Diamond possesses a multitude of excellent properties， with the highest hardness and thermal conductivity among natural materials， wide light transmission range and excellent electrical properties， making it significantly applicable in precision machining， electronic information， defense industry and aerospace. In recent years， the continuous advancement of microwave plasma chemical vapor deposition （MPCVD） technology has greatly expanded the application scenarios for diamond materials. Its end-use applications have gradually extended from the initial abrasive tools to high-end fields. Notable examples include the high-quality synthesis of diamond in the jewelry industry， efficient thermal management solutions for high-power electronic devices， superior infrared transmission and laser damage resistance in optical components， and emerging potential in semiconductor and quantum technologies. This paper systematically elaborates on the core principles and growth control methods of MPCVD diamond preparation technology. Following the logical mainline of technical principles， performance optimization， industrial applications and bottleneck breakthroughs， the study offers an in-depth analysis of the current status， key technical challenges and research advances across four major application domains： lab-grown diamond， thermal management， optics and semiconductors. Furthermore， combined with technological development trends and market demand， the future prospects in cutting-edge fields such as next-generation power electronics and aerospace are discussed in this paper， with the aim of providing theoretical insights and strategic directions for the technological advancement and industrial implementation of MPCVD diamond materials.

To address the urgent demand for high-energy-density of energy storage systems in electric vehicles and portable electronic devices， it is urgent to develop novel lithium-ion battery anode materials. Silicon suboxide （SiO_x， 0<x<2）， with its high theoretical specific capacity and structural stability brought by the incorporation of oxygen， is regarded as a highly promising high capacity anode material. However， the practical application of SiO_xstill faces challenges such as large volume variation （160%~200%）， low initial Coulombic efficiency， and poor electrical conductivity. This paper systematically reviews the structural models， lithium storage mechanisms， and modification strategies for SiO_x， including nanostructure design， composite material design， and prelithiation techniques. These approaches effectively alleviate the volume expansion of SiO_x， improve its conductivity and interfacial stability， and significantly enhance its initial Coulombic efficiency. Future efforts should focus on developing simple， scalable， and environmentally friendly preparation processes， aiming for high capacity and high initial Coulombic efficiency while comprehensively considering overall electrochemical performance， thereby promoting the practical application of SiO_xas anode material in high-efficiency energy storage systems.

Deep ultraviolet （DUV） light sources have promising application prospects in fields such as ultraviolet lithography， high-resolution spectroscopy， precise microfabrication， biomedicine， ultra-sensitive detection， and photochemistry. In practical applications， it is necessary to use deep ultraviolet birefringent devices such as polarizer/beam splitter， polarization beam splitter， phase retarder， optical isolation， and beam displacement to generate， modulate， separate and control polarized light. Currently， there is an extremely limited supply of commercial birefringent crystals suitable for the deep ultraviolet wavelength range. Calcium metaborate（Ca（BO₂）₂， abbreviated as CB₂） crystal is considered as a kind of deep ultraviolet birefringent crystal with promising application prospects， due to their large birefringence， short ultraviolet transmission cutoff edge and high ultraviolet band transmittance. Although the thermal properties of crystals are of paramount importance for both bulk crystal growth and subsequent device applications， the thermal behavior of CB₂ crystal has not yet been systematically investigated. Previously， only limited thermal data were available， with merely the thermal expansion coefficient reported within a narrow temperature range from 323 K to 873 K. CB₂ crystals were grown by the Czochralski method， and their thermal properties were systematically studied in this study. The thermal expansion coefficient was measured employing thermal dilatometer， specific heat capacity and thermal diffusivity were characterized by laser flash analyzer along different principal crystallographic directions. Thermal conductivity was calculated combining the measured specific heat capacity， thermal diffusivity， and the theoretical density of the crystal. The research results indicate that thermal expansion of the CB₂ crystal exhibits obvious anisotropy， and the average thermal expansion coefficients along the crystallographica，b， andc axes respectively areα₁₁=4.52×10^-6 K^-1，α₂₂=3.44×10^-6 K^-1 andα₃₃=2.91×10^-5 K^-1 within the temperature range from 323 K to 723 K. The microstructure analysis indicates that this is mainly attributed to the differences in the strength of chemical bonds along the different crystallographic axes. specific heat capacity shows a steadily increasing trend as a whole， ranging from 0.937 J/（g·K） to 1.242 J/（g·K）， indicating that it has a relatively high laser damage threshold. The thermal diffusivity and thermal conductivity gradually decrease as the temperature rises. Within the temperature range from 298 K to 723 K， the thermal diffusivities areA₁₁=0.734~1.755 mm²/s，A₂₂=2.199~4.361 mm²/s andA₃₃=0.529~1.196 mm²/s， respectively. Correspondingly， the calculated thermal conductivities areκ₁₁=2.366~4.353 W/（m·K），κ₂₂=7.089~10.818 W/（m·K） andκ₃₃=1.781~3.088 W/（m·K）， respectively. The thermal conductivity of CB₂ crystal also exhibits strong anisotropy. Due to the strong covalent bond （B—O bond） connecting along theb-axis direction， the phonon group velocity is extremely high in this specific direction， resulting in the maximum thermal conductivity. The research results of this paper provide detailed and reliable basic data for optimizing the temperature field design of single crystal growth， suppressing crystal cracking， and designing the thermal management for deep ultraviolet high-power optical devices.

