Table of Content

15 July 2024, Volume 53 Issue 7

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Review

Applications of Flexible Transparent 2D Optoelectronic Devices in Intelligent Information Fields

LI Yang, CUI Nan, FU Nianqing, CHEN Youchen, PAN Shusheng, LIN Shenghuang

2024, 53(7):  1087-1105. 

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With the rapid development of novel smart electronics, there is an increasing demand for consumer electronic products that possess high performance, light weight and flexibility. However, traditional rigid silicon-based devices struggle to meet the specific requirements of fields such as wearable devices and electronic skins. Two-dimensional (2D) materials have garnered significant attention in the emerging electronics industry due to their excellent optoelectronic properties, making the flexible transparent 2D-based optoelectronic devices become a forefront research area in cutting-edge technology. This paper provides a detailed introduction to the key components of flexible transparent 2D optoelectronic devices, including 2D materials, transparent electrodes, and flexible transparent substrates/dielectric layers. It comprehensively discusses the wide-ranging applications of devices, such as flexible transparent transistors, photodetectors, sensors, and capacitors for wearable electronics, transparent smart displays, and medical monitoring. Finally, it summarizes the current challenges and development prospects of flexible transparent 2D optoelectronic devices. With the continuous innovation and development of materials science, nanotechnology, and manufacturing processes, it is believed that flexible transparent electronic technology will become more mature and reliable, bringing greater convenience and possibilities to human life.

Research Articles

Growth and Luminescence Properties of Large Size and High Quality CsCu₂I₃ Crystals

CHEN Xinxin, HAN Jiali, PAN Jianguo

2024, 53(7):  1106-1111. 

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The all-inorganic CsCu₂I₃ crystal was characterized by one-dimensional perovskite structure with orthorhombic crystal system and Cmcm space group, which was expected to be widely used in optoelectronic devices. In this paper, a transparent and high-quality CsCu₂I₃ single crystal with diameter of 1 inch (1 inch=2.54 cm) was grown by vertical Bridgman method, employing recrystallized CuI as the raw material. The phase structure and stability of the crystal were investigated by means of X-ray powder diffraction and thermogravimetric analysis. The optical and luminescence performance of the crystal was studied by means of ultraviolet-visible transmission spectroscopy, photoluminescence spectroscopy, fluorescence lifetime and fluorescence quantum yield. In addition, the variable temperature fluorescence spectra were measured at 100~250 K. The photoluminescence intensity decreases with increasing temperature due to strong electro-phonon coupling. The exciton binding energy (E_b) of the crystal is 98.12 meV. The study shows that the CsCu₂I₃ crystal exhibits good optical properties.

Investigation of Localized Cluster Structure and Spectral Properties of Er-Doped PbF₂ Crystals

LI Lin, ZHANG Peixiong, TAN Juncheng, ZHU Siqi, YIN Hao, LI Zhen, CHEN Zhenqiang

2024, 53(7):  1112-1120. 

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In this paper, a series of Er∶PbF₂ crystals were successfully grown by Bridgman method. The first-principles calculation based on the density functional theory was applied to investigate the clustering effect of Er³⁺ in PbF₂ crystals in details. The relationship between the up-conversion (UC) luminescence properties (luminescence intensity, color variation) and the cluster structure in Er∶PbF₂ crystals was obtained for the first time. It is found that as Er³⁺ concentration increases, the clusters evolve from monomers to higher-order configurations, with the distance between Er³⁺ ions decreasing and then increasing, resulting in the intensity of the red emission in the UC fluorescence first increasing and then decreasing, and the red-green luminescence ratio also decreases after the Er³⁺ concentration is higher than 6.5% (mole fraction), indicating that the luminescence color can be adjusted from red to yellow-green. This study proves that the structural evolution of rare-earth ion clusters could regulate the spectroscopic properties of Er∶PbF₂, which provides a novel method for the design of multi-color luminescent materials.

Growth and Optical Properties of Large Size CsCu₂I₃ Single Crystal by Solution Method

LING Hao, XU Le, CHEN Sixian, TANG Yuanzhi, SