JOURNAL OF SYNTHETIC CRYSTALS

Wet Oxidation of Semiconducting Silicon Carbide Wafers

LU Xuesong, WANG Wantang, WANG Rong, YANG Deren, PI Xiaodong

2024, 53(2): 181-193.

Asbtract ( 196 )

PDF (9989KB) ( 358 )

References | Related Articles | Metrics

Semiconducting silicon carbide (4H-SiC) exhibits characteristics of high hardness, notable brittleness, and excellent chemical stability. The commonly employed technique for achieving an ultra-smooth and flat surface is chemical mechanical polishing (CMP), which is utilized to process the 4H-SiC surface. Wet oxidation, as an important process of chemical-mechanical polishing of single-crystal 4H-SiC, directly affects the rate and surface quality of CMP. This paper provides a comprehensive overview of the current research status of wet oxidation of single-crystal 4H-SiC. It discusses the oxidants used in the wet oxidation of 4H-SiC, such as KMnO₄, H₂O₂, K₂S₂O₈. Based on this, it further summarizes commonly employed oxidation-enhancement methods, including photocatalytic-assisted oxidation, electrochemical oxidation, and Fenton reaction. The mechanism of wet oxidation of single-crystal 4H-SiC is analyzed from the aspect of theoretical calculation, and the future research direction of wet oxidation of 4H-SiC is proposed.

Synthesis of Doped Diamond by High-Pressure and High-Temperature: a Review

HAO Jinglin, DENG Lifen, WANG Kaiyue, SONG Hui, JIANG Nan, KAZUHITO Nishimura

2024, 53(2): 194-209.

Asbtract ( 129 )

PDF (13611KB) ( 171 )

References | Related Articles | Metrics

Diamond possesses an ultra-high thermal conductivity and a wide band-gap. Its electrical resistance could be adjusted for the semiconductor application by increasing the electron and vacancy content introduced by doping different elements. Therefore, diamond is thought to be the final wide band-gap semiconductor materials. This paper firstly introduces the synthesis of diamond by high-pressure and high-temperature (HPHT) method, and then systematically reviews the current status and developments of diamond doping by HPHT. The effects of single-element doping, such as N, B, P, and S, as well as multi-elements co-doping in the diamond crystal growth and its electrical properties are analyzed. In additional, this paper summaries the study diamond doping using first-principle calculation. HPHT annealing could effectively change the combinations of doped elements and the associated vacancies and their distribution. This paper reviews the adjustment of nitrogen-related color centers in diamond by HPHT annealing, elucidating the formation mechanisms of various nitrogen-related color centers. Finally, This paper prospects the potential optical and electrical properties of doped diamonds, highlighting the importance of theoretical calculations and experimental methods for multi-element co-doping investigation to enhance the performance of doped diamonds.

Analysis and Review of Influencing Factors of SiC Homo-Epitaxial Wafers Quality

GUO Yu, LIU Chunjun, ZHANG Xinhe, SHEN Pengyuan, ZHANG Bo, LOU Yanfang, PENG Tonghua, YANG Jian

2024, 53(2): 210-217.

Asbtract ( 198 )

PDF (5600KB) ( 230 )

References | Related Articles | Metrics

The performance and lifetime of silicon carbide (SiC) devices are directly affected by the quality of SiC epitaxial films. On the one hand, the quality of SiC epitaxial films is affected by the quality of substrates. For examples, the stacking faults (SF) in substrates penetrate into the epitaxial layer, forming bar-shaped stacking faults (BSF), and the threading screw dislocation (TSD) penetrate into the epitaxial layer to form pits or Frank-type stacking faults (Frank SF). On the other hand, the quality of SiC epitaxial films is also influenced by the epitaxial growing process. For examples, basal plane dislocation (BPD) in the substrate form Σ-basal plane dislocation (Σ-BPD) in the epitaxial layer under thermal stress or other unstable conditions, the TSD and threading edge dislocation (TED) in the substrate may be etched and derived into pits, and SF and silicon droplets may also be produced. Therefore, high quality SiC substrates and optimized epitaxial growing process are both crucial for obtaining high-quality silicon carbide epitaxial wafers. In this article, based on the SiC epitaxial films grown on 6 inch SiC substrates batch-produced by TankeBlue Company, the defects reproducing process in substrates during epitaxial growing were analyzed, and the formation mechanism and controlling technology of common defects such as BPD, SF, silicon droplets and pits were overviewed. The generation mechanism of Σ-BPD and its eliminating methods were also explored. Finally, we obtained the mass-production technologies of SiC epitaxial films with good thickness and concentration uniformity, and low defect density, which are qualified for making 650 and 1 200 V SiC-based MOSFETs.

