Search Results (137)

Harsh-environment pressure sensing requires piezoelectric materials that can simultaneously withstand elevated temperature, mechanical loading, and structural degradation. GaN is a promising lead-free piezoelectric semiconductor owing to its wide bandgap, high thermal stability, and non-centrosymmetric wurtzite structure. However, its piezoelectric output can be significantly affected by free-carrier compensation in unintentionally n-type GaN. Here, we report a flexible all-inorganic piezoelectric pressure sensor based on a directly grown h-BN/GaN heterostructure thin film. The h-BN layer was deposited on GaN/Si by plasma-enhanced chemical vapor deposition, followed by backside Si removal, electrode deposition, and transfer onto a flexible Cu foil substrate. Structural characterizations confirmed the formation of a compact h-BN/GaN interface with clear lattice fringes, preferential out-of-plane orientation, and characteristic Raman signatures of both h-BN and GaN. Compared with the flexible GaN/Cu reference, the h-BN/GaN device exhibits modified interfacial electrical transport behavior, enhanced voltage and current-density outputs, and prolonged transient voltage retention. Finite-element simulations reveal modified electrostatic potential distribution after h-BN integration, while electrical and interfacial characterizations suggest electronic structure modulation and reduced carrier compensation effects at the heterointerface. Raman optothermal analysis indicates an improved relative/local thermal response of the h-BN/GaN device under identical optical excitation conditions, supporting its enhanced thermal robustness. Under 200 psi at 400 °C, the h-BN/GaN sensor maintains an output voltage of approximately 27.65 mV, about 2.32 times that of the GaN reference. This work demonstrates an interfacial engineering strategy based on two-dimensional h-BN integration for constructing flexible, thermally robust, and high-output piezoelectric sensors for harsh-environment monitoring. Full article

Organic–inorganic hybrid perovskites (OHPs) deliver certified single-junction power conversion efficiencies (PCEs) of up to 27.3% and National Laboratory of the Rockies (NLR)-certified perovskite–silicon tandem values of 34.85%, yet a substantial gap with the Shockley–Queisser (S–Q) limit persists. Grain-boundary (GB) defects are one principal contributor to this gap, driving non-radiative recombination, ion migration, and degradation alongside bulk, interfacial, contact-related, phase-related, and environmental loss channels. Rational passivation demands a non-contact tool capable of identifying and quantifying specific defect species in device-relevant thin films, a capability that conventional probes deliver only in part. This overview assesses the extent to which terahertz time-domain spectroscopy (THz-TDS, 0.2–2.5 THz) fulfills this role. Across five OHP compositions—MAPbI₃, MAPbBr₃, FAPbI₃, and FAPb(Br,I)₃ fabricated by sequential vacuum evaporation (SVE), together with solution-processed γ-CsPbI₃—the THz spectral window captures both intrinsic phonon modes and GB-localized molecular defect vibrations, enabling species-resolved characterization at room temperature. Notably, the oscillator strength of the SVE-specific 1.58 THz absorption in MAPbI₃ scales linearly with XPS-quantified CH₃NH₂ defect concentration, establishing a calibrated, contact-free proxy for defect concentration rather than an absolute defect count; the observable is the defect-induced perturbation of the Pb–X lattice, not the defect population itself. Building on these findings, we propose a three-pillar framework for THz-guided defect engineering: (I) quantitative defect measurement via oscillator-strength analysis, (II) material-specific fingerprint identification from a systematically constructed THz library, and (III) fingerprint-guided defect elimination with real-time feedback—together defining a closed-loop quality-control cycle that connects spectroscopic diagnosis to passivation strategy and, ultimately, to enhanced solar cell efficiency. Throughout, we distinguish capabilities demonstrated to date from extensions that remain proposals, and we define the measurement requirements needed before the framework can be transferred to inline manufacturing control. Full article

