Emerging topological polar domains have a wide range of potential applications in electronic devices. It is critical to accurately manipulate these topological domains by electrical fields and explore their exotic properties for making more energy-efficient high-density non-volatile memories. Herein, we demonstrate that skyrmion-like polar nanodomains appear at room temperature in SrTiO3/PbTiO3 bilayer heterostructures by balancing the elastic and electrostatic energies via varying the SrTiO3 capping layer thickness. These polar nanodomains, stable at room temperature, can be electrically written, erased, and rewritten into the bilayer by applying an appropriate bias on the conductive tip of an atomic force microscope. The lateral size and location of these polar nanodomains can be precisely controlled. Moreover, ring-shaped conductive domain walls are observed around these polar nanodomains, with on/off ratios of more than two orders of magnitude with respect to the ferroelectric background. Based on these characteristics, the polar nanodomains can be created, erased, and probed electrically, suggesting applications for high-density ferroelectric hard disks.

It is only recently that the electric vehicle (EV) has evolved into a contemporary invention. There has been a rapid acceleration in the development of EVs in a number of nations in order to lessen their reliance on oil and their contribution to environmental pollution. In the tangible world, fully EVs do not release any carbon dioxide (CO2) emissions from their tailpipes, unlike any other conventional vehicles. This results in a 50%–70% CO2 reduction in air pollution per year. The achievement of electrification in transportation has led to a reduction in the weight and size of the vehicles as the need for internal combustion engines can be eliminated. Wide bandgap materials such as silicon carbide (SiC) and gallium nitride (GaN) offer advantages in the manufacturing of EVs. Beginning the late 2000s, the EV industry has begun to adopt GaN devices in their manufacturing processes. The semiconductor material GaN stands out as a material for power electronic systems in EVs owing to its high switching frequency, higher temperature limit, and high voltage breakdown. This review aims to provide a comprehensive overview of semiconductor GaN materials for EV applications, which could be useful to provide insights for researchers and scientists to accelerate their innovation for the improvement of EVs. This review begins with an introduction to EVs, followed by the anticipated demand for EVs. The application of GaN devices in EVs, compared to the traditional Si and SiC devices, which are the primary power devices in current EVs, is discussed. The recent advancement in GaN devices that are capable of being used in various components of a fully automated EV, such as the battery, energy storage system, auxiliary power unit, and motor drive, in addition to their use in different non-automotive vehicles such as electric aircraft, electric ships, electric railways, electric submarines, and heavy duty vehicles, is also discussed. Finally, the challenges posed by GaN devices and potential solutions to overcome these shortcomings have been addressed.

GeSe, composed of ecofriendly and earth-abundant elements, presents a promising alternative to conventional toxic lead-chalcogenides and earth-scarce tellurides as mid-temperature thermoelectric applications. This review comprehensively examines recent advancements in GeSe-based thermoelectric materials, focusing on their crystal structure, chemical bond, phase transition, and the correlations between chemical bonding mechanism and crystal structure. Additionally, the band structure and phonon dispersion of these materials are also explored. These unique features of GeSe provide diverse avenues for tuning the transport properties of both electrons and phonons. To optimize electrical transport properties, the strategies of carrier concentration engineering, multi-valence band convergence, and band degeneracy established on the phase modulation are underscored. To reduce the lattice thermal conductivity, emphasis is placed on intrinsic weak chemical bonds and anharmonicity related to chemical bonding mechanisms. Furthermore, extra-phonon scattering mechanisms, such as the point defects, ferroelectric domains, boundaries, nano-precipitates, and the phonon mismatch originating from the composite engineering, are highlighted. Additionally, an analysis of mechanical properties is performed to assess the long-term service of thermoelectric devices based on GeSe-based compounds, and correspondingly, the theoretical energy-conversion efficiency is discussed based on the present zT values of GeSe. This review provides an in-depth insight into GeSe by retrospectively examining the development process and proposing future research directions, which could accelerate the exploitation of GeSe and elucidate the development of broader thermoelectric materials.

