin-Torque Ferromagnetic Resonance in 2D Magnetite.

2D magnetic materials hold substantial promise in information storage and neuromorphic device applications. However, achieving a 2D material with high Curie temperature (TC), environmental stability, and multi-level magnetic states remains a challenge. This is particularly relevant for spintronic devices, which require multi-level resistance states to enhance memory density and fulfil low power consumption and multi-functionality. Here, the synthesis of 2D non-layered triangular and hexagonal magnetite (Fe3O4) nanosheets are proposed with high TC and environmental stability, and demonstrate that the ultrathin triangular nanosheets show broad antiphase boundaries (bAPBs) and sharp antiphase boundaries (sAPBs), which induce multiple spin precession modes and multi-level resistance. Conversely, the hexagonal nanosheets display slip bands with sAPBs associated with pinning effects, resulting in magnetic-field-driven spin texture reversal reminiscent of "0" and "1" switching signals. In support of the micromagnetic simulation, direct explanation is offer to the variation in multi-level resistance under a microwave field, which is ascribed to the multi-spin texture magnetization structure and the randomly distributed APBs within the material. These novel 2D magnetite nanosheets with unique spin textures and spin dynamics provide an exciting platform for constructing real multi-level storage devices catering to emerging information storage and neuromorphic computing requirements.

Visible-light-excited robust room-temperature phosphorescence of dimeric single-component luminophores in the amorphous state

Organic room temperature phosphorescence (RTP) has significant potential in various applications of information storage, anti-counterfeiting, and bio-imaging. However, achieving robust organic RTP emission of the single-component system is challenging to overcome the restriction of the crystalline state or other rigid environments with cautious treatment. Herein, we report a single-component system with robust persistent RTP emission in various aggregated forms, such as crystal, fine powder, and even amorphous states. Our experimental data reveal that the vigorous RTP emissions rely on their tight dimers based on strong and large-overlap π-π interactions between polycyclic aromatic hydrocarbon (PAH) groups. The dimer structure can offer not only excitons in low energy levels for visible-light excited red long-lived RTP but also suppression of the nonradiative decays even in an amorphous state for good resistance of RTP to heat (up to 70 °C) or water. Furthermore, we demonstrate the water-dispersible nanoparticle with persistent RTP over 600 nm and a lifetime of 0.22 s for visible-light excited cellular and in-vivo imaging, prepared through the common microemulsion approach without overcaution for nanocrystal formation.

Modification of Polysulfide Surfaces with Low‐Power Lasers

AbstractThe modification of polymer surfaces using laser light is important for many applications in the nano‐, bio‐ and chemical sciences. Such capabilities have supported advances in biomedical devices, electronics, information storage, microfluidics, and other applications. In most cases, these modifications require high power lasers that are expensive and require specialized equipment and facilities to minimize risk of hazardous radiation. Additionally, polymer systems that can be easily modified by lasers are often complex and costly to prepare. In this report, these challenges are addressed with the discovery of low‐cost sulfur copolymers that can be rapidly modified with lasers emitting low‐power infrared and visible light. The featured copolymers are made from elemental sulfur and either cyclopentadiene or dicyclopentadiene. Using a suite of lasers with discreet wavelengths (532, 638 and 786 nm) and powers, a variety of surface modifications could be made on the polymers such as controlled swelling or etching via ablation. The facile synthesis and laser modification of these polymer systems were exploited in applications such as direct laser lithography and erasable information storage.

Modification of Polysulfide Surfaces with Low-Power Lasers.

The modification of polymer surfaces using laser light is important for many applications in the nano-, bio- and chemical sciences. Such capabilities have supported advances in biomedical devices, electronics, information storage, microfluidics, and other applications. In most cases, these modifications require high power lasers that are expensive and require specialized equipment and facilities to minimize risk of hazardous radiation. Additionally, polymer systems that can be easily modified by lasers are often complex and costly to prepare. In this report, these challenges are addressed with the discovery of low-cost sulfur copolymers that can be rapidly modified with lasers emitting low-power infrared and visible light. The featured copolymers are made from elemental sulfur and either cyclopentadiene or dicyclopentadiene. Using a suite of lasers with discreet wavelengths (532, 638 and 786 nm) and powers, a variety of surface modifications could be made on the polymers such as controlled swelling or etching via ablation. The facile synthesis and laser modification of these polymer systems were exploited in applications such as direct laser lithography and erasable information storage.

Gas-Liquid Interface Route to Hybrid Copper Bromine Perovskite Single-Crystal Membrane with Dielectric Transitions and Ferromagnetic Exchanges.

