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Ceramic capacitors have received great attention for use in pulse power systems owing to their ultra-fast charge–discharge rate, good temperature stability, and excellent fatigue resistance. However, the low energy storage density and low breakdown strength (BDS) of ceramic capacitors limit the practical applications of energy storage technologies. In this work, we present a series of relaxor ferroelectric ceramics (1−x) [0.94 Bi0.5Na0.5TiO3 –0.06BaTiO3]– x Sr0.7Bi0.2TiO3 (1-x BNT-BT- x SBT; x = 0, 0.20, 0.225, 0.25, 0.275 and 0.30) with improved energy storage performances by combining relaxor and antiferroelectric properties. XRD, Raman spectra, and SEM characterizations of BNT-BT-SBT ceramics revealed a rhombohedral–tetragonal phase, highly dynamic polar nanoregions, and a reduction in grain size with a homogeneous and dense microstructure, respectively. A high dielectric constant of 1654 at 1 kHz and low remnant polarization of 1.39 µC/cm2 were obtained with the addition of SBT for x = 0.275; these are beneficial for improving energy storage performance. The diffuse phase transition of these ceramics displays relaxor behavior, which is improved with SBT and confirmed by modified the Curie–Weiss law. The combining relaxor and antiferroelectric properties with fine grain size by the incorporation of SBT enables an enhanced maximum polarization of a minimized P-E loop, leading to an improved BDS. As a result, a high recoverable energy density Wrec of 1.02 J/cm3 and a high energy efficiency η of 75.98% at 89 kV/cm were achieved for an optimum composition of 0.725 [0.94BNT-0.06BT]-0.275 SBT. These results demonstrate that BNT-based relaxor ferroelectric ceramics are good candidates for next-generation ceramic capacitors and offer a potential strategy for exploiting novel high-performance ceramic materials. [ABSTRACT FROM AUTHOR]

Highlights: This review paper provides a comprehensive analysis of light–material interaction (LMI) parameters, offering insights into their significance in material processing. It examines a wide array of photothermal and photochemical processes, showcasing their versatility in creating advanced materials for energy conversion and storage applications. The review presents a multidisciplinary approach to advancing LMI technologies and highlights their potential contribution to the commercialization of future energy conversion and storage systems. This review provides a comprehensive overview of the progress in light–material interactions (LMIs), focusing on lasers and flash lights for energy conversion and storage applications. We discuss intricate LMI parameters such as light sources, interaction time, and fluence to elucidate their importance in material processing. In addition, this study covers various light-induced photothermal and photochemical processes ranging from melting, crystallization, and ablation to doping and synthesis, which are essential for developing energy materials and devices. Finally, we present extensive energy conversion and storage applications demonstrated by LMI technologies, including energy harvesters, sensors, capacitors, and batteries. Despite the several challenges associated with LMIs, such as complex mechanisms, and high-degrees of freedom, we believe that substantial contributions and potential for the commercialization of future energy systems can be achieved by advancing optical technologies through comprehensive academic research and multidisciplinary collaborations. [ABSTRACT FROM AUTHOR]

This work reports the fabrication of a large‐sized hydrogel sheet with enhanced mechanical and adhesive properties. The fabrication involves the introduction of carboxymethyl‐modified cellulose nanofibers (m‐CNFs) and solid silica nanoparticles (SSNs) as physical cross‐linkers into acrylic acid monomer (AA), followed by bar coating and photopolymerization. The addition of the nanomaterials to the monomer solution renders it viscous, enabling the fabrication of A4‐sized hydrogel sheets with uniform thickness and enhanced mechanical and adhesive properties. Interestingly, the combined incorporation of both the nanomaterials generates a synergistic effect to improve the properties much more, which results from the hierarchical rupture of the multiple hydrogen‐bonded interactions among the poly(acrylic acid) (PAA) matrix, m‐CNFs, and SSNs. Under optimal conditions, the hydrogel sheet incorporated with the dual crosslinkers exhibits a sevenfold higher toughness and a sixfold increased peel strength than plain PAA, together with good biocompatibility. Furthermore, when mesoporous silica nanoparticles (MSNs) with active agent loading into their pores are incorporated instead of SSNs, the active agent can be released from the hydrogel sheet in a sustained or temperature‐sensitive manner, indicating that the system is potentially applicable to transdermal drug delivery system with no additional adhesive. [ABSTRACT FROM AUTHOR]