Research Progress on Metal Organic Frameworks Proton Conductor and Their Applications in Proton Exchange Membranes

FU Fengyan, WANG Xiaohong, GAO Zhihua, XING Guang'en, ZHANG Yan, FAN Pei

2024, 53(2): 218-230.

Asbtract ( 66 )

PDF (6927KB) ( 35 )

References | Related Articles | Metrics

Proton exchange membranes (PEMs) have key functions in fuel cells. They separate the cathode and anode, provide channel for proton transport, and block the fuel permeation in the battery. Perfluorosulfonic acid membrane like Nafion has excellent chemical stability, thermal stability, and high proton conductivity. However, it also has problems such as high cost, poor mechanical performance and low proton conductivity at high temperatures, and easy degradation. Metal organic frameworks (MOFs) are attractive candidates for PEMs due to their high porosity, large specific surface area and controllable internal channels. MOFs have been used as proton conductors directly, or to modify and improve the existing ionic polymer PEMs, and a series of important progresses have been achieved. In this paper, four common proton conduction modes of MOFs structure proton conductors are reviewed, and the related studies of MOFs in different types of ionic polymer composite PEMs are summarized. Moreover, current issues on MOFs proton conductors and their PEMs are pointed out, which provides references and ideas for the development and application of MOFs as PEMs.

Design of Large Size NaI (Tl) Growth Crystallization Furnace

YAN Ping, LI Yong, HE Gaokui, WANG Qiang, WANG Guobao, ZHENG Yulai

2024, 53(2): 231-237.

Asbtract ( 108 )

PDF (5111KB) ( 120 )

References | Related Articles | Metrics

NaI (Tl) scintillators are widely used because of their characteristics of high detection efficiency, good temporal characteristics, and minimal temperature influence. In order to meet the needs of nuclear radiation detectors with high detection efficiency, large size and high energy resolution NaI (Tl) scintillators are required. Based on the growth characteristics of NaI (Tl) crystals, the main furnace body, temperature field system, crucible, heating power supply and other components of the large size NaI (Tl) growth crystallization furnace were studied and designed. In conjunction with the control system of the large size NaI (Tl) growth crystallization furnace, innovative fusion method was used to grow NaI (Tl) scintillator materials with a diameter exceeding 300 mm, which provides direction and solutions for the subsequent growth of large size NaI (Tl) crystals in China.

Characterization Method for Internal Defects in Laser Crystals Based on Slice Beam Scanning

QIAN Mengxue, ZHANG Zhirong, WANG Huadong, ZHANG Qingli, SUN Yu

2024, 53(2): 238-245.

Asbtract ( 87 )

PDF (3490KB) ( 69 )

References | Related Articles | Metrics

Large size laser crystals are a key component of high-power all solid-state lasers. However, during the crystal growth process, defects such as bubbles and inclusions are inevitably generated, which affect the performance of the laser. In order to quickly and effectively evaluate crystal defects, a three-dimensional imaging system for crystal defects based on sheet beam scanning was established in this paper. In the system, a Powell lens is used to shape a 532 nm point laser to obtain a sheet-like laser. The scattered light generated by crystal defects is obtained through a telecentric lens and CMOS detector to obtain the surface distribution of crystal defects. At the same time, high-precision displacement platforms are used to scan the surface array one by one, completing the three-dimensional distribution scanning of the crystal. Furthermore, combined with digital image processing technology, characterize the surface distribution characteristics of crystal defects and reconstruct the volume distribution characteristics of crystal defects. Based on the above system, intrinsic defects in Yb∶YAG crystals with dimensions of about 50 mm×50 mm×100 mm were measured with a minimum defect detection resolution of 38.69 μm. This article provides a new method for accurately characterizing the internal defects of crystals, and also provides visual data support for high-precision processing of crystal billets in the later stage.

Negative Refraction Characteristics of Acoustic Hyperbolic Configuration Metamaterials

LIU Song, ZHAO Renjie, DU Yifan, WU Fang, SONG Hebin, GAO Peng

2024, 53(2): 246-251.