Semiconductor radiation detectors have broad and surging applications in homeland security， medical imaging， and fundamental scientific research. Recently， the all-inorganic perovskite CsPbBr₃ has attracted considerable attention owing to its suitable bandgap （~2.3 eV）， high effective atomic number （65.9）， high density （4.85 g·cm^-3）， high resistivity （>10⁹ Ω·cm）， and excellent carrier transport properties （μτ on the order of 10^-3 cm²·V^-1）， making it a promising candidate for next-generation room-temperature semiconductor radiation detectors. Specifically， CsPbBr₃ crystals can be synthesized via either solution-growth or melt-growth techniques. Solution-based methods are typically carried out at relatively low temperatures and feature simple fabrication procedures and low cost. However， the size of solution-grown CsPbBr₃ crystals is generally limited to the centimeter scale. In comparison， melt-growth techniques are currently the most widely used methods for producing large-size CsPbBr₃ crystals. Nevertheless， melt growth is typically carried out at high temperatures using high-purity raw materials. Moreover， due to the relatively low thermal conductivity of CsPbBr₃， together with the structural phase transitions during the cooling process， defects such as twins and cracks are readily generated， severely deteriorating the single-crystal quality and detector performance.

In this work， the growth process of CsPbBr₃ crystals was systematically investigated using the vertical Bridgman method. Based on optimized growth parameters， including the temperature gradient and cooling rate， a high-quality large-volume CsPbBr₃ crystal with dimensions ofø40 mm×7 cm was successfully grown using zone-refined CsPbBr₃ polycrystals. The optical properties of the as-grown CsPbBr₃ crystals were systematically characterized. UV-Vis-NIR measurement revealed a high optical transmittance of up to 80% and a bandgap of 2.27 eV. Photoluminescence （PL） measurement showed a strong emission peak at 531 nm， while time-resolved photoluminescence （TRPL） spectra exhibited decay lifetimes of 2.26 and 38.62 ns， respectively. To evaluate the electrical properties， γ-ray detection performance， and charge transport properties， an asymmetric Au/CsPbBr₃/EGaIn planar device was fabricated. The CsPbBr₃ detector exhibited a high resistivity of up to 6.12×10⁹ Ω·cm determined by current-voltage （I-V） test. Owing to the asymmetric Schottky-type configuration， the dark current was effectively suppressed to 4.4 nA at -100 V， which was approximately two orders of magnitude lower than that measured at 100 V. In addition， the device exhibited a large ON/OFF ratio of 2 300 under a bias of -10 V using a white LED as the illumination source during current-time （I-t） test. The detector was subsequently evaluated using various γ-ray sources under a hole-dominant collection mode， achieving energy resolutions （ERs） of 10.0%， 5.5%， and 1.6% at room temperature for ²⁴¹Am （59.5 keV）， ⁵⁷Co （122 keV）， and ¹³⁷Cs （662 keV） γ-rays， respectively. Carrier transport properties， particularly high carrier mobility and long carrier lifetime， are critical for improving charge collection efficiency and radiation detection performance. Using a ²⁴¹Am γ-ray source， the hole mobility of CsPbBr₃ was determined to be 24.41 cm²·V^-1·s^-1 via time-of-flight （TOF） measurement， while the hole mobility-lifetime product was extracted to be 4.17×10^-3 cm²·V^-1 based on the Hecht equation. This work presents a reliable growth process for producing high-quality large-volume perovskite CsPbBr₃ with superior radiation detection performance， which may facilitate their scalable fabrication and practical applications.