Supercapacitors are widely acknowledged as crucial devices for storing and converting electrical energy, alongside batteries and fuel cells. Their ability to rapidly charge and discharge, typically within seconds or even milliseconds, makes them ideal for high-power applications. This feature provides significant advantages for electric vehicles, such as regenerative braking and hill-climbing, where quick energy transfer is essential. To optimize the power performance of supercapacitor cells, it is essential to focus not only on the active material but also on the inactive components, including binders, conductive agents, and separators. The latter functions as an electronic insulating barrier between the cathode and the anode while facilitating optimal ionic transport across the cell. Therefore, particularly in high-power devices, selecting suitable separators is crucial to ensure fast charging kinetics and minimal cell resistance. Despite significant progress in developing high-power electrode materials, relatively few studies have been dedicated to membranes and their impact on the cell's electrochemical behavior. Herein, we provide a practical guide for choosing appropriate membranes for high-power supercapacitor applications. A comprehensive description of the main characterization methods for reliable evaluation of separators, alongside practical experimental examples, is given below. A special discussion is devoted to the evaluation of membrane impedance by various analytical approaches.

Photoacoustic imaging, an emerging modality that seamlessly combines advantages of optical absorption contrast and ultrasound resolution, holds great promise for noninvasive imaging of biological tissues. Its applications span across diverse fields, such as dermatology, oncology, cardiology, and neurology. However, achieving accurate image reconstruction and physiological parameters quantification from raw photoacoustic signals presents a significant challenge. This challenge primarily arises from the inherent heterogeneity of tissues, encompassing variations in optical fluence and acoustic properties. In addition, incomplete information acquired from a limited view also leads to artifacts, image distortions, and reduced spatial resolution. Furthermore, robust spectral unmixing approach is another key step to restore the initial biochemical components' distribution with complex or unknown background absorption. To overcome these hurdles, researchers have proposed numerous state-of-the-art techniques, aiming to improve the accuracy and reliability of quantitative photoacoustic imaging (qPAI) in heterogeneous tissue. This review aims to comprehensively overview recent developments over the past decade, for addressing four main challenges frequently encountered in qPAI: limited-view reconstruction, acoustic heterogeneity, optical fluence fluctuations, and robust spectral unmixing, which serves as a reference for readers seeking to understand the specific challenges and corresponding solutions in this field.

The rapid success achieved from perovskite solar cell has drawn great expectations for commercialization of next-generation photovoltaics. Among the various perovskite materials, the inorganic perovskite derivatives have been of particular interest, ascribed to its superior thermal and chemical stability, which is a crucial criterion for reliable long-term operation. Nonetheless, the development of the efficient inorganic perovskite solar cells has been lagged from its organic–inorganic hybrid counterparts owing to the notorious phase-stability challenges associated with the formation of non-photoactive phases. The early progress of the inorganic perovskite solar cells has been centered on the stable perovskite phase-preparation and leads to the effective bulk management through intermediate engineering and compositional engineering strategies. Yet, challenges remain in securing the as-formed perovskite phase throughout the long-term operation. Accordingly, recent studies find interfacial modification strategies successful by constricting the phase-transformation channels in various perspectives such as defect propagation, strain, component segregation, charge accumulation, and external stresses. In this review, we start with the brief description on the inorganic perovskite solar cells and the associated advantages including chemical and optoelectronic properties. We then provide a review on the challenges of inorganic perovskite solar cells associated with the phase instabilities. We elaborate on the origins of the phase instabilities in terms of thermodynamics and the recently proposed channels including intrinsic factors and extrinsic factors that facilitate the detrimental phase transformation. Finally, we survey the recent successful approaches to stabilize the inorganic perovskite solar cells through interface managements and provide outlook on further progress.