This work reports, for the first time, the use of agave bagasse from “Tequila Weber Var” as an efficient and eco-friendly template for the microwave-assisted solvothermal synthesis of C@TiO₂ photoelectrodes. The characterization of the C@TiO₂ materials was performed using composition and elemental analysis, diffuse reflectance/UV-visible spectroscopy, N₂ adsorption/desorption isotherms, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction patterns, cyclic voltammetry, impedance spectroscopy, and variations of the open-circuit potential in a conventional electrochemical cell. Three 1:1, 4:1, and 8:1 agave:Ti volume ratios were used to explore the influence of carbon content upon the optical and photoelectric properties of TiO₂. The composite with a 1:1 ratio showed a charge transfer kinetic capacity of 0.86 C·cm⁻²·s⁻¹ with the highest current density flow of 2.2 mA·cm⁻², and the lowest optical band gap (E_bg) value of 2.92 eV, boosting the optoelectronic behavior of TiO₂. The photoanode composed of FTO/C@TiO₂ with the hybrid material with a 1:1 ratio was preliminarily evaluated in a photovoltaic solar cell, showing a light-to-electricity conversion efficiency higher than the other two composites and up to 12.5 times higher than the photoanode only composed of neat TiO₂. The present results contribute to the state-of-the-art of eco-friendly organic–inorganic thin film photoelectrodes for the sustainable synthesis of third-generation solar cells using bagasse-derived waste as an efficient carbon source for the synthesis of hybrid photoactive semiconductors. Full article

As a novel membrane treatment technology, forward osmosis (FO) has become a research hotspot in the field of membrane technology owing to its advantages such as low energy consumption and low pollution. Nevertheless, this technology still faces notable limitations, including lower water flux than reverse osmosis (RO), difficult regeneration of draw solutions, limited commercial membrane types, and unavoidable reverse solute flux, which restrict its large-scale industrial application. This paper reviews the characteristics of forward osmosis membranes, the classification of draw solutions, the characteristics of membrane fouling, as well as the applications and development trends of forward osmosis technology. Common FO membranes include cellulose acetate (CA) membranes, thin-film composite (TFC) membranes fabricated by interfacial polymerization, and aquaporin (AQP)-based biomimetic membranes. According to the types of draw solutes, draw solutions can be classified into gaseous solutions, organic compound solutions, inorganic compound solutions, magnetic nanoparticle-based draw solutions, polymer gel draw solutions, etc. Since FO is operated without external hydraulic pressure, it exhibits lighter membrane fouling compared with pressure-driven membrane separation technologies. FO membrane fouling can be mainly divided into four categories according to fouling types: inorganic fouling, organic fouling, colloidal fouling, and biofouling. FO technology has a wide range of applications and plays an important role in seawater desalination, pressure-retarded osmosis (PRO) power generation, wastewater treatment and reuse, and the energy field. Notably, the reconcentration and regeneration of draw solutions remain major energy and economic limitations restricting the large-scale deployment of FO. As a promising treatment technology, with continuous technological advances in membrane materials and draw solutions, FO will play a significant role in the energy field, especially in lithium extraction from geothermal water, promoting the iteration of forward osmosis technology from a “water treatment technology” to a “core technology for energy and resource recovery”. Full article

The sol–gel method was employed to prepare organic–inorganic hybrid materials capable of accommodating large amounts of a sodium salt and a commercial ionic liquid. The resulting samples, obtained as thin and transparent films, were characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD) and atomic force microscopy (AFM). The samples exhibit thermal stability and are essentially amorphous, which encourages further investigation. Interest in sodium arises from the fundamental similarities between the electrochemistry of sodium and lithium batteries, as well as the analogous physicochemical properties shared by these two elements. Sodium-ion batteries have thus emerged as highly promising energy storage systems, particularly well-suited for stationary applications. Full article