In this study, Pb(Mg1/3Nb2/3)O3–Pb(Zr,Ti)O3 (PMN-PZT) single crystals were doped with hardener Mn at variable concentrations to fabricate a high-output magneto-mechano-electric (MME) generator. The dielectric constant and dielectric loss (tan δ) of the PMN-PZT crystal were gradually decreased by doping with 0 to 0.8 mol% hardener Mn acceptor. Owing to the low energy loss and enhanced energy conversion properties of the Mn-doped hard-type PMN-PZT, the MME generator achieved an improved magnetoelectric coefficient of 783.09 V per cm·Oe, and the corresponding mechanical quality factor was 315 at 0.8 mol% Mn under resonance frequency operation conditions. The Mn-modified MME device can generate a root mean square output power of 3.3 mW when an alternating current magnetic field of 8 Oe is applied, which is ∼1.8 times higher than that of the MME generator fabricated without Mn-doping. Finally, the electric power of the hard-type PMN-PZT MME generator was directly utilized to produce a self-powered light dimming system composed of an MME harvester, an energy conversion circuit, a CdS ambient light sensor, and a light-emitting diode. [ABSTRACT FROM AUTHOR]

A magneto‐mechano‐electric (MME) generator with root mean square (RMS) output exceeding 50 mW is demonstrated by integration of a piezoelectric Pb(Mg1/3Nb2/3)O3‐Pb(Zr,Ti)O3 (PMN‐PZT) single crystal and an electromagnetic induction structure to convert a gentle alternating current magnetic field into electricity to operate a high‐power consumption multi‐functional Internet of Things (IoT) environmental monitoring system. The 2nd resonance bending mode at the cantilever‐type hybrid MME generator enabled much higher output power than the conventional 1st resonance mode, which is theoretically investigated by a finite element analysis. The hybridized MME generator can generate a total RMS output power of 60 mW since the output power of the piezoelectric and electromagnetic induction parts is 26.7 and 33.3 mW, respectively, by a magnetic field of 7 Oe at the 2nd harmonic bending mode. The hybrid MME generator is employed to irradiate a red laser as well as to fully charge a commercial 280 mAh LiFePO4 battery. Finally, a self‐powered multi‐functional IoT environment monitoring system is constructed by integrating the hybrid MME generator, a power management circuit, and a wireless multiple sensing modules. The remarkable output power from the hybridized MME generator enabled the continuous sensing of nine types of ambient information and subsequent transmission of the measured data to a smartphone. [ABSTRACT FROM AUTHOR]

As a new class of two-dimensional materials, two-dimensional (2D) heterostructures constructed from metal chalcogenides (MCs) have been gaining tremendous attention due to their unprecedented physical and chemical phenomena, mainly originated from their distinct structural features such as composition, architecture type, spatial arrangement of each component, crystal structure, exposed facet and interface, dimensionality in their heterostructures. Towards the realization of practical applications, synthetic approaches need a rational design with a variety of architecture types including laterally-combined, vertically-aligned, and conformally-coated 2D MC heterostructures. Among various synthetic routes, solution-based synthesis is thought of as an alternative to fabrication through high-cost setups since it can control those structural features in a cheap fashion. This review presents recent progress on solution-based synthesis to produce various 2D MC heterostructures with a focus on the synthetic fundamentals in terms of thermodynamic and kinetic aspects related to the growth mechanism. Four different synthetic approaches are reviewed: seeded growth, cation exchange reaction, colloidal atomic layer deposition, direct synthesis including one-step process and modified electrochemical method. We also provide some representative applications of 2D MC heterostructures and their hybrid composites in various fields including optoelectronics, thermoelectrics, catalysis, and battery. Finally, we offer an insight into challenges and future directions in a synthetic improvement of 2D MC heterostructures. [ABSTRACT FROM AUTHOR]

