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Gallium oxide (Ga2O3) emerges as a promising ultrawide bandgap semiconductor, which is expected to surpass the performance of current wide bandgap materials, like GaN and SiC, in electronic devices. However, widespread application of Ga2O3is hindered by its extremely low thermal conductivity and lack of effective device-level thermal management strategies. In this work, Ga2O3metal–oxide–semiconductor field-effect transistors (MOSFETs) are fabricated by conducting co-integrated design of substrate engineering with layer transferring and device packaging. 3D Raman thermography is introduced as a novel method to analyze the temperature distribution within the device, which provides valuable insights into their thermal performances. A high-quality Ga2O3-SiC heterogeneous integrated material is successfully fabricated with an extremely low interface thermal resistance of 6.67 ± 2 m2·K/GW. Compared to the homoepitaxial Ga2O3MOSFETs, the degradation of Ion/Ioffin Ga2O3-SiC MOSFETs is decreased by 1.5 orders of magnitude, and that of Ronis decreased by 31%, showing the great thermal stability of Ga2O3-SiC MOSFETs. With the additional device packaging, a significant one order-of-magnitude reduction in the thermal resistance of the Ga2O3-SiC MOSFET is achieved, reaching a record-low value of 4.45 K·mm/W in the reported Ga2O3MOSFETs. This work demonstrates an efficient strategy for device-level thermal management in next-generation Ga2O3power and RF applications.

Combining the hydrogen (H2) extraction process and organic oxidation synthesis in photooxidation–reduction reactions mediated by semiconductors is a desirable strategy because rich chemicals are evolved as byproducts along with hydrogen in trifling conditions upon irradiation, which is the only effort. The bifunctional photocatalytic strategy facilitates the feasible formation of a C═O/C─C bond from a large number of compounds containing a X–H (X = C, O) bond; therefore, the production of H2can be easily realized without support from third agents like chemical substances, thus providing an eco-friendly and appealing organic synthesis strategy. Among the widely studied semiconductor nanomaterials, ZnxCd1–xS has been continuously studied and explored by researchers over the years, and it has attracted much consideration owing to its unique advantages such as adjustable band edge position, rich elemental composition, excellent photoelectric properties, and ability to respond to visible light. Therefore, nanostructures based on ZnxCd1–xS have been widely studied as a feasible way to efficiently prepare hydrogen energy and selectively oxidize it into high-value fine chemicals. In this Review, first, the crystal and energy band structures of ZnxCd1–xS, the model of twin nanocrystals, the photogenerated charge separation mechanism of the ZB–WZ–ZB homojunction with crisscross bands, and the Volmer–Weber growth mechanism of ZnxCd1–xS are described. Second, the morphology, structure, modification, synthesis, and vacancy engineering of ZnxCd1–xS are surveyed, summarized, and discussed. Then, the research progress in ZnxCd1–xS-based photocatalysis in photocatalytic hydrogen extraction (PHE) technology, the mechanism of PHE, organic substance (benzyl alcohol, methanol, etc.) dehydrogenation, the factors affecting the efficiency of photocatalytic discerning oxidation of organic derivatives, and selective C–H activation and C–C coupling for synergistic efficient dehydrogenation of photocatalysts are described. Conclusively, the challenges in the applicability of ZnxCd1–xS-based photocatalysts are addressed for further research development along this line.

The development of perovskite direct X-ray detectors shows potential for advancing medical imaging and industrial inspection precision. To ensure the optimal energy conversion efficiency of X-rays for reducing radiation doses, it is necessary for perovskites with thicknesses reaching hundreds of micrometers or even several millimeters to be utilized. However, the nonlinear current response becomes uncertain with such high thicknesses. For instance, the prevailing theory regarding the rapid trapping and release of charges by shallow-level defects falls short in explaining the nonlinear current response observed in high-quality single-crystal samples. Moreover, a significant nonlinear current response can degrade the detection performance. Here, we elucidate peculiar parasitic and drift capacitance-induced nonlinear current responses in perovskites, which arise from bulk structural deficiencies and interface junction width variation in addition to shallow-level defects. Both theoretical analysis and experimental findings demonstrate the effective suppression of nonlinear current responses by establishing bulk heterojunctions and refining interface junctions. Consequently, we have successfully developed highly linear current-responsive detectors based on polycrystalline MAPbI3thick films. Notably, these detectors achieve a record sensitivity of 2.3 × 104μC·Gyair–1·cm–2under 100 kVpX-ray irradiation with a low bias of 0.1 V/μm, enabling enduring and high-resolution X-ray imaging for high-density objects. Successful fabrication and testing of a 64 × 64-pixel flat-panel prototype detector affirm the widespread applicability of these strategies in rectifying nonlinear current responses in perovskite-based X-ray detectors.

