CdZnTe (CZT) crystal has been considered as one of the most promising materials for room temperature semiconductor detector, with the advantages of high energy resolution, small volume and portability. With the rapid development of large-area CZT pixel detectors and the demand for high-energy and high-flux X-ray detection, higher requirements are put forward for the quality and size of CZT materials. In this paper, based from the basic physical properties of CZT crystal, the factors influencing the growth of large size CZT crystal were discussed. The research progress of two main CZT growth methods, Bridgman method and Travelling Heater method (THM) were summarized.

The temperature distribution of SiC single crystal growth cavity in PVT method is an important factor affecting the crystal quality. The effects of insulation structure, crucible structure and coil position on the growth temperature field of 6-inch SiC crystal were investigated by numerical simulation. The temperature distribution suitable for high-quality 6-inch SiC crystal growth is optimized. The 6-inch SiC crystal without cracks is successfully obtained through this temperature field. Also, the quality of the SiC wafer was characterized by high resolution X-ray diffraction, Raman spectroscopy and defect detection system. The results show that the crystal is single 4H-SiC, the micropipe density is less than 1 cm-2, the resistivity range is 0.02-0.022 Ω?cm, and the full width at half maximum of X-ray rocking curve is 21.6″.

High quality CdSe single crystal with diameter of 37 mm was grown by the modified vertical unseeded sublimation method, and the embryo of CdSe wave plate with size of 20 mm×20 mm×3 mm was cut along the optical axis. After grinding and polishing, the infrared transmittance test results show that the transmittance of the CdSe wave plate in the range of 6-12 μm was about 70%. In order to further increase the transmittance of the CdSe wave plate, the Essential-Macleod software-assisted design solution was adopted. YF3 and ZnS were selected as the two-layer anti-reflection coating materials, and the optimal film thickness was obtained. The coated CdSe wave plate had a transmittance of 90% in the 6-12 μm band, and the highest transmittance at 10.5 μm, with a peak of 99%.

The surface acoustic wave(SAW)properties in (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 single crystals poled along c at rhombohedral, tetragonal and morphotropic phase boundary be compared by the Christoffel equation with semi-infinite boundary conditions. The results show that 0.92Pb(Zn1/3Nb2/3)O3-0.08PbTiO3 single crystal near morphotropic phase boundary has better surface acoustic wave properties than the rhombohedral 0.955Pb(Zn1/3Nb2/3)O3-0.045PbTiO3 and tetragonal 0.88Pb(Zn1/3Nb2/3)O3-0.12PbTiO3. It is very apparent that the surface acoustic wave electromechanical coupling coefficient of 0.92Pb(Zn1/3Nb2/3)O3-0.08PbTiO3 single crystal is dramatically higher compared to tetragonal single crystal. Also, 0.92Pb(Zn1/3Nb2/3)O3-0.08PbTiO3 single crystal has low phase velocities and small power flow angles. Therefore, this crystal is very suitable in making SAW devices with superior electromechanical performance.

Relaxor ferroelectric single crystals were intensively investigated due to large piezoelectric effects near the morphotropic phase boundary (MPB). In general, materials with large ferroelastic responses may also have high acousto-optic effects. Especially, both large lattice parameter changes and stress induced phase transition can bring large refractive index changes, which enhances the overall acousto-optic effects. The acousto-optic coefficients π were characterized for 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (0.65PMN-0.35PT) single crystal under uniaxial stress using Mach-Zender interferometer method. The results show that the crystal exhibits very high acousto-optic values, for example, π33 can reach 15.2×10-12 m2/N, indicating that relaxor ferroelectric single crystals are promising candidates for laser deflectors or acousto-optic modulators.

The growth and deposition process of chemical vapor deposition boron-doped and nitrogen-doped diamond were explored by the first-principles plane wave pseudo-potential method based on density functional theory. The diamond substrate model with hydrogen termination surface and single nitrogen-substituted or single boron-substituted were established, and the optimal stable structure of these models was calculated. The adsorption process and the adsorption difficulty of different hydrocarbon groups (C, CH, CH2, and CH3), boron-hydrogen groups (B, BH, and BH2) and nitrogen-hydrogen groups (N, NH, NH2) on different substrates with active site were studied. The results show that boron atoms and nitrogen atoms can be doped into the diamond lattice by in-situ substitution, and the two-hydrogen-bearing groups (BH2, NH2) are the most favorable doping groups. The nitrogen atom is difficult to form a nitrogen dimer after substitution into the diamond crystal lattice, which cannot be heavily doped, but the boron atom is more likely to form a boron dimer, so its heavy doping can be achieved.

Aiming at the influence of the magnetic field line distribution of different superconducting transverse magnetic field structures on the solid-liquid interface of 300 mm Czochralski monocrystalline silicon, a coupling thermal lattice model based on the lattice Boltzmann method was adopted to solve the problem of coupling modeling of temperature and velocity fields. And three-dimensional numerical simulation of crystal growth under the superconducting magnetic field of the different structures was conducted. The result indicate that the oxygen content at solid-liquid interface is successfully lowered through the adoption of superconducting magnetic field with single magnetic line distribution; however, the heat distribution inside the melt is likely to be uneven. Adopting double magnetic line distribution may effectively perfect the axial temperature gradient that grows along the crystal and the radial temperature gradient that grows along the solid-liquid interface inside the melt. However, it has less restraining effect on the oxygen content at solid-liquid interface. When the crystal rotation and the crucible rotating were applied, the superconducting single magnetic line magnetic field structure is much better than superconducting double magnetic line magnetic field structure; besides, as the magnetic induction increases, the shape symmetry of the solid-liquid interface increases.

The crystal often cannot smoothly enter the body growth process from the shoulder growth process during crowning growth of Cz Silicon monocrystal growth due to the appearance of Broken Edge. To study the key characteristic parameters that affect Broken Edge, a method based on the Maximum Mutual Information(MIC) to identify the key characteristic parameters of the shoulder growth process of Cz-Si monocrystal growth were proposed. The correlation coefficients of the characteristic parameters to a Broken Edge problem each was calculated by the MIC method and the analytic hierarchy process (AHP). Then the first k terms were sequentially extracted in descending order until all feature parameters were used as input parameters for the Logistic Regression model to predict probability of Broken Edge. The results obtained show the accuracy of the model is the highest when the first 13 features of MIC extracted feature parameters were used as input parameters; and the MIC method is superior to the AHP method in prediction accuracy.

Based on first-principles, the formation energy, electronic structure and the magnetism of ZnO systems with the coexistence of Na doping and vacancy (VO or VZn) were calculated. Results show that there is the lowest formation energy when the relative distance between Na doping and vacancy(VO or VZn) is closest. Compared with the formation of VZn, Na doping is more likely to cause the occurrence of VO and excessive doping will inevitably lead to the occurrence of VO. Additionally, the magnetism of the system with the coexistence of Na doping and VZn is due to the intrinsic defect of Zn, while the electron-exchange interaction between Na doping and VO is the main reason for the magnetism of the ZnO system where Na doping and VO coexist.

Based on the density functional theory, the change of structure, energy band, conductivity, reflectivity and absorptivity of V-TiO2 of different concentration were investigated by first principle calculation. Intrinsic doping model of TiO2 and VxTi1-xO2(x=0.062 5, 0.125, 0.187 5)was established and the doping system is higher in conductivity with characteristics of N-type semiconductors. BP neural network was adopted to train the energy band results of the intrinsic doping model, and the data results of training model show that higher conductivity was achieved after doping and the energy gap was significantly reduced. Considering the above results, optimal conductivity and optical performance can be achieved when x=0.187 5.