In this study, we successfully conducted a series of computationally-assisted experiments, regarding the morphology control and chemical transformation of Te nanorods. The morphology of Te nanorods is controlled by introducing a minute amount of isovalent Se dopant. Density-functional theory calculations predicted the Gibbs surface free energy change due to the adsorbent Se on the major facets of Te nanorods. Encouraged by the theoretical prediction, we conducted experiments on Te nanorod growth and did find significant variation of the morphology of Te nanorods due to Se injection. Furthermore, we demonstrated the chemical transformation of the shape-controlled Te nanorods to binary thermoelectric compounds such as PbTe and Bi2Te3 without losing the tailored morphology. The transformed PbTe and Bi2Te3 have nanoscale grain boundaries as seen from the cross-section HRTEM image. We emphasize that the robust production of morphology-controlled thermoelectric nanorods can be an optimal approach to develop an advanced thermoelectric composite material, by which the multiscale phonon scattering effect can be maximized. [ABSTRACT FROM AUTHOR]

This article reviews recent advances in solution phase synthesis to generate 1-D and 2-D anisotropic metal chalcogenide (MC) nanostructures with a focus on using different growth mechanisms to control the shapes of the MCs. Four different synthetic approaches have been reviewed: naturally favoured growth due to its intrinsically anisotropic crystal structure, modified anisotropic growth by changing surface energies or utilizing organic templates, oriented attachment of small nanocrystal building blocks to form nanowires or nanosheets, and chemical transformation from existing nanostructures into new species. We discuss current understanding of the thermodynamic and kinetic aspects associated with the mechanisms of forming these anisotropic MC nanostructures. We provide examples of representative applications of anisotropic chalcogenide nanomaterials that are expected to be practically meaningful in the near future. The applications include electrodes for lithium ion batteries, photodetectors, thermoelectric devices, and solar cells. A brief review of other potential applications (oxygen reduction reaction, localized surface plasmon resonance, topological insulator, superconductor) is provided as well. This review ends with discussions on the challenges to be investigated thoroughly in the solution-based synthesis of anisotropic nanomaterials, which includes surface energy control, correcting the nucleation & growth mechanism, removal of the organic surfactant, kinetic study on the chemical transformation, scale-up of production, and eco-friendly synthesis. [ABSTRACT FROM AUTHOR]

This study demonstrates the growth of long triisopropylsilyethynyl pentacene (TIPS-PEN) nanofibrils in a thin film of a crystalline polymer, poly(ε-caprolactone) (PCL). During spin-coating, TIPS-PEN molecules are locally extracted around the PCL grain boundaries and they crystallize into [010] direction forming long nanofibrils. Molecular weight of PCL and weight fraction (α) of TIPS-PEN in PCL matrix are key factors to the growth of nanofibrils. Long high-quality TIPS-PEN nanofibrils are obtained with high-molecular-weight PCL and at the α values in the range of 0.03-0.1. The long nanofibrils are used as an active layer in a field-effect organic transistor. [ABSTRACT FROM AUTHOR]

Bi, a high atomic number element, has a high photoelectric absorption coefficient, and Se has anticancer activity. Hence, their compound chalcogenide (Bi2Se3) deserves a thorough investigation for biomedical applications. This study reveals that Bi2Se3 nanoplates (54 nm wide) protected with poly(vinylpyrollidone) (PVP) could be presumed to have low toxicity even at a high dose of 20 mg/kg in mice. This conclusion is made through studies on the biodistribution and 90-day long term in vivo clearance of the nanoplates. The liver and spleen are dominant organs for accumulation of the nanoplates, which is mainly due to RES absorption. 93% of the nanoplates are cleared after 90 days of treatment. Concentrations of Bi and Se in tumor tissue continuously increased until 72 h after intraperitoneal injection into mice. Such selective accumulation of Bi is utilized to enhance the contrast of X-ray computerized tomography (CT) images. Bi element concentrated in a tumor leads to damage on the tumor cells when exposed to gamma radiation. Growth of the tumor is significantly delayed and stopped in 16 days after the tumor is treated by radiation with Bi2Se3 nanoplates. This work clearly shows that Bi2Se3 nanoplates may be used for cancer radiation therapy and CT imaging. The nanoplates deserve further study for biological and medical applications. [ABSTRACT FROM AUTHOR]