High-performance shape memory polymers with multifunctions are essential in sensors, wearable flexible electronics, artificial muscle actuators, and reversible morphing structures. In this work, a transparent and humidity-responsive shape memory polyurea featuring a high tensile strength (51 MPa), a high recovery stress (12 MPa) with an high energy output (0.98 J/g), and tolerance to extreme environments (retains great malleability at −196 °C) is prepared through constructing a bioinspired hard–soft nanophase structure and through hierarchical hydrogen bonding in the molecular network. The hard segment of a strong hydrogen bonding region is in charge of humidity-responsive behavior, and the soft segment of a weak bonding region provides the flexibility of the molecular chain. Furthermore, the periodicity of the phase-separated domains is 12 nm as characterized by small-angle X-ray scattering. The hydrogen bonding cross-linked network can be opened under the action of stress and re-bonded by heating, just like a zipper structure of reversible linking property. This unique molecular structure contributes to the humidity-responsive behavior of polyurea rolling up 160° in 20 s on the palm, as well as a high energy output lifting a 100 g weight exceeding 1631 times its own mass to 60 mm. The molecular structure of the hard–soft nanophase and the hierarchical hydrogen bonding offer an effective approach toward achieving a high-performance shape memory polymer with humidity-sensitive functions.

Sodium-ion batteries (SIBs), being an attractive candidate of lithium-ion batteries, have attracted widespread attention as a result of sufficient sodium resource with low price and their comparable suitability in the field of energy storage. However, one of the main challenges for their wide-scale application is to develop suitable anode materials with excellent electrochemical performance. Herein, a novel orderly layered VMoS2(OL-VMS) anode material was synthesized through a facile hydrothermal self-assembly approach followed by a heating procedure. As the anode material of the SIBs, the unique structure of OL-VMS not only facilitated the rapid migration of sodium ions between the stacked layers but also provided a stable framework for the volume change in the process of intercalation/deintercalation. In addition, vanadium mediating in the framework caused more defects to produce abundant storage sites for Na+. As such, the obtained OL-VMS-based anode exhibited high reversible capacities of 602.9 mAh g–1at 0.2 mA g–1and 534 mAh g–1even after 190-cycle operation at 2 A g–1. Furthermore, the OL-VMS-based anode delivered an outstanding specific capacity of 626.4 mAh g–1after 100-cycle testing at 2 A g–1in a voltage range from 0.01 to 3 V. In particular, even in the absence of conductive carbon, it still showed an excellent specific capacity of 260 mAh g–1at 1 A g–1after 130 cycles in a 0.3–3 V voltage range, which should contribute to the cost reduction and energy density increase.

A two-dimensional (2D) layer-structured material is often a high-capacity ionic storage material with fast ionic transport within the layers. This appears to be the case for nonconversion layer structure, such as graphite. However, this is not the case for conversion-type layered structure such as transition-metal sulfide, in which localized congestion of ionic species adjacent to the surface will induce localized conversion, leading to the blocking of the fast diffusion channels and fast capacity fading, which therefore constitutes one of the critical barriers for the application of transition-metal sulfide layered structure. In this work, we report the tackling of this critical barrier through nanoscale engineering. We discover that interconnected vertically stacked two-dimensional-molybdenum disulfide can dramatically enhance the cycling stability. Atomic-level in situ transmission electron microscopy observation reveals that the molybdenum disulfide (MoS2) nanocakes assembled with tangling {100}-terminated nanosheets offer abundant open channels for Li+insertion through the {100} surface, featuring an exceptional cyclability performance for over 200 cycles with a capacity retention of 90%. In contrast, (002)-terminated MoS2nanoflowers only retain 10% of original capacity after 50 cycles. The present work demonstrates a general principle and opens a new route of crystallographic design to enhance electrochemical performance for assembling 2D materials for energy storage.