Gallium oxide （Ga₂O₃） is a representative fourth-generation semiconductor with unique physical properties and the advantage of readily available large-area single crystals. These characteristics make Ga₂O₃ highly attractive for deep-ultraviolet photodetection and high-efficiency power electronic applications. Oxygen vacancies are among the most common intrinsic point defects in oxide semiconductors and play a crucial role in determining the material quality and device performance of Ga₂O₃. Therefore， effective control of oxygen vacancies in Ga₂O₃ single crystals is of significant practical importance. In this work，β-Ga₂O₃ single crystals were grown by optical floating zone method， which enables crucible-free growth and high material purity. A precisely controlled Ar/O₂ mixed atmosphere was employed to systematically investigate the effect of oxygen partial pressure on oxygen vacancy defect concentration inβ-Ga₂O₃ single crystals. With increasing oxygen content in the growth atmosphere， the optical transmittance ofβ-Ga₂O₃ single crystals is markedly enhanced， and the lattice ordering is significantly improved. Meanwhile， the defect-related photoluminescence emission is strongly suppressed. X-ray photoelectron spectroscopy analyses of the O 1s anion and Ga 3d cation states consistently demonstrate that the oxygen vancancy defect concentration decreases with increasing oxygen partial pressure. These results indicate that oxygen partial pressure is an effective parameter for regulating oxygen vacancy defect concentration inβ-Ga₂O₃ single crystals. This study provides practical guidance for the growth of high-quality oxide semiconductor single crystals.

Introducing multi-oxide layers into the structure of an anti-reflective vertical-cavity surface-emitting laser （VCSEL） simultaneously increased the output power and the side-mode suppression ratio （SMSR）. The n-type oxide layer， in particular， led to a substantial enhancement in both parameters. Contrary to the prediction of the standard core/cladding model， the SMSR increased alongside the effective refractive index difference between the core and cladding layers after the multi-oxide-layer introduction. This apparent contradiction is attributed to two mechanisms. First， in anti-reflective VCSELs， the anti-resonant mirror and optical reservoir significantly extend the cavity length， making diffraction loss for high-order transverse modes the primary factor governing the SMSR， rather than the core/cladding model. Second， the n-type oxide layer， located between the active region and the optical reservoir， spatially filters the oscillating beam by blocking a portion of the high-order modes， thereby suppressing their mode competition and improving the SMSR. This approach significantly improves the single-transverse-mode characteristics. To overcome the output power limitation of small oxide apertures， we implemented this multi-oxide-layer design in an anti-reflective VCSEL with a large 6 μm aperture. At an ambient temperature of 80 ℃ and an operating current of 5 mA， the triple oxide layer AR structure achieves an increase of 50.91% in output power and an improvement of 40.32% in SMSR compared to the single oxide layer AR structure.

Microwave plasma chemical vapor deposition （MPCVD） grown diamond thin film quality is dominated by process parameters and deposition apparatus. Taking a company’s MPCVD equipment as the research object， this study constructed resonant cavity simulation models via SolidWorks and COMSOL Multiphysics. Comparative analysis shows consistent electric field distribution between the two-dimensional axisymmetric and three-dimensional models. Based on the axisymmetric model， systematic plasma simulations were performed under varying power， pressure， and molybdenum stage height. Results show that increased input power flattens plasma distribution and significantly expands the excitation region above the deposition platform； higher pressure enhances plasma density but reduces cluster volume and distribution uniformity； a higher molybdenum stage also effectively improves plasma distribution uniformity. In this study， single-factor optimization was performed on the resonant cavity （overall and internal structure） to enhance plasma excitation efficiency and reduce heat dissipation pressure. This optimization results in an increase of the central electric field strength above the deposition stage to 473 276 V/m （26.4% higher than the pre-optimization value） and an 11.5% reduction in the coaxial segment’s secondary electric field strength. Based on single-factor optimization results， ten parameters were optimized via Box-Behnken design （BBD） and response surface methodology in this study， followed by a secondary optimization of four key factors. This multi-variable collaborative optimization further improves the central electric field strength by 5.5% compared to the single-factor optimization outcome， verifying the effectiveness of multi-variable collaborative optimization. This study provides theoretical support for MPCVD equipment parameter regulation， structural improvement， and process optimization.