Recently, two-dimension g-C3N4 based materials have received tremendous attention, ascribing to its short charge diffusion distance and sufficiently exposed surface active sites. However, the poor charge separation and light harvesting still remains a great challenge for their practical applications. Herein, phosphorene/g-C3N4 heterojunction was constructed by simple introducing phosphorene which own visible light response and high mobility, to promote charge separation and light harvesting. Meanwhile, phosphorene can be regarded as effective co-catalyst for g-C3N4 to reduce the barrier of charge transfer between photocatalyst and electrolyte interface, and thus suppress charge recombination and improve photocatalytic hydrogen evolution rate. Compared to pure g-C3N4, the phosphorene/g-C3N4 heterojunction presents not only better charge separation and lower charge recombination, but also wider light response. As a result, the photocatalytic hydrogen evolution rate as high as 1.08 mmol?g-1?h-1 is achieved for phosphorene/g-C3N4 heterojunction, which is 1.2 times higher than the pure g-C3N4.

The cyano-modified graphitic carbon nitride (g-C3N4) was successfully synthesized by a facile thermal condensation in air atmosphere using sodium acetate and melamine as precursor. The phase structure，morphology and optical properties of the catalyst were characterized by XRD, SEM, FT-IR, XPS, UV-Vis, PL and EIS. The synthesized cyano-modified g-C3N4 has high-efficient photocatalytic hydrogen production, H2 production rate (λ≥ 420 nm) of cyano-modified g-C3N4 is 4.5 times of that on pristine g-C3N4 because the cyano groups enhance the photo-generated electrons separation ability. Besides, the cyano-modified g-C3N4 exhibits better photocatalytic stability in the repeated photocatalytic hydrogen production process.

In order to improve the conversion efficiency of GaSb thermophotovoltaic cells, p+-GaSb window layer was introduced into the cell structure. The effects of bases, substrate temperature and reactant source temperature on the properties of p+-GaSb films were studied, the thickness and doping concentration of p+-GaSb window layer in the cells were optimized. The experimental results show that the structure and electrical properties of p+-GaSb films are affected by the bases and temperatures, and the performance of the cells can be improved significantly with thin and high doping p+-GaSb layers. Through the measurement and simulation, the conversion efficiencies of the thermophotovoltaic cells reaches 9.49% (AM1.5 measurement) and 20.34% (AFORS-HET simulation).

By capturing and converting carbon dioxide into energy storage materials, lithium carbon dioxide battery can reduce carbon dioxide emissions and serve as an innovative energy storage device, which has attracted extensive attention from researchers. However, the current lithium carbon dioxide battery still has a low discharge capacity, poor cycle performance and other shortcomings. In this paper, a non-binder self-supporting cathode material for lithium carbon dioxide battery was prepared by carbonizing natural pine wood, the discharge capacity (4.12 mAh?cm-2) and cycle performance (55 laps) of lithium carbon dioxide battery are greatly improved thanks to the multi-channel characteristics and self-supporting structure of biomass derived carbon. This method of using carbon derived from natural biomass as self-supporting cathode provides a new idea for improving the performance of lithium carbon dioxide batteries.

Rechargeable aqueous zinc-manganese dioxide (Zn-MnO2) batteries are one of promising systems for grid-scale energy storage applications, owing to their favorable merits such as low cost, environmental benignity and intrinsic operation safety. However, these batteries always suffer from poor cycling stability because of the low electric conductivity and poor structural stability of MnO2 cathodes, besides the detrimental dendrite growth and hydrogen evolution corrosion of Zn anodes. In this work, a hydrothermally-prepared Al-doped MnO2 as stable cathode material for aqueous Zn-MnO2 batteries were reported. The effects of Al doping on the phase, morphology, water content and electrochemical performance of MnO2 were systematically explored by X-ray diffraction (XRD), Energy dispersive spectroscopy (EDS), Fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS) tests. Equipment analyses indicate that Al doping not only transforms the product from micro β-MnO2into nano α-MnO2, but also improves the host material’s crystal water content. When used as cathodes of Zn-MnO2 batteries, the Al-doped MnO2 has a residual capacity of 150.1 mAh?g-1 after 500 cycles at a high current density of 1 A?g-1, much better than the undoped MnO2 (residual capacity=97.8 mAh?g-1 after 500 cycles). This research has certain enlightenment to the development of high-performance zinc-manganese batteries.