Asbtract ( 47 )

PDF (3948KB) ( 16 )

References | Related Articles | Metrics

Acoustic hyperbolic metamaterials are artificial materials with hyperbolic dispersion characteristics and strong anisotropy. Their negative refractive properties are the theoretical basis for studying the implementation of high-resolution focused superlenses. In response to the problem that the recognition of far-field noise sources is limited by the resolution of 0.5 times wavelength acoustic Rayleigh diffraction recognition, combined with the excellent control effect of acoustic metamaterials on sound waves, a hyperbolic metamaterial that can achieve sub wavelength super-resolution imaging is introduced, and its negative refractive characteristics are used to design an acoustic hyperbolic structure for working at a frequency of 2 271.5 Hz. The dispersion and negative refraction characteristics of the hyperbolic structure of this configuration were analyzed, and the results show that, the group velocity direction of sound waves propagating in this hyperbolic metamaterial is perpendicular to the wave vector and follows the normal direction of the dispersion curve. The research in this paper provides some design references for realizing arbitrary regulation of sound wave and elastic wave, as well as focusing, locating, identifying and amplifying noise sources.

Study on vdW Epitaxy Mechanism and Stress Modulation of Large-Size GaN Microwave Material

LI Chuanhao, LI Zhonghui, PENG Daqing, ZHANG Dongguo, YANG Qiankun, LUO Weike

2024, 53(2): 252-257.

Asbtract ( 58 )

PDF (4845KB) ( 35 )

References | Related Articles | Metrics

Based on metal organic chemical vapor deposition (MOCVD), growth mechanism and stress modulation of van der Waals (vdW) heteroepitaxial GaN microwave material were studied with few-layer BN as an interlayer on 4-inch sapphire substrates. The influence of AlN nucleate process on growth mechanism of GaN buffer layer and its correlation with crystalline quality, stress, and electrical properties were discussed. A stress modulation scheme based on AlN/AlGaN composite nucleation process is proposed, achieving stress well in control for large-size vdW heteroepitaxy firstly. The as-grown GaN microwave material possesses a wafer bow of +20.4 μm, fullwidth at half maximum of GaN (002)/(102) peaks of 471.6/933.5 arcsec, root-mean-square roughness of 0.52 nm and electron mobility of 2 000 cm²/(V·s). Finally, large-size wafe-scale GaN microwave material was successfully separated from sapphire substrate by a mechanical lift-off process, providing convenience for transfering to high thermal conductivity substrates and creating conditions for fabricating high-power RF devices.

First Principles Study on Mechanical Properties, Electronic Structure and Optical Properties of Ni, Cu, Zn Doped Tetragonal PbTiO₃

WANG Yunjie, ZHANG Zhiyuan, WEN Dulin, WU Zhencheng, SU Xin

2024, 53(2): 258-266.

Asbtract ( 45 )

PDF (6555KB) ( 31 )

References | Related Articles | Metrics

The mechanical property, electronic structure, and optical properties of tetragonal perovskite PbTiO₃ and Ni, Cu, Zn-doped PbTiO₃ were studied by first principles. The mechanical property calculations show that Ni-doped PbTiO₃ exhibits the highest values for volume modulus, shear modulus, and elastic modulus among the three doping systems. Notably, the Ni-doped system also has the highest Debye temperature. The G/B ratio represents the material's brittleness and toughness, which is highest for Zn-doped PbTiO₃, indicating the highest degree of chemical bond orientation. The G/B range for Ni and Zn-doped systems is 0.56<G/B<1.75, indicating brittle materials, while the intrinsic PbTiO₃ and Cu-doped systems have G/B values less than 0.56, indicating ductile materials. The electronic structure reveals that the doped systems have narrower band gaps and reduced transition energies compared to the intrinsic system. The introduction of Ni introduces impurity levels at the Fermi energy level in PbTiO₃, while Cu and Zn doping shifts the valence band maximum upwards, causing the Fermi level to enter the valence band and resulting in p-type conductivity for Cu and Zn-doped PbTiO₃. The doping of Ni, Cu and Zn expands the absorption range of PbTiO₃ to the infrared region and enhances the absorption intensity in the visible light range. Among the intrinsic PbTiO₃ and three single-doped PbTiO₃ materials, Cu-doped PbTiO₃ exhibits the best photocatalytic properties.