Biomaterials are engineered to interact with biological systems for therapeutic or diagnostic purposes. Among them, natural biomaterials offer important advantages over many synthetic polymers, including intrinsic biocompatibility, non-toxicity and biodegradability. Silk fibroin, a fibrous protein derived mainly from Bombyx mori cocoons, has re-emerged as a particularly versatile platform because it combines favourable mechanical, thermal, electrical and optical properties with aqueous processing and tuneable degradation. In this review, we first summarise the key structural, physicochemical and functional properties of regenerated silk fibroin, including its mechanical behaviour, thermal stability, dielectric and piezoelectric response, optical transparency and low autofluorescence. We then describe how extraction and regeneration protocols are used to produce defined material formats—fibres and nanofibrous mats, porous 3D scaffolds and hydrogels, sub-micron particles, thin films and microstructured devices—and outline major functionalisation strategies, ranging from physical blending and encapsulation to covalent chemistry, genetic engineering of recombinant silk variants, and enzyme-mediated conjugation approaches. Building on this foundation, we critically examine biomedical applications of silk fibroin with a particular emphasis on (i) hybrid silk–fluorophore systems for bioimaging and biosensing (nanodiamonds, quantum dots and organic dyes), (ii) optical fibre, wearable and edible sensors for health and food monitoring, (iii) wound dressings and wound-sensing platforms, and (iv) tissue engineering scaffolds and drug-delivery depots. Finally, we discuss current limitations, including process variability, the trade-offs introduced by blending and cross-linking, and the challenges posed by non-degradable inorganic fillers and clinical translation. Together, these perspectives highlight silk fibroin’s potential and constraints as a multifunctional biomaterial for next-generation biomedical devices and theranostic systems. Full article

The bottleneck of service stability of perovskite solar cells is rooted in the mechanical failure of its active layer materials at the micro scale. In order to deeply understand this process, the nano-indentation mechanical response of all-inorganic perovskite CsPbBr₃ under pre-stress was studied by molecular dynamics simulation at the atomic scale. The core of this research work is to systematically reveal the quantitative influence of prestress, an inevitable initial stress state in the preparation and service of practical devices, on the near-surface mechanical behavior of materials. Firstly, the stress–strain response of the CsPbBr₃ model at 300 K, 350 K, and 400 K was verified. The temperature dependence of its mechanical properties and the consistency with the experimental values confirmed the reliability of the force field and simulation method. In addition, by applying a series of uniaxial pre-strains, we analyzed the influence of prestress on the evolution of the force-depth curve and indentation strain during nano-indentation. The results show that the introduction of pre-strain will induce the material to have a significant “softening effect” and systematically reduce its ability to resist the intrusion of the indenter. More importantly, this study quantitatively reveals the asymmetric influence of prestress direction: tensile prestress leads to more serious softening than compressive prestress with the same amplitude, indicating that materials are more prone to plastic deformation under tensile preload. This work clarifies the key regulation function of prestress on the mechanical properties of perovskite thin films and provides a crucial theoretical basis for constructing accurate cross-scale mechanical models and designing perovskite photoelectric devices with high reliability and fatigue resistance. Full article

Thin-film thermoelectric generators (TFTEGs) emerge as critical components of self-sustaining agricultural systems because they can utilize temperature gradients to generate plant-transpiration-induced thermovoltage signal quantifiable to plant health status. This study examines the latest developments in TFTEG materials, device structures, manufacturing processes, and their integration into agricultural systems such as plant-wearable, canopy-level and stem-clipped TEGs. Key questions addressed include the ideal materials for TFTEG fabrication, their biocompatibility and eco-stability in agricultural settings, recent design and AI-assisted optimization advancements, and future research directions in non-conventional TEG applications. The analysis consolidates evidence from inorganic, organic, and hybrid thermoelectric materials with respect to performance in terms of flexibility, thermal stability, output power, and biocompatibility. Bibliometric analysis was employed to determine dominant research topics and gaps, especially with respect to sustainability and AI-augmented design. The review emphasizes the latest breakthroughs in structural optimization, flexible substrates, encapsulation strategies, and sensor integration for reliability enhancement in field environments. In addition, applications of AI, including neural network-based conditional Generative Adversarial Network, surrogate modeling, and multi-objective optimization, are discussed in relation to the improvement of thin-film TEG design and simulation processes. This study suggests that TFTEGs exhibit great potential in agricultural monitoring and plant wearable applications but material toxicity, mechanical degradation, and integration with AI are still major obstacles. Full article