In the study， a series of Eu³⁺ and Mn⁴⁺ singly doped and co-doped Ba₂SrWO₆ phosphors were successfully synthesized by high-temperature solid-state reaction method. The crystal structure， sample morphology， and spectral properties of the phosphors were characterized and analyzed using X-ray diffraction， scanning electron microscopy， and spectral analyzer. The results indicate that doping with Eu³⁺ and Mn⁴⁺ does not alter the crystal structure of Ba₂SrWO₆， with all samples maintaining a single pure phase. Under 325 nm excitation， Ba₂SrWO₆∶Eu³⁺/Mn⁴⁺ phosphors exhibit significant red emission， including the ⁵D₀→⁷F₁ characteristic transition of Eu³⁺ at 594 nm， the ⁵D₀→⁷F₂ characteristic transition at 615 nm and the ²E_g→⁴A_2g transition of Mn⁴⁺ at 695 nm. The emission peak positions in the co-doped system are consistent with those of the singly doped system. The composition with the highest luminous intensity is Ba₂SrWO₆∶7% Eu³⁺/0.6% Mn⁴⁺. Within the temperature range of 300~500 K， based on the fluorescence intensity ratio （I_Eu/I_Mn）， the maximum relative sensitivity reaches 0.87% K^-1 at 300 K， and the maximum absolute sensitivity is 0.005 9 K^-1 at 510 K. These results demonstrate that Ba₂SrWO₆∶Eu³⁺/Mn⁴⁺phosphors are used as candidate materials for efficient optical temperature sensing.

To address the increasing demands for large-size， thin photovoltaic silicon wafers in diamond wire cutting technology， and to overcome the limitations of conventional cutting fluids that rely on single functional additives to simultaneously achieve high lubricity， wettability， and foam resistance， a novel multi-component compounding strategy was adopted. This approach involved the construction of a composite lubrication system through the combination of water-based polyether and oil-based polyether， optimization of dynamic surface tension via compounding of alkyne glycol and fatty alcohol polyoxyethylene ether wetting agents， and identification of an alkyne alcohol polyether defoamer with both rapid and persistent antifoaming properties through systematic screening. The performance of the cutting fluid was systematically evaluated using laboratory friction and wear tests， dynamic surface tension analysis， and foam characteristic assessments， with its overall effectiveness further validated through industrial cutting trials. Laboratory results indicate that when lubricants were compounded at a ratio of 20% （mass fraction， the same below） water-based polyether and 2% oil-based polyether， the friction coefficient and wear scar width were reduced to 0.079 and 536.8 μm， respectively， demonstrating superior lubricating performance compared to commercial counterparts. After compounding the wetting agents at a specified ratio， the dynamic surface tension of the cutting fluid was observed to be lower than that of the reference sample across the entire bubble lifetime range. Field application results reveal that the A-grade rate of silicon wafers cut with the developed cutting fluid （QS-C-101） reaches 96.11%， accompanied by a chipping rate， total thickness variation （TTV）， and average wire mark value of 0.26%， 7.91 μm， and 7.69 μm， respectively. All key performance metrics were found to be superior to those of the mainstream commercial cutting fluid. Through the synergistic compounding of functional additives， a high-performance diamond wire cutting fluid with outstanding comprehensive properties has been successfully developed， offering an effective technical solution to enhance the quality and efficiency of large-size， thin silicon ingot cutting.