First Principles Study of Magneto-Optical Kerr Effect of Double Perovskite Oxide A₂BOsO₆(A=Sr, Ca; B=Cr, Mo)

LIU Pai, ZU Ningning, LI Rui

2024, 53(2): 267-275.

Asbtract ( 36 )

PDF (6378KB) ( 33 )

References | Related Articles | Metrics

Sr₂CrOsO₆ has the highest magnetic transition temperature (725 K) among the double perovskite oxides. Ca₂CrOsO₆ was obtained by replacing Sr ions with smaller volume Ca ions, and the magnetic transition temperature was higher than room temperature. Further substitution of Cr ions by Mo ions with more delocalized d orbitals yielded Ca₂MoOsO₆. The electronic structures and magneto-optical Kerr effects of the double perovskite oxides Sr₂CrOsO₆, Ca₂CrOsO₆ and Ca₂MoOsO₆ have been systematically calculated by density functional theory. The electronic structures indicate that all three materials are semiconductors. The electronic structures of Sr₂CrOsO₆ and Ca₂CrOsO₆ are very similar, and the band gap of Ca₂MoOsO₆ is extremely small, only 0.10 eV. Observing the magneto-optical Kerr effect line, all three materials show significant magneto-optical Kerr effects in the range of infrared to visible spectrum. The maximum Kerr rotation angles of Sr₂CrOsO₆, Ca₂CrOsO₆ and Ca₂MoOsO₆ are 1.18°, 0.98° and 0.65°. The maximum Kerr rotation angle of the three materials is greater than 0.2°, which makes them to be ideal magneto-optical materials. The calculated results show that the inclusion of both 3d(4d) and 5d transition metal ions in the compound contributes to the significant magneto-optical Kerr effect. Analysis of the optical conductivity tensor shows that the peak of the magneto-optical Kerr line of three materials originates from the interband transition and is dominated by the imaginary part of the off-diagonal element of optical conductivity tensor.

Dielectric Loss Regulation and Efficient Electromagnetic Wave Absorption of Cu_xS_y-MoS₂ Heterostructure

JIANG Xiao, LI Bo, HE Bang, ZENG Xiaojun

2024, 53(2): 276-285.

Asbtract ( 39 )

PDF (17430KB) ( 35 )

References | Related Articles | Metrics

Molybdenum disulfide (MoS₂) has attracted much attention in the field of electromagnetic wave (EMW) absorption due to its high specific surface area and unique electronic structure, but its high conductivity leads to poor EMW absorption performance. To address this issue, this work introduces Cu_xS_y nanoparticles and constructs a unique Cu_xS_y-MoS₂ heterostructure to achieve appropriate impedance matching and attenuation capabilities. By regulating Cu_xS_y nanoparticles, the dielectric loss capacity of heterostructure is adjusted. As a result, Cu_xS_y-MoS₂ exhibits excellent EMW absorption performance at low, medium and high frequencies. The Cu_xS_y-MoS₂ heterostructure shows a reflection loss (R_L) of -72.77 dB at a frequency of 12.68 GHz, with a matching thickness of only 1.99 mm, surpassing most metal sulfide heterostructures. Moreover, it also exhibits a wide effective absorption bandwidth (EAB), reaching 5.1 GHz (12.9~18.0 GHz) at 1.73 mm. This work provides a new strategy for designing MoS₂-based absorption materials with strong absorption, broadband and thin matching thickness.

Modification of Anatase TiO₂ (101) Surface by Doping Rare Earth Yttrium

ZHU Liyuan, WANG Zhiwen

2024, 53(2): 286-292.