Abstract: This study demonstrates an environment-friendly process to synthesize hollow SiO2 particles. The preparation of Cu2O@SiO2 particles via the sol–gel process is presented for the first time. Silica coating on the Cu2O particles has been considered not possible due to the easy etching of Cu2O in an NH4OH solution. We found that diluted NH4OH solution delayed the etching of the Cu2O particles in the sol–gel process and allowed thick coating of silica. The time-dependent etching of the Cu2O core in the Cu2O@SiO2 particles generated yolk/shell particles and finally produced the hollow SiO2 particles. The etched Cu solution could be recycled to produce Cu2O particles again. [Copyright &y& Elsevier]

Conductive electrodes and electric circuits that can remain active and electrically stable under large mechanical deformations are highly desirable for applications such as flexible displays, field-effect transistors, energy-related devices, smart clothing and actuators. However, high conductivity and stretchability seem to be mutually exclusive parameters. The most promising solution to this problem has been to use one-dimensional nanostructures such as carbon nanotubes and metal nanowires coated on a stretchable fabric, metal stripes with a wavy geometry, composite elastomers embedding conductive fillers and interpenetrating networks of a liquid metal and rubber. At present, the conductivity values at large strains remain too low to satisfy requirements for practical applications. Moreover, the ability to make arbitrary patterns over large areas is also desirable. Here, we introduce a conductive composite mat of silver nanoparticles and rubber fibres that allows the formation of highly stretchable circuits through a fabrication process that is compatible with any substrate and scalable for large-area applications. A silver nanoparticle precursor is absorbed in electrospun poly (styrene-block-butadiene-block-styrene) (SBS) rubber fibres and then converted into silver nanoparticles directly in the fibre mat. Percolation of the silver nanoparticles inside the fibres leads to a high bulk conductivity, which is preserved at large deformations (σ ≈ 2,200 S cm-1 at 100% strain for a 150-µm-thick mat). We design electric circuits directly on the electrospun fibre mat by nozzle printing, inkjet printing and spray printing of the precursor solution and fabricate a highly stretchable antenna, a strain sensor and a highly stretchable light-emitting diode as examples of applications. [ABSTRACT FROM AUTHOR]

Summary: Chemical transformation of existing inorganic nanostructures from one material into another represents a straightforward, versatile, and effective approach to nanomaterial synthesis. This approach has received increasing attention in recent years. As a unique feature, this apporach allows one to easily and independently control the chemical compositions, structures, and morphologies of nanostructured materials. This article reviews recent progress in this area by dividing the reactions into four catagories – formation of alloy, galvanic replacement, cation exchange, and anion exchange – according to the type of reaction involved. We discuss current understanding of the thermodynamic parameters and kinetic aspects, followed by highlights of a variety of relavant synthetic strategies and examples. We also discuss the possible contributions of this approach to the synthesis of novel nanomaterials and perspectives on their technological impacts. [ABSTRACT FROM AUTHOR]

Optogenetic neuromodulation is a promising technology for continuously caring various neurological diseases. Optogenetic modulating systems were demonstrated by several researchers, but still have critical issues of short lifetime of conventional or biocompatible batteries. Here, we present an optogenetic stimulating system by scavenging wasted magnetic field of home appliance. A flash-enhanced magneto-mechano-triboelectric nanogenerator (MMTENG) was fabricated to demonstrate optogenetic neuromodulation by operating a flexible micro-light-emitting diode (f-μLED). The output performance of MMTENG was enhanced by the flash-induced nano/microscale surface structure of the triboelectric Nylon film. The flash-stamped MMTENG effectively generated an open-circuit peak-to-peak voltage (V pp) of 870 V and a short-circuit current of 145 μA under a gentle alternating current (AC) magnetic field of 7 Oe. A maximum peak power of 8.1 mW was observed from the flash-induced harvester, which was 2.6 times higher than the non-treated device. A high-performance f-μLED with low-resistive ohmic contacts had the improvement of thermal/mechanical stability as well as power efficiency. The MMTENG generated a rectified output voltage of 134 V by a 60 Hz stray magnetic field of home appliance, enabling to operate the f-μLED continuously. An optogenetic stimulator composed of MMTENG and f-μLED was implanted under a living mouse skull without mechanical damage. Image 1 • First demonstration of the optogenetic neuromodulation platform by stray magnetic field. • Enhancement of a maximum peak power by 260% via the flash-induced multiscale MMTEG. • Excellent thermal/mechanical stability and power efficiency of the vertical f-μLED. • Our research provides a novel therapeutic protocol for curing critical neurodiseases. [ABSTRACT FROM AUTHOR]