Background/Objectives: The increasing demand for aesthetics in dentistry has driven significant advancements in both materials and techniques. The primary cause of ceramic detachment in dental restorations is extensive mechanical stress, which often results in detachment and clinical complications. This study aims to improve the bond strength between NiCr-based metal frameworks and ceramic coatings by introducing biocompatible inorganic MeSiON thin films (Me = Cr or Zr) as interlayers. Methods: MeSiON coatings with a thickness of ~2 μm were deposited on NiCr alloy using cathodic arc evaporation. To tailor the stoichiometry, morphology, and mechanical properties of the coatings, the substrate bias voltage was varied: −50 V, −100 V, −150 V, −200 V. Structural and surface characterization was performed using SEM/EDS, XRD, profilometry, and contact angle analysis. The coating adhesion was evaluated by using standardized scratch testing, while the bond strength was evaluated using a three-point bending test. Results: The NiCr alloy exhibited a dendritic microstructure, and the ceramic layer consisted mainly of quartz, feldspar, kaolin, and ZrO₂. ZrSiON coatings showed superior roughness, elemental incorporation, and adhesion compared to Cr-based coatings, these properties being further improved by increasing the substrate bias. The highest bond strength was achieved with a ZrSiON coating deposited at −200 V, a result we attributed to increased surface roughness and mechanical interlocking at the ceramic-metal interface. Conclusions: CrSiON and ZrSiON interlayers enhanced ceramic-to-metal adhesion in NiCr-based dental restorations. The enhancement in bond strength is primarily ascribed to substrate bias-induced modifications in the coating’s stoichiometry, roughness, and adhesion. Full article

The research on ultra-thin inorganic chips is an important field in the development of inorganic flexible electronics. By thinning the inorganic (mainly silicon-based) chip to less than 50 μm, it will gain a certain degree of flexibility. After the ultra-thin chip is integrated into the flexible substrate, it is bent repeatedly during the operation of the system. When the bending angle is excessively large, the chip and substrate will debond, or the chip will break. In this process, whether the chip can be stably adhered to the substrate depends on many factors, and debonding can only be reduced by continuously adjusting the process parameters. From an energy method perspective, this study divides the bending process of flexible silicon-based chips and flexible films into two states: debonding and non-debonding. A debonding mechanical model of flexible chips is established, and the regulatory relationship between the adhesion coefficient between the chip and film, chip geometric size, and material parameters was established. Experiments were also conducted to verify the relevant theoretical results. The theoretical results show that the risk of chip debonding decreases with a reduction in chip thickness, an increase in interface adhesion, and an increase in bending radius. Improving the interface adhesion during the bending process can effectively stabilize the adhesion of flexible chips. This paper provides a theoretical basis for the integration and bending of ultra-thin flexible chips and flexible substrates, promoting the practical assembly and application of ultra-thin chips. Full article

Traditional materials synthesis often involves energy-intensive processes with significant waste generation and limited control over material properties. This review examines synthetic biology as a sustainable alternative for designing advanced materials with enhanced precision and versatility. It explores microbial biomineralization, detailing how microorganisms influence the formation of mineral deposits and participate in key biogeochemical cycles. It highlights recent research advancements in using a wide variety of microorganisms for the synthesis of inorganic materials such as metal and metal oxide nanoparticles, quantum dots, magnetic nanoparticles, and thin films. The review also discusses the production and properties of various biopolymers. Important factors that can influence the size, morphology, and uniformity of these biomaterials are covered in detail. Emphasis is placed on advancements utilizing synthetic biology tools, such as protein engineering and genome editing, and recent research for creating smart and responsive materials. Considering the present limitations of synthetic biology, challenges related to scale-up, yield, and uniformity are discussed, and suggestions for future research are detailed. Full article