Lanthanide-doped nanoparticles (LnNPs) show unique optical properties and have been demonstrated in various applications, including imaging, optogenetics, photothermal therapy, photodynamic therapy, light-controlled release/cross-linking, anticounterfeiting, lasing, sensing, and super-resolution microscopy. One of the key and urgent limitations of LnNPs is the weak and narrow absorption of lanthanides. Fabrication of heterostructures will overcome this hurdle and enhance the performance of LnNPs. Developing novel heterostructures to enhance the absorption of lanthanides and studying the energy transfer pathways and efficiencies are of broad interest to the chemical and physical research community. There is currently no systematic review to summarize different types of LnNP heterostructures. Thus, this review will summarize five types of heterostructures combining LnNPs with organic and inorganic dyes, plasmonics, semiconducting quantum dots, and metal–organic frameworks. The enhancement of absorption and the improvement of light conversion performance are compared and discussed. This review also discusses the energy transfer pathways and efficiencies between LnNPs and other components and provides suggestions to form heterostructures with enhanced absorption and efficient energy transfer for future applications. We hope this review will further inspire active development and study of lanthanide-based heterostructures with stronger absorption, better light conversion performance, and ease of multifunctionality.

Complex coacervation, a fascinating phenomenon rooted in liquid–liquid phase separation, plays a crucial role in numerous biological systems. This intricate process involves the segregation of a liquid into two distinct phases: a coacervate phase enriched with polymers and a polymer-deficient phase comprising the remaining dilute solution. The potential of coacervates extends beyond their natural occurrence in biological systems, as they possess the capability to encapsulate various types of biomolecules in an aqueous solution, obviating the need for organic solvents. Consequently, considerable efforts have been devoted to designing functional nanoscale coacervate-driven assemblies using both natural and synthetic polymers for a myriad of applications. In this review, we provide a synthesis and discussion of the formation of nanoscale polymeric assemblies driven by complex coacervation. This exploration delves into the fundamental driving forces underpinning the phenomenon and elucidates the diverse fabrication strategies employed. The various biomedical applications of these assemblies are highlighted, with a focus on their roles as drug carriers, gene delivery vehicles, antimicrobial agents, theranostic platforms, mucoadhesives, and nanoreactors. This review aims to contribute to a deeper understanding of coacervation-driven nanoscale assembly systems and their potential impact on the field of biomedical science and technology.

The precise detection of volatile organic compounds plays a pivotal role in addressing environmental concerns, industrial safety, and medical diagnostics. The accurate identification and quantification of these compounds because of their ubiquity and potential health hazards has fueled the development of advanced sensing technologies. This work presents a sensing system in the realm of long-wavelength infrared spectroscopy for achieving enhanced selectivity and sensitivity of benzene, toluene, and propane detection through quartz-enhanced photoacoustic spectroscopy. High-resolution gas spectroscopy is made possible by the use of specially designed InAs/AlSb-based quantum cascade lasers, emitting in the wavelength range 13–15 μm, and quartz tuning forks. The sensor system, characterized by its robustness and precision, demonstrates exceptional capabilities in benzene, toluene, and propane detection. The system's capacity for practical applications in environmental monitoring and medical diagnostics is demonstrated by its ability to distinguish these volatile organic compounds with a minimum detection limit of 113 ppb, 3 ppb, and 3 ppm for toluene, benzene, and propane at an integration time of 10 s, even in complex gas matrices. This work advances gas sensing technology while also offering insightful information on spectral interferences, a persistent problem in the field. The results usher in a new era of sophisticated and reliable gas sensing techniques meeting the growing demand for precise volatile organic compounds detectors for environmental monitoring purposes.

As a two-dimensional (2D) inorganic molecular van der Waals crystal, Sb2O3 has been widely recognized as an excellent dielectric and encapsulation material due to its wide bandgap, high dielectric constant (κ), and remarkably high air stability. Considering the significance and potential application of Sb2O3 in future electronic devices, it is valuable to summarize its recent advancements. In this review, we present the latest progress on 2D Sb2O3 flakes and films, encompassing synthesis methods, physical properties, and device applications. First, preparation strategies such as chemical vapor deposition, vertical physical vapor deposition, thermal evaporation deposition, liquid metal synthesis, and atomic layer deposition growth routes are highlighted. Subsequently, the mechanical properties and the phase transition mechanisms of 2D Sb2O3 are presented. Moreover, device applications, including encapsulation layer, photodetector, and gate dielectric, are demonstrated. Finally, we outline the future challenges and research priorities of 2D Sb2O3 materials.