Designing a piezoelectric energy harvester (PEH) with high power density and high fatigue resistance is essential for the successful replacement of the currently using batteries in structural health monitoring (SHM) systems. Among the various designs, the PEH comprising of a cantilever structure as a passive layer and piezoelectric single crystal-based fiber composites (SFC) as an active layer showed excellent performance due to its high electromechanical properties and dynamic flexibilities that are suitable for low frequency vibrations. In the present study, an effort was made to investigate the reliable performance of hard and soft SFC based PEHs. The base acceleration of both PEHs is held at 7 m/s2 and the frequency of excitation is tuned to their resonant frequency (fr) and then the output power (Prms) is monitored for 107 fatigue cycles. The effect of fatigue cycles on the output voltage, vibration displacement, dielectric, and ferroelectric properties of PEHs was analyzed. It was noticed that fatigue-induced performance degradation is more prominent in soft SFC-based PEH (SS-PEH) than in hard SFC-based PEH (HS-PEH). The HS-PEH showed a slight degradation in the output power due to a shift in fr, however, no degradation in the maximum power was noticed, in fact, dielectric and ferroelectric properties were improved even after 107 vibration cycles. In this context, the present study provides a pathway to consider the fatigue life of piezoelectric material for the designing of PEH to be used at resonant conditions for long-term operation. [ABSTRACT FROM AUTHOR]

In2Se3 nanoparticles were synthesized in an aqueous solution without using any surfactant and then chemically transformed into CuInSe2 nanocrystals. The transformation was thermodynamically favorable and fast. The 93% production yield in mild reaction conditions allowed mass production of the CuInSe2 nanocrystals. By the virtue of the surface charges, the CuInSe2 nanocrystals were well dispersed in polar solvents. The surfactant-free nanocrystals enabled the formation of semiconducting CuInSe2 films on a flexible polymer substrate without any thermal treatment. We took advantage of this to fabricate a flexible UV photodetector. The current and sensitivity of the devices could be improved by utilizing CuInSe2 nanocrystals annealed at 160 °C in the reaction batch. On bending test, the detection sensitivity remained the same until the bending radius was reduced down to 4 mm. The dynamic response of the film device was stable and reproducible during light illumination (350 nm). [ABSTRACT FROM AUTHOR]

Titanium honeycomb substrates having TiO 2 surface with nano- to micro-sized pores were prepared by electrochemical anodization and used to make Pt-based oxidation catalyst monoliths without conventional oxide-based washcoat layers for pre-turbocharger catalyst (PTC) applications exposed to harsh conditions under very high flow rates of exhaust gas and engine vibration. Adhesion strength and CO/C 3 H 6 oxidation performance of the catalysts were compared with conventional washcoated FeCrAl monolith catalysts. The intermediate porous TiO 2 layer formation by the anodization can dramatically enhance the catalyst adhesion strength without sacrificing the catalytic performance under GHSV (gas hourly space velocity) higher than 100,000 h−1 for PTC. [ABSTRACT FROM AUTHOR]

A piezoelectric stack actuator (PSA) consisting of 28 lead magnesium niobate-lead titanate (PMN-PT) piezoelectric single crystal layers is developed. The free stroke and blocking force, which are the figures of merit of a PSA, are simulated through finite element analysis. The free stroke of the PSA samples measured using a laser displacement sensor was in the range of 6.4–8.0 µm at 200 V. In addition, the blocking force of the PSA samples measured using a custom-made system, consisting of a strain gauge, a motor and a load cell, was in the range of 191–226 N at 200 V. An analysis of seven samples exhibited that a large free stroke resulted in a blocking force of the PSA. [Display omitted] • The piezoelectric stack actuator consisting of 28 PMN-PT piezoelectric single crystal layers is designed and fabricated. • The systematic experimental setup to reliably measure the blocking force of the piezoelectric stack actuator is described. • The free stroke and blocking force of the piezoelectric stack actuators are characterized. [ABSTRACT FROM AUTHOR]