Asbtract ( 44 )

PDF (7884KB) ( 31 )

References | Related Articles | Metrics

Using first-principles calculations, the different doping structures and electronic properties of Y atom on anatase TiO₂(101) surface were carefully studied to improve the photocatalytic activity of the surface. The results show that when Y atom is adsorbed on stoichiometric anatase TiO₂(101) surface, the most stable adsorption site is between two 3-fold coordinated oxygen atoms. Meanwhile, when Y atom on anatase TiO₂(101) surface with subsurface oxygen vacancy, the most stable adsorption site is between two 3-fold coordinated oxygen atoms that neighboring subsurface oxygen vacancy. In contrast, when Y atom on anatase TiO₂(101) surface with surface oxygen vacancy, the most stable adsorption site is on the top of 3-fold coordinated titanium that neighboring surface oxygen vacancy. The charge density results show that Y atom can be stably adsorbed on anatase TiO₂(101) surface. Furthermore, the density of states results show Y doped on the surface with surface oxygen vacancy can suppress the band gap from 1.67 eV to 1.44 eV, and induce extra impurity energy levels, which cause a fractional transition of electrons and improve surface photocatalytic ability. This study provides theoretical support for enhancing the surface photocatalytic ability of TiO₂ (101) by single atom Y doping.

Synthesis, Structure and Characterization of a Strontium Complex

BAO Yuting, LIANG Yinong, SUN Zan

2024, 53(2): 293-299.

Asbtract ( 53 )

PDF (3958KB) ( 45 )

References | Related Articles | Metrics

A Sr(II) complex [Sr(L)₂(H₂O)₄]_n (1) was synthesized with 1,4,5,8-naphthalene tetracarboxylic acid (H₄L1) and strontium chloride hexahydrate under solvothermal conditions. The structure was characterized by elemental analysis (EA), single crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), infrared spectroscopy (IR) and thermogravimetric analysis (TGA). The single crystal X-ray diffraction results indicate that H₄L1 undergoes in-situ reaction to generate 1,3-dioxo-1H,3H-benzo[de]isomere-6,7-dicarboxylic acid (H₂L). In complex 1, each Sr(II) atom is located in the geometric configuration of a square antiprism. The L^- ligands connect Sr atoms to form a one-dimensional chain structure. 2D supramolecular structure is formed through hydrogen bonding and π…π stacking interactions. The solid states luminescence behavior of complex 1 was explored. It is found that complex 1 produces a wide emission spectrum band (450~690 nm) at the excitation wavelength of 211 nm, and the maximum emission wavelength appears at 535 nm. Therefore, it can be seen that complex 1 is a potential green light material.

Study on the Structure and Catalytic Property of a Novel Benzenesulfonate-Imidazole Complex

QI Jinyang, WANG Min, YANG Ruijie, ZHANG Yingchun, SONG Zhiguo

2024, 53(2): 300-306.

Asbtract ( 50 )

PDF (4519KB) ( 22 )

References | Related Articles | Metrics

A novel benzenesulfonate-imidazole complex of nickel Ni(Im)₆(C₆H₅SO₃)₂ was synthesized by solvothermal method with nickel sulfate, sodium benzenesulfonate and imidazole as main raw materials. The structure, composition and thermal stability of complex were characterized by single X-ray crystal diffraction, inductively coupled plasma optical emission spectrometer, infrared spectroscopy, powder X-ray diffraction and thermogravimetric analysis. The molecular structure was determined. The specific surface area and the pore structure were determined by N₂ adsorption-desorption test. The result shows that the complex belongs to monoclinic system, P2₁/c space group, exhibiting a 3D spatial structure. It exhibits high phase purity and thermal stability. The cell parameters of complex are a=8.377 3(4) Å, b=10.151 8(5) Å, c=20.526 3(10) Å, α=90°, β=90.292 0(10)°, γ=90°, V=1 745.63(15) Å³, Z=2, M_r=781.52, F(000)=812, μ=0.737 mm^-1, D_c=1.487 g·cm^-3, R₁=0.042 1, wR₂=0.110 3. Then, the Knoevenagel reaction was used as a probe to test the catalytic performance of complex. The experimental results show that under room temperature and solvent-free conditions, the complex could complete catalytic reactions in a relatively short time and exhibit high catalytic activity.

Synthesis, Structure and Fluorescence Sensing Property of Manganese Metal-Organic Framework Based on 5-Aminonicotinic Acid

JIANG Tao, LIANG Xiaotong, LIAO Siyan, LIU Xiaohui, YU Jiajun, ZOU Lin, QIU Yanxuan

2024, 53(2): 307-314.