Single-crystal membranes (SCMs) show great promise in the fields of sensors, light-emitting diodes, and photodetection. However, the growth of a large-area single-crystal membranes is challenging. We report a new organic-inorganic SCMs [HCMA]2CuBr4 (HCMA = cyclohexanemethylamine) crystallized at the gas-liquid interface. It also has low-temperature ferromagnetic order, high-temperature dielectric anomalies, and narrow band gap indirect semiconductor properties. Specifically, the reversible phase transition of the compound occurs at 350/341 K on cooling/heating and exhibits dielectric anomalies and stable switching performance near the phase transition temperature. The ferromagnetic exchange interaction in the inorganic octahedra and the organic layer enables ferromagnetic ordering at low-temperature 10 K. Finally, the single crystal exhibits an indirect semiconducting property with a narrow band gap of 0.99 eV. Such rich multichannel physical properties make it a potential application in photodetection, information storage and sensors.

Self‐Recoverable, Highly Repeatable, and Thermally Stable Mechanoluminescence for Dual‐Mode Information Storage and Photonic Skin Applications

AbstractMechanically driven light generation is an intriguing phenomenon holding great promise in various fields. However, the existing mechanoluminescence (ML) materials always suffer from poor self‐recoverability, low repeatability, and environmental disturbance, severely hindering their practical applications. In this work, a self‐activating ML system based on interfacial triboelectrification is created by compositing the Ca6BaP4O17:0.02Ce3+ powders into a flexible polydimethylsiloxane (PDMS) matrix. With no need for pre‐irradiation, the composite film emits self‐activating and self‐charging ML simultaneously in response to the rubbing or stretching stimuli. Accordingly, the Ca6BaP4O17:0.02Ce3+/PDMS exhibits desirable self‐recovery and repeatable ML performance, which could still be recorded (or observed by naked eyes) even after ca. 1000 stretching cycles with a fast self‐recovery period of < 0.1 s. Furthermore, the Ca6BaP4O17:0.02Ce3+/PDMS possesses good thermal stability in a temperature range from 298 to 473 K. The developed Ca6BaP4O17:0.02Ce3+/PDMS is applicable to various fields, and the dual‐mode information storage and photonic skin devices are created as representatives. Compared to the existing oxide‐based ML materials (the ML signal disappears after only several or tens of rapid mechanics cycles), this work breaks through the bottleneck issues on the self‐recoverability, repeatability, and thermal stability, which significantly advances the ML field.

Designing Photochromic Materials La2MgSnO6:Er,Fe with Dynamic Luminescence Modulation for Dual‐mode Optical Information Reading

AbstractInorganic photochromic luminescent materials hold immense promise as potential candidates for optical information storage applications. Unfortunately, static and single reading mode of photochromic luminescent materials in bright and dark environments pose a security threat to the stored information. Here, a novel material La2MgSnO6:Er3+,Fe3+ is developed, possessing both reversible photochromic and adjustable upconversion/downconversion photoluminescent (PL) properties. Upon exposure to 275 nm ultraviolet (UV) light, the sample changes in color from white to brown. And this transformation rapidly reverses when exposed to 365 nm UV light, resulting in a corresponding alteration in luminescence intensity. Notably, when combined with photochromic, the 980 nm excited upconversion PL maintains stable luminescence, while the 365 nm excited downconversion PL exhibits significant intensity changes. Inspired by this unique feature, a dark‐field selective dual‐mode reading is proposed that depends on the excitation wavelength, including static decrypt in long‐time cases and dynamic reading in time‐limited situations. These findings have the potential to revolutionize high‐security data storage applications and drive advancements in the field.

Wavelength-multiplexed meta-image displays with Malus-assisted metasurface

A wavelength-multiplexed metasurface for four-channel display is proposed in this paper benefiting from the orientation degeneracy implied in Malus’s law. We construct the meta-atom by placing two nanorods with different sizes on a substrate, which can achieve amplitude manipulation at different wavelengths. The wavelength-multiplexed metasurface composed of these meta-atoms can display four independent binary grayscale images at different wavelengths in the reflection space. Numerical simulations validate the proposed wavelength-multiplexed metasurface with the ability to record and project four independent binary grayscale images at two wavelengths. With the advantages of high capacity, the proposed wavelength-multiplexed display metasurface will pave a way for multi-channel applications in nano-display, information storage, optical anticounterfeiting, and other relevant fields.

Highly Efficient Room-Temperature Nonvolatile Magnetic Switching by Current in Fe3GaTe2 Thin Flakes.

Effectively tuning magnetic state by using current is essential for novel spintronic devices. Magnetic van der Waals (vdW) materials have shown superior properties for the applications of magnetic information storage based on the efficient spin torque effect. However, for most of known vdW ferromagnets, the ferromagnetic transition temperatures lower than room temperature strongly impede their applications and the room-temperature vdW spintronic device with low energy consumption is still a long-sought goal. Here, the highly efficient room-temperature nonvolatile magnetic switching is realized by current in a single-material device based on vdW ferromagnet Fe3GaTe2. Moreover, the switching current density and power dissipation are about 300 and 60000 times smaller than conventional spin-orbit-torque devices of magnet/heavy-metal heterostructures. These findings make an important progress on the applications of magnetic vdW materials in the fields of spintronics and magnetic informationstorage.