The research considered in this publication aims to contribute to developing perovskite-based technologies by conducting basic research on perovskite materials. The materials described in the paper are thin films of hybrid perovskite MEAPbI₃ made using the PVco-D method in three different compositions—perovskite samples differ in the percentage of organic methylammonium and inorganic iodide parts. This publication discusses the influence of the composition of the thin perovskite layer on its structural and optical properties and the influence of the temperature of the environment of the perovskite thin film on optical properties. To answer these questions, the surface topography was analyzed using the AFM method, spectroscopic measurements were carried out in the UV-Vis-NIR range, and photoluminescence measurements were performed in a wide temperature range—from about 80 K to 310 K. The results indicate that the composition changes the surface topography, forming increasingly higher crystallites (up to 606%) with increasing methylammonium content. The transition temperature from the orthorhombic to the tetragonal phase was determined for each composition at about 140 K. For the composition of 30% MEAI + 70% PbI2, the phase transition temperature from tetragonal to cubic was determined at a temperature close to RT. Full article

Chemical vapor deposition (CVD) is a highly adaptable manufacturing technique used to fabricate high-quality thin films, making it essential across numerous industries. As materials fabrication processes progress, CVD has advanced to enable the precise deposition of both inorganic 2D materials, such as graphene and transition metal dichalcogenides, and high-quality polymeric thin films, offering excellent conformality and precise nanostructure control on a wide range of substrates. Conjugated conducting polymers have emerged as promising materials for next-generation electronic, optoelectronic, and energy storage devices due to their unique combination of electrical conductivity, optical transparency, ionic transport, and mechanical flexibility. Oxidative CVD (oCVD) involves the spontaneous reaction of oxidant and monomer vapors upon their adsorption onto the substrate surface, resulting in step-growth polymerization that commonly produces conducting or semiconducting polymer thin films. oCVD has gained significant attention for its ability to fabricate conjugated conducting polymers under vacuum conditions, allowing precise control over film thickness, doping levels, and nanostructure engineering. The low to moderate deposition temperature in the oCVD method enables the direct integration of conducting and semiconducting polymer thin films onto thermally sensitive substrates, including plants, paper, textiles, membranes, carbon fibers, and graphene. This review explores the fundamentals of the CVD process and vacuum-based manufacturing, while also highlighting recent advancements in the oCVD method for the fabrication of conjugated conducting and semiconducting polymer thin films. Full article

Chitosan and collagen are natural polymers widely used in biomaterials science; however, their inherent low stability and solubility present several challenges to obtain formulations suitable for potential clinical applications. In this study, tannic acid (TA) was employed as a cross-linker to improve the properties of thin films made from chitosan and collagen. In addition, potassium silicate (PS) was added as an inorganic filler, to produce innovative biocomposite films. The impact of TA and PS on physicochemical (i.e., material homogeneity, surface free energy, degradation, and stability roughness of surface), antioxidant, hemocompatibility, as well as cellular responses was evaluated. The results demonstrated that the incorporation of TA significantly enhanced the physicochemical properties of the chitosan/collagen-based films. The addition of 5% PS resulted in an increase in surface free energy and a decrease in roughness parameters. Furthermore, both surface free energy and cellular responses improved with the increased TA concentration in the biocomposite firms. Meanwhile, the hemolysis rate remained below 5%, indicating the potential suitability of these materials for medical applications, such as coatings or scaffolds for bone or skin wound healing. Full article

This paper reviews the recent development of organic–inorganic hybrid dielectric materials for application as gate dielectrics in thin-film transistors (TFTs). These hybrid materials consist of the blending of high-k inorganic dielectrics with polymers, and their resulting properties depend on the amount and type of interactions between the organic and inorganic phases. The resulting amorphous networks, characterized by crosslinked organic and inorganic phases, can be tailored for specific applications, including gate dielectrics in TFTs. As dielectric materials, they offer a synergistic combination of high dielectric constants, low leakage currents, and mechanical flexibility, crucial for next-generation flexible electronics. Furthermore, organic–inorganic hybrid materials are easily processed in solution, allowing for low-temperature deposition compatible with flexible substrates. Various configurations of these hybrid gate dielectrics, such as bilayer structures and polymer nanocomposites, are discussed, with an emphasis on their potential to enhance device performance. Despite the significant advancements, challenges remain in optimizing the performance and stability of these hybrid materials. This review summarizes recent progress and highlights the advantages and emerging applications of low-temperature, solution-processed hybrid dielectrics, with a focus on their integration into flexible, stretchable, and wearable electronic devices. Full article