Asbtract ( 40 )

PDF (6083KB) ( 24 )

References | Related Articles | Metrics

A new three-dimension manganese(II) metal-organic framework [Mn₂(5-ana)₄(H₂O)]_n (namely Mn-MOF) has been successfully constructed by the reaction of 5-aminonicotinic acid (5-Hana) and MnCl₂ using solution method at room temperature. The structure and properties of Mn-MOF were characterized by X-ray single-crystal diffraction, X-ray powder diffraction, elemental analysis, infrared spectroscopy, thermogravimetric analysis, ultraviolet-visible spectra and luminescent spectra. Structural analysis reveal that the as-synthesized complex crystallized in the monoclinic system and feature a binodal (2,8)-connected coordination network. The [Mn₂(CO₂)₂(H₂O)] dimeric unit acts as 8-connected node and 5-ana^- ligand acts as 2-connected node. Electrostatic potential (ESP) on molecular van der Waals surface analysis of 5-ana^- ligand shows that the first reactive site exists in the surface close to the oxygen atoms of carboxyl group with the ESP global minimum of -143.37 kcal·mol^-1. The second and third reactive sites exist in the nitrogen atoms of pyridine ring and amino, respectively. Mn-MOF displays good thermal stability at room temperature. Fluorescence spectroscopy measurement reveals that the complex shows emission maximum at 402 nm upon 256 nm light excitation. More importantly, Mn-MOF exhibits sensing selectivity for Fe³⁺ by fluorescence quenching with the quenching efficiency up to 98.71%, which makes it as a potential luminescent sensor for analyzing Fe³⁺ in aqueous solution.

A Coordination Polymer Constructed by Tetranuclear Copper Cluster Units and Its Photocatalytic Degradation Properties

PAN Huibin, WU Tingting, GE Jing, HUANG Peipei, TUO Mengqi, LU Jiufu

2024, 53(2): 315-321.

Asbtract ( 51 )

PDF (6998KB) ( 18 )

References | Related Articles | Metrics

A coordination polymer [Cu₂(μ₃-OH)(1,3-BIP)(BTC)]_n (SNUT-20) was constructed by 1, 3-di(1H-imidazol-1-yl)propane (1,3-BIP), benzene-1,3,5-tricarboxylic acid (H₃BTC) and Cu(NO₃)₂·3H₂O under solvothermal method. Its structure was confirmed by elemental analysis (EA), thermogravimetric analysis (TGA), FT-IR and single crystal X-ray diffraction. Single crystal X-ray diffraction exhibits that SNUT-20 is a 3D framework with a tetranuclear copper cluster as a secondary structural unit, which forms a binodal (3, 8)-connected topology by further ligation of mixed ligand. In addition, SNUT-20 exhibits good photocatalytic degradation performance for rhodamine B (RhB), methylene blue (MB) and methyl orange (MO), RhB, MB and MO reach 81.5%, 89.4% and 48.3% of the degradation rates, respectively.

Luminescence Properties of Non-Rare Earth Activated Thermal Stability Blue-Violet Zn₃B₂O₆∶Bi³⁺ Phosphor

SHENG Xingxing, LYU Jinbin, XIAO Feng

2024, 53(2): 322-328.

Asbtract ( 38 )

PDF (7707KB) ( 14 )

References | Related Articles | Metrics

The rapid development of modern completely artificial light-controlled plant growth requires the light source increasingly stringent. Blue-violet phosphor with high luminous intensity and good thermal stability is the key material for plant growth. Herein, narrow-band blue-violet Zn₃B₂O₆∶xBi³⁺ (0≤x≤0.03) phosphor with excellent thermal stability was synthesized by solid-state reaction. The results of XRD and energy spectra analysis show that Bi³⁺ successfully entered Zn₃B₂O₆ lattice. The fluorescence spectrum of Zn₃B₂O₆∶Bi³⁺ phosphor shows narrow-band blue-violet light at 430 nm (³P₁~¹S₀), and the full width at half maximum is only 56 nm. The optimal Bi³⁺ doping concentration is 0.02. According to the excitation spectrum shape and the lifetime decay behavior, it is proved that Bi³⁺ only occupies Zn sites in Zn₃B₂O₆. The emission peak intensity and integrated area of Zn₃B₂O₆∶0.02Bi³⁺ phosphor at 423 K are both 85% of those at room temperature, indicating that the sample has excellent thermal stability and may have potential application in high-temperature devices. The emission spectrum of Zn₃B₂O₆∶0.02Bi³⁺ phosphor accounts for 70.4% and 84.6% of the absorption spectra (370~525 nm) of chlorophyll a/b, respectively, indicating the potential application of as-prepared blue-violet phosphors in the field of plant growth.