A2BB′X6 double perovskite become a hot spot and attract wide attention due to their stable structure, non-toxic, excellent properties, and low cost in solar cells field. In order to screen excellent double perovskite molecules, ten A2BNiX6 molecules with density functional theory were designed in this work. The structure stability, electronic and optical properties of these molecules were studied and their effects of elements at different positions on energy bands and optical properties were analyzed. The research results show that all the A2BNiX6 double perovskite were direct band gap semiconductors, which was to the benefit of the absorption of visible light. In particular, the band gap of four types of double perovskite of A2BNiF6 whose X position was F atom were 1.52-1.69 eV, which was very suitable as a light absorbing material. Optical properties research show that A2BNiF6 double perovskite are a transparent material and have a wide range of application prospects in transparent luminescent materials. Although there are some errors relative to hybrid functional, these studies provide theoretical support for light-absorbing materials for double perovskite solar cells.

The development of carbon-based oxygen reduction reaction (ORR) catalysts to substitute the expensive and unstable platinum-based ORR catalysts is of great importance for their optimal utilization in energy conversion and storage. Here, Zn, N codoped carbon with leaf-shaped was prepared using leaf-shaped Zeolitic Imidazolate Framework (ZIF-L) as precursor via thermal annealing under NH3. As a result, the as-synthesized Zn-N-C presents outstanding ORR onset-potential (0.95 V), half-wave potential (0.80 V), and diffusion limiting current density (5.57 mA?cm-2), that is similar to that at commercial Pt/C catalyst in alkaline electrolyte.

Based on the density functional theory, the first-principle calculation of the performance of single atom catalysts, MoS2 doped with several different elements (Fe, Ni, Cu, Zn, Pd and Si), was carried out by the Dmol3 module. Firstly, the bonding strength between the doped elements and the support was analyzed. It was found that Fe, Ni and Si have good bonding stability with MoS2. In addition, the performance of several X-MoS2 catalysts for CO oxidation was analyzed, and the adsorption energy of CO and O2 were calculated and compared. The following order was followed:Pd<Cu<Ni<Fe<Si. Among them, Si-MoS2 shows excellent catalytic properties, and the adsorption energy of O2 was the largest and significantly higher than that of CO. The E-R mechanism analysis shows that it would be conducive to the efficient activation of O2 at the catalytic active site and ensure the next CO oxidation reaction. The analysis of local density of states show that the interaction between Si and O2 near Fermi level is stronger than that of CO, so the adsorption of O2 is stronger than that of CO. Si doped MoS2 has the potential to be a catalyst for CO oxidation.

N-type Bi2Te3 nano-powders were prepared by hydrothermal method, using [P123(polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer), PVP (polyvinylpyrrolidone), and EDTA (ethylene diamine tetraacetic acid)] as template agents. Moreover, the n-type Bi2Te3thermoelectric bulk samples were prepared by Spark Plasma Sintering technology (SPS). The phase, morphology and thermoelectric properties of the prepared samples were characterized by XRD, SEM, ZEM-3 and laser thermal conductivity. The results show that most of the Bi2Te3 nanoparticles prepared by the three template agents are flake-shaped. Among them, the PVP-made nanosheets are the most regular, the EDTA-made nanosheets are not uniform in size, and the P123-made nanosheets are mixed with rod-like and agglomerated spherical shapes; XRD patterns show that the as-prepared nano-powders are all pure Bi2Te3 phase without other impurities. The research on the thermoelectric properties of bulk samples found that:due to the unique layered structure of Bi2Te3, which would affect the carrier and phonon transmission, the ZT value of the prepared bulk sample perpendicular to the pressure direction was larger than that parallel to the pressure direction. The Bi2Te3 sample prepared by the PVP template presented the best thermoelectric performance and the ZT value reached 0.33 at a temperature of 480 K.