Perovskite materials show broad prospects in the field of new photovoltaic devices and high-performance photodetectors due to their excellent photoelectric conversion efficiency and adjustable band gap characteristics. However， perovskite has the problem of insufficient long-term stability under actual working conditions， which seriously restricts its large-scale commercial application. To address this critical bottleneck， this study proposed a molecular engineering strategy based on methyl deuteration （—CD₃）， which selectively replaced the hydrogen atoms on the methyl terminus of organic cations （CH₃NH₃⁺） in perovskites with deuterium （D） isotopes. This approach systemically enhances material stability without significantly altering the electronic structure of the material. Compared with the traditional deuteration treatment of the ammonium （—NH₃） site， the methyl deuteration strategy effectively avoids the inverse isotope effect that may arise from quantum tunneling effect of N—D bonds， thereby precluding the risk of potential stability decline. This study reveales that the introduction of deuterium atoms enables the modulation of material hardness and enhances its thermal stability. At the level of carrier dynamics， deuteration effectively suppresses the dynamic disorder of the crystal， thereby significantly enhancing the carrier lifetime of the material.

The development of wide-bandgap perovskite solar cells is limited by the high defect density and severe non-radiative recombination within their films. This study proposes the use of 4-methoxyphenyldiethylphosphonate （DM） as a multifunctional additive to mitigate these problems. The P＝O group in the DM molecule can form stable coordination bonds with under-coordinated Pb²⁺， effectively passivating defects. Simultaneously， its methoxy group regulates the local charge distribution through an electron-donating effect， thereby synergistically optimizing the crystallization process. Furthermore， the π-π stacking interactions between the benzene rings of DM molecules enhance the film's hydrophobicity， thereby improving environmental stability. The DM-modified wide-bandgap perovskite solar cell achieve a power conversion efficiency （PCE） of 22.08%. In contrast， the PCE of the control device without DM is only 18.89%. Furthermore， DM modification increase the open-circuit voltage （V_oc） from 1.082 V to 1.127 V， the short-circuit current density （J_sc） from 22.33 mA·cm^-2 to 23.78 mA·cm^-2， and the fill factor （FF） from 78.17% to 82.39%. The unencapsulated DM-modified device retained 91.2% of its initial efficiency after 30 d of storage at 25 ℃ and 10%~40% relative humidity， significantly outperforming the control device（85.3%）. These results strongly demonstrate the significant potential of DM as a functional additive for fabricating high-quality perovskite films and realizing high-performance devices， laying both experimental and theoretical foundations for its subsequent practical application.

Beta-gallium oxide （β-Ga₂O₃） has emerged as a highly promising ultra-wide band gap （~4.9 eV） semiconductor for next-generation power electronics and solar-blind ultraviolet photodetectors， owing to its exceptional breakdown electric field strength and high Baliga figure of merit. However， the intrinsically low intrinsic carrier concentration of β-Ga₂O₃ significantly limits its electrical conductivity and practical device performance. While doping engineering， particularly n-type doping with group-IV elements like Sn， has been extensively employed to modulate the electronic and optical properties， the inevitable incorporation of intrinsic point defect during crystal growth can profoundly influence doping efficiency through complex defect-dopant interactions. Despite previous investigations on isolated Sn doping， the synergistic effects between Sn dopants and intrinsic vacancy defects， as well as their combined impact on the optoelectronic properties of β-Ga₂O₃， remains insufficiently understood at the atomic scale. This work presented a comprehensive first-principles investigation based on density functional theory （DFT） to systematically elucidate the structural stability， electronic structure， and optical properties of Sn-doped β-Ga₂O₃ and its defect complexes with intrinsic vacancies （Sn_GaII-V_Gaiand Sn_GaII-V_Oi）. Calculations were performed using the Viennaab initio simulation package （VASP） with the projector augmented wave （PAW） method and Perdew-Burke-Ernzerhof （PBE） exchange-correlation functional. A 1×2×2 supercell containing 80 atoms was employed， with a plane-wave cutoff energy of 520 eV and a 3×5×3 Monkhorst-Packk-point grid. Defect formation energies were evaluated under both oxygen-rich and gallium-rich growth conditions to assess the thermodynamic stability of various configurations. The results demonstrate that Sn dopants exhibit a distinct site-selective preference in the β-Ga₂O₃ lattice， energetically favoring octahedrally coordinated Ga_II sites over tetrahedral Ga_I sites. The Sn_GaII configuration exhibits a significantly lower formation energy of -2.30 eV and minimal lattice distortion （x axis contraction of merely 0.24%， withy andz axes expanding by 0.10% and 0.12%， respectively）， compared to the Sn_GaI configuration. This preference is attributed to the larger ionic radius of Sn⁴⁺ （about 0.069 nm） relative to Ga³⁺ （about 0.047 nm） and the more flexible coordination environment of the octahedral site. Importantly， thermodynamic analysis reveals that Sn-doped β-Ga₂O₃ tends to form Sn_GaII-V_GaII defect complexes under oxygen-rich growth conditions， whereas such dopant-vacancy associations are suppressed under gallium-rich growth conditions， providing critical insights for defect engineering through growth atmosphere control. The electronic structure analysis indicates that isolated Sn doping introduces donor levels dominated by Sn-5s orbitals near the conduction band minimum， resulting in n-type conductivity with the Fermi level shifting into the conduction band. However， the introduction of gallium vacancies （V_Ga）—which act as triple acceptors—induces a pronounced self-compensation effect. In Sn_GaII-V_Gaicomplexes， the formation of V_Ga captures electrons from Sn donors， shifting the Fermi level downward and restoring the system to a high-resistance semi-insulating state. Conversely， oxygen vacancies （V_O） serve as deep donors， further increasing free electron concentration and enhancing conductivity when combined with Sn doping. Optical absorption calculations reveal that while Sn doping and vacancy complexes maintain the intrinsic deep-ultraviolet absorption edge suitable for solar-blind detection， the introduction of V_Ga vacancies creates a pronounced absorption band in the infrared-to-visible range （400~800 nm）. This arises from electronic transitions from occupied defect levels to the conduction band， significantly extending the photoresponse spectrum of β-Ga₂O₃ beyond the ultraviolet regime. These findings provide fundamental understanding of the formation mechanisms of defect complexes in Sn-doped β-Ga₂O₃ and their synergistic modulation of electronic and optical properties. By establishing the correlation between growth conditions， defect thermodynamics， and material performance， this study offers valuable theoretical guidance for optimizing doping strategies and designing high-performance β-Ga₂O₃-based optoelectronic devices and power electronics with tailored electrical and spectral characteristics.