Boron Doping Technology for the Front Polysilicon Layer of Full TOPCon Cells

ZHANG Bo, SONG Zhicheng, NI Yufeng, WEI Kaifeng

2024, 53(2): 329-335.

Asbtract ( 109 )

PDF (5225KB) ( 106 )

References | Related Articles | Metrics

In order to improve the efficiency of tunneling oxide passivated contact (TOPCon) cells, a p-type tunneling oxide passivation contact structure was fabricated on the front of N-type TOPCon cells through high-temperature diffusion, improving the emitter passivation performance and reducing front metal recombination. The effects of different deposition time, drive-in temperature, drive-in time and other process parameters on the passivation performance and doping curve of experimental samples were investigated. The experimental results show that when the deposition time is 1 500 s, the drive-in temperature is 920 ℃, and the drive-in time is 20 min, the boron doped polysilicon layer can achieve better passivation performance and boron doping concentration, with the doping concentration of sample polycrystalline silicon layer reaching 1.40×10²⁰ cm^-3. The implied open circuit voltage(iV_oc) is greater than 720.0 mV. The photoelectric conversion efficiency of TOPCon cells prepared based on this parameter can reach 23.89%, corresponding to a short-circuit current density of 39.36 mA/cm², the open circuit voltage (V_oc) is 726.4 mV, and the fill factor (FF) is 83.54%

Preparation of Polymorph MnO₂-Ru Composite Catalyst and Its Electrocatalytic Performance for Oxygen Evolution in Water

LI Jia, YUAN Zhongchun, YAO Mengqin, LIU Fei, MA Jun

2024, 53(2): 336-343.

Asbtract ( 38 )

PDF (11061KB) ( 17 )

References | Related Articles | Metrics

The introduction of heteroatoms into manganese dioxide (MnO₂) is an effective method to adjust the active site of electrochemical water oxidation catalysis. Although many modification methods for MnO₂ have been studied in electrocatalytic oxygen evolution reaction (OER), few studies have focused on the influence of regulating different crystal forms of MnO₂ on catalytic activity. This article prepared four different crystal forms of MnO₂ (α-MnO₂, β-MnO₂, γ-MnO₂ and δ-MnO₂), and systematically studied the catalytic performance of the catalyst (x-MnO₂-Ru) prepared by adding Ru to α-MnO₂, β-MnO₂, γ-MnO₂ and δ-MnO₂ for OER. The results of linear sweep voltammetry and chronopotentiometry measurements show that the catalyst prepared by adding Ru to β-MnO₂ (β-MnO₂-Ru) has the best electrochemical performance. β-MnO₂-Ru shows a low overpotential (300 mV at 10 mA·cm^-2) and outstanding catalytic activity with small degradation after 24 h operation. It is found that β-MnO₂-Ru exhibits excellent electrocatalytic performance due to its abundance of Mn³⁺and defect oxygen vacancies.

High Efficiency CO₂ Composite Absorbent Prepared by Modification of Carbide Slag

ZHANG Yuan, GAO Caiyun, LI Dong, LI Mei

2024, 53(2): 344-354.

Asbtract ( 44 )

PDF (24260KB) ( 28 )

References | Related Articles | Metrics

Carbide slag is a typical high calcium industrial solid waste with excellent CO₂ absorption performance, but the reaction activity and CO₂ absorption performance of pure carbide slag in calcium cycling will decrease with the increase of cycling times. Efficient and stable calcium-magnesium zinc composite absorbents was synthesized using carbide slag as the calcium source, MgO and ZnO as dopants. Effects of synthesis process conditions and doping amount on the absorption performance of CO₂ composite absorbent were investigated in a fixed bed reactor, as well as the changes in the internal structure of the absorbent during cyclic absorption. The results show that the absorbent synthesized by dry physical mixing method has a richer pore structure than wet mixing method. Mg and Zn elements are evenly dispersed on the surface of the carbide slag, effectively improving the anti-sintering performance and reaction activity of the carbide slag. The modified composite absorbent has higher CO₂ absorption performance during the cycling process, and after 20 cycles, CO₂ absorption capacity of the composite absorbent synthesized by dry physical mixing method can still reach 0.42 g/g.

Table of Content