Monodisperse dendritic mesoporous silica nanospheres (DMSNs) with enlarged diameter and extremely tiny pore size were synthesized by brominated dodecyl trimethyl ammonium bromide which is a relatively short carbon chain surfactant and acts as template agent. The as-prepared DMSNs-C12 were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourie tansform infrared spectroscopy (FT-IR), N2 adsorption-desorption isotherms to reveal its morphology, crystal texture, chemical compositions, pore volume and specific surface area. The results indicate that the particle size of DMSNs-C12 greatly increases, wrinkled structure disappears and the pore size significantly declines, compared with DMSNs fabricated with conventional cetlytrimethyl ammonium bromide as emplate agent (noted as DMSNs-C16). The reason could be that the mutual repulsive force of surfactants decreases with the reduction of carbon chain which affects microemulsion formation, giving rise to structural difference.

BiVO4 nanopowders was synthesized by carbon adsorption coprecipitation method. Its physical and chemical properties were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), specific surface area (BET), ultraviolet visible spectrophotometer (UV-Vis), infrared spectroscopy (FT-IR) and thermogravimetric analyzer (TG-DTG), respectively. The photocatalytic property of prepared samples was investigated using methyl orange (MO) as pollutant and 500 W dysprosium lamp as light source. The results show that BiVO4 powders prepared by carbon adsorption coprecipitation method has the advantages of uniform distribution, smaller particle size and less agglomeration compared with the powders prepared by ordinary precipitation method. Meanwhile, the light absorption wavelength of the powder calcined at 600 ℃ was red-shifted compared with other temperatures, which enhanced the absorption capacity in the visible light range. The photodegradation of methyl orange results show that the degradation rate of BiVO4 powder prepared by carbon adsorption coprecipitation method was 96% within 120 min.

The effect of annealing on varistor properties of TiO2-Ta2O5-CaCO3 varistor ceramics was studied. TiO2-Ta2O5-CaCO3 varistor ceramics were prepared by the traditional ball mill-molding-sintering method, then these varistor ceramics were annealed at different temperatures. The nonlinear coefficient α and varistor voltage EB of these samples were tested with varistor DC parameters and their microstructures were analyzed by XRD, SEM and STEM. The result shows that annealing at suitable temperature for appropriate time can make the grain grow up slightly, which results uniform grain sizes, less porosity and higher grain density. During annealing, the acceptor ions with larger radius obtain kinetic energy and move towards the grain boundary. The state density of acceptor increases at the grain boundary will improve the nonlinear coefficient α. The number and total area of grain boundaries decrease with grain grown properly, which is helpful to reduce the varistor voltage. At the same time, the densification of grains increases and the resistivity decreases, which further reduces the varistor voltage. When doping concentration is 0.20mol%, and sintering temperature is 1 350 ℃, TiO2-Ta2O5-CaCO3 varistor ceramic annealed at 700 ℃ for 3 h obtains the highest nonlinear coefficient and lower varistor voltage (α=8.6, EB=22.5 V?mm-1), which is better than TiO2-Ta2O5-CaCO3 varistor ceramic unannealed.

With the increasing of the thermal field size of the straight-pull method, the C/C composite crucible-holder has been widely used to replace the graphite crucible-holder in the production of single crystal silicon. However, due to the high temperature and Si-riched environment, the crucible-holder made of carbon fibers are easy to disassimilated, the high frequency of replacement increases the production cost to the enterprise. In this paper, the phase at different stages of carbon fiber’s dissimilar coating were analyzed by XRD, and the morphology of the dissimilar coating was studied by SEM. It was found that carbon fiber turned into silicon carbide in the high temperature and Si-riched environment. By analyzing the flow field and temperature field of the monocrystalline silicon furnace, the formation process and mechanism of silicon carbide were revealed.The main reasons for the dissimilarity were analyzed. The results can provide theoretical support to prolong the service life of the crucible-holder.