Epitaxial Strain Enhanced Ferroelectric Polarization toward a Giant Tunneling Electroresistance.

A substantial ferroelectric polarization is the key for designing high-performance ferroelectric nonvolatile memories. As a promising candidate system, the BaTiO3/La0.67Sr0.33MnO3 (BTO/LSMO) ferroelectric/ferromagnetic heterostructure has attracted a lot of attention thanks to the merits of high Curie temperature, large spin polarization, and low ferroelectric coercivity. Nevertheless, the BTO/LSMO heterostructure suffers from a moderate FE polarization, primarily due to the quick film-thickness-driven strain relaxation. In response to this challenge, we propose an approach for enhancing the FE properties of BTO films by using a Sr3Al2O6 (SAO) buffering layer to mitigate the interfacial strain relaxation. The continuously tunable strain allows us to illustrate the linear dependence of polarization on epitaxial strain with a large strain-sensitive coefficient of ∼27 μC/cm2 per percent strain. This results in a giant polarization of ∼80 μC/cm2 on the BTO/LSMO interface. Leveraging this large polarization, we achieved a giant tunneling electroresistance (TER) of ∼105 in SAO-buffered Pt/BTO/LSMO ferroelectric tunnel junctions (FTJs). Our research uncovers the fundamental interplay between strain, polarization magnitude, and device performance, such as on/off ratio, thereby advancing the potential of FTJs for next-generation information storage applications.

Mechanical Rippling for Diverse Ferroelectric Topologies in Otherwise Nonferroelectric SrTiO_{3} Nanofilms.

Polar topological structures such as skyrmions and merons have become an emerging research field due to their rich functionalities and promising applications in information storage. Up to now, the obtained polar topological structures are restricted to a few limited ferroelectrics with complex heterostructures, limiting their large-scale practical applications. Here, we circumvent this limitation by utilizing a nanoscale ripple-generated flexoelectric field as a universal means to create rich polar topological configurations in nonpolar nanofilms in a controllable fashion. Our extensive phase-field simulations show that a rippled SrTiO_{3} nanofilm with a single bulge activates polarizations that are stabilized in meron configurations, which further undergo topological transitions to Néel-type and Bloch-type skyrmions upon varying the geometries. The formation of these topologies originates from the curvature-dependent flexoelectric field, which extends beyond the common mechanism of geometric confinement that requires harsh energy conditions and strict temperature ranges. We further demonstrate that the rippled nanofilm with three-dimensional ripple patterns can accommodate other unreported modulated phases of ferroelectric topologies, which provide ferroelectric analogs to the complex spin topologies in magnets. The present study not only unveils the intriguing nanoscale electromechanical properties but also opens exciting opportunities to design various functional topological phenomena in flexible materials.

Localized Temperature Engineering Enables Writing of Heterostructures in Glass for Polarized Photoluminescence of Perovskites.

Metal halide perovskite (MHP) structures that exhibit polarized photoluminescence (PL) have attracted significant interest in fabricating light field regulation elements for display, imaging, and information storage applications. We report a three-dimensional direct lithography of heterostructures for controllable polarized PL inside glass by laser-induced localized temperature engineering. The heterostructures consisted of oriented periodic structures (OPSs) and MHP nanocrystals, and the mechanism for hierarchical distribution of heterostructures was illustrated. The patterning of heterostructures for manipulable polarized PL can be used for information encryption, wave-plate, and polarized micro-LEDs.

Enhanced electromechanical coupling in Pb(ZrTi)O3 piezoelectric composite via poly(vinylidene fluoride‐trifluoroethylene) clamping

AbstractThis study presents an advanced two‐step hot‐pressing process for fabricating the 1‐3 type Pb(ZrTi)O3/poly(vinylidene fluoride‐trifluoroethylene) (PZT/P(VDF‐TrFE)) piezoelectric composite sheets, demonstrating significant potential for nondestructive evaluation and information storage applications. The engineered columnar architecture within these composites induces a two‐phase clamping effect, which, upon polarization, facilitates the elongation of PZT and suppresses its lateral vibrations, thus enhancing the electromechanical coupling effect as verified by COMSOL simulations. A notable dielectric constant of 2200 at 100 Hz and a coupling coefficient of 0.725 was achieved with specific geometric modifications to the PZT/P(VDF‐TrFE) sheets. These findings suggest that P(VDF‐TrFE) as a polymer matrix exceeds the performance of conventional epoxy matrices, offering a novel approach to designing 1‐3 type piezoelectric composites.Highlights P(VDF‐TrFE) effectively drives the elongation strain of internal PZT columns. COMSOL simulation clarifies the clamping effect of piezoelectric P(VDF‐TrFE). PZT/P(VDF‐TrFE) shows a higher kt of 0.725 than that of pure PZT samples.