Gallium oxide （β-Ga₂O₃） power devices have emerged as a prominent research focus owing to their advantages of high voltage resistance， low loss， and low cost-effectiveness. However， the development of β-Ga₂O₃ based homojunction devices remains impeded by the persistent challenge of achieving reliable and controllable P-type doping. Meanwhile， the heterojunction termination devices still have problems that the electrical characteristics such as high on-resistance and low breakdown voltage， which fail to meet the requirements of practical applications. To address the aforementioned issues， this paper innovatively proposed a composite terminal enhanced lateral NiO/β-Ga₂O₃ heterojunction field effect transistor （HJFET） consisting of a field-limiting ring and a floating field plate made of NiO. The effects of the length of the floating field plate and the length and thickness of the field-limiting ring on the breakdown characteristics of the device were studied in detail using the TCAD software. The results show that the combination of the field-limiting ring and the floating field plate can effectively alleviate the edge electric field concentration effect at the gate， and the high dielectric constant dielectric HfO₂ can regulate the edge electric field of the heterojunction to be within the channel of β-Ga₂O₃. Eventually， the device achieves a high breakdown voltage of 2 537 V. For the device with the floating field plate， a low on-resistance of 14.21 mΩ·cm²， a breakdown voltage of 2 358 V， and a PFOM of 391.285 MW·cm^-2 are obtained. The design of this study provides a new idea for the design and optimization of high-power and high-voltage gallium oxide power devices.

Transparent conductive materials have significant application value in the field of optoelectronic devices due to their combination of high visible light transmittance and good electrical conductivity. However， the development of high-performance p-type transparent conductive materials still faces challenges. Based on the first-principles calculations of density functional theory， this study systematically analyzed the electronic structure， optical properties and p-type conductive behavior dominated by intrinsic defects of RbYS₂. The calculation results show that RbYS₂ is an indirect bandgap semiconductor with a bandgap width of 3.30 eV. The optical property calculations indicate that RbYS₂ exhibits weak absorption in the visible light region， demonstrating good transparency. Calculations of mechanical properties indicate that RbYS₂ has good mechanical stability and exhibits obvious mechanical anisotropy. Further studies on intrinsic defects and carrier thermodynamics simulations reveal that under S-rich growth conditions， Rb vacancy V_Rb is the most favorably formed acceptor-type defect， with a formation energy of 1.14 eV， and a transition levelε（0/-） locates 0.225 eV above the valence band maximum（VBM）. When the defects are formed during high-temperature growth and their concentration is fixed at 1 200 K followed by rapid quenching to room temperature， the hole concentration of the system can reach 5.78×10¹⁸ cm^-3， presenting stable p-type conductive characteristics at room temperature while maintaining good optical transparency.

High-nickel layered ternary oxide LiNi_0.8Co_0.1Mn_0.1O₂ （NCM811） is a promising cathode material for lithium-ion batteries owing to its high specific capacity， high energy density， and cost-effectiveness. In this study， the first-principles calculations were employed to investigate the effects of Mg doping on the structural properties and lithium deintercalation properties of NCM811. The results indicate that Mg preferentially substitutes at Ni sites in NCM811. It shortens the Ni—O bond and increases its bond energy， thereby strengthening oxygen binding， effectively reducing oxygen release， and improving the structural stability of NCM811. Mg doping induces the oxidation of Ni²⁺ to Ni³⁺ in NCM811. During delithiation， both Ni²⁺ and Ni³⁺ serve as redox-active centers， ultimately oxidizing to Ni⁴⁺. Upon complete delithiation， the volume contraction of the Mg@NCM811 is smaller than that of pristine NCM811， indicating that Mg doping can suppress the lattice distortion and improve the structural stability of NCM811 during charge/discharge cycles.

Metamaterials， characterized by their unique bandgap properties， have garnered significant attention for their exceptional ability to attenuate vibrations. In this study， a novel multi-stable viscoelastic metamaterial configuration was designed， with its deformation controlled by adjusting the external loading rate. Specimen was fabricated using 3D printing technology， and uniaxial compression tests demonstrate that the unit cell of this metamaterial exhibits significant bistable deformation characteristics. The tunable bandgap characteristics and finite-period vibration transmission characteristics of this multi-stable viscoelastic metamaterial were investigated， and a comparative analysis was conducted with its undeformed configuration. The simulation results indicate that， compared to the undeformed case， structural deformation can significantly broaden multiple bandgaps of the multi-stable viscoelastic metamaterial within the 0~300 Hz range. Under the same compression level， the vibration suppression properties of the multi-stable viscoelastic metamaterial can also be altered by adjusting the external loading rate. Under quasi-static loading conditions， the multi-stable viscoelastic metamaterial can effectively suppress vibrations below 50 Hz. The proposed metamaterial exhibits significant viscous effects under dynamic loading， and compared to single-stable metamaterials， possesses more diverse bandgap tuning capabilities.

A new two-dimensional nickel（Ⅱ） coordination polymer ［Ni（pbc）₂（H₂O）］·2.5H₂O （1） ［Hpbc=2-（3-pyridyl）benzimidazole-5-carboxylic acid］ was successfully synthesized using a solvothermal synthesis method. Its chemical composition and structure were systematically characterized by infrared spectroscopy， elemental analysis， and single-crystal X-ray diffraction. The crystal structure analysis reveals that the central Ni²⁺ is in a six-coordinate ｛NiN₂O₄｝ environment， exhibiting a slightly distorted octahedral geometry. The deprotonated pbc^- ligand demonstrates versatile bridging capabilities by coordinating in two distinct modes：μ₂-κO∶κN andμ₂-κO，O'∶κN. Through these different coordination modes， the ligands connect adjacent nickel ions along thea-axis direction to form one-dimensional straight chains， and along theb-axis direction to form one-dimensional zigzag chains， respectively. These one-dimensional motifs are subsequently interlinked and extended into a coherent two-dimensional layered network within theab plane. This two-dimensional coordination network is further assembled into a three-dimensional supramolecular framework via intermolecular hydrogen bonds， which involve the participation of uncoordinated nitrogen and oxygen atoms from the ligands and the lattice water molecules. Topological analysis of this framework shows that the complex possesses a binodal （2，4）-connected network structure with the Schläfli symbol ｛8⁴·12²｝｛8｝₂. In addition， variable-temperature magnetic susceptibility measurements demonstrate weak ferromagnetic coupling characteristics in the mononuclear nickel complex.