Using SiO2, CaO and MgO as main raw materials, basic glasses were prepared by traditional high temperature melting process, and diopside glass-ceramics were prepared by one-step crystallization heat treatment method. The effects of heat treatment temperature and time on crystallization and thermal conductivity of diopside glass-ceramics were studied by X-ray diffraction, scanning electron microscope and laser thermal conductivity meter respectively. The results show that with the increases of heat treatment temperature, the crystallinity of glass-ceramics increases, the grain size increases, and the thermal conductivity first increases and then decreases. With the increases of heat treatment time, the grain size of glass-ceramics increases, and the thermal conductivity first increases and then decreases. When the heat treatment temperature is 890 ℃, the heat treatment time is 120 min, the heating rate is 10 ℃/min, the grain size of glass-ceramics is 0.3-0.4 μm, the crystallinity is 79%, and the thermal conductivity reaches the maximum value of 2.59 W/(m?K).

ASV (Low-E film system/SiO2/VO2) and ASVS (Low-E film system/SiO2/VO2) composite film system were prepared on a single silver Low-E glass substrate by magnetron sputtering, and a thermochromic near-infrared isolation film system was obtained. Through UV-NIR spectrophotometer, XPS, XRD and SEM, the effects of VO2 thickness and SiO2 antireflection layer on the permeability and thermal insulation of the film system were studied. The results show that in the range of 20-90 ℃, the near infrared average transmittance Tnir of ASV film system decreases with the increase of temperature, with the increase of VO2 thickness, Tnir decreases, and the selection coefficient Q increases first and then decreases. When the thickness of VO2 is 50 nm, the increment of near-infrared insulation performance ΔTnir at 90 ℃ is 18.56%, and Q is 96.59%. Compared with ASV film system, ASVS film system has 16.88% higher visible light transmittance, while Tnir remains unchanged at 90 ℃, and Q is 102.4%. Its performance is better than ASV film system.

Trans-stilbene(TSB) crystal is an excellent scintillation material which can be used for fast neutron detection in strong γ ray environment. Because of the superiority of solution growth in crystal quality and performance, it is necessary to study the growth technique of TSB crystal in solution systematically. This paper has introduced the process and progress of TSB crystal growth by solution cooling method at home and abroad, analyzed the research results, and pointed out the problems that have yet to be solved in the growth process of TSB solution.

Solar cell is a kind of inexhaustible energy, and its development in the commercial field was limited owing to its low efficiency seriously. In recent years, the synthesis and application of graphene and its derivatives have been rapidly developed. Due to its excellent electrical, mechanical and optical properties, graphene and its derivatives are expected to be applied to improve solar cell efficiency and replace the traditional transparent conductive oxide. In this paper, the application of graphene as conductive electrode, carrier transport material and stabilizer in solar cell is reviewed.

The ternary metal sulfide CuSbS2 is a kind of earth-abundant and eco-friendly solar cell light absorber layer material, and has characteristics such as high light absorption coefficient, suitable band gap and low melting point. It is expected to be used in building integration, public infrastructure and portable electronics. This paper first summarized the different preparation methods of CuSbS2 thin film by various teams in recent years, and summarized the effects of Cu content and heat treatment on film quality, and then introduced the latest research progress on solar cells, such as the design of cell devices and improvement of conversion efficiency, etc. Finally, the development trend of CuSbS2 thin film solar cells was forecasted.

Graphite carbon nitride (g-C3N4) is a non-metallic semiconductor material with visible light response. g-C3N4 has the characteristics of low cost and easy availability, stable physical and chemical properties, non-toxic and non-polluting, and has good application prospects in the field of environmental purification and energy catalysis. However, the bulk phase g-C3N4 has such shortcomings as small specific surface area, poor visible light absorption ability, and high recombination efficiency of photogenerated electrons and holes, which severely limit its application in practice. In this paper, based on the introduction of the structure, characteristics and preparation methods of g-C3N4, the modification methods of g-C3N4 are mainly summarized, including the research progress of the modification methods such as element doping, morphology control, precious metal deposition and so on. Finally, the reaction mechanism of g-C3N4 in photocatalytic reaction is discussed, and the research of g-C3N4 photocatalyst in the field of purification of water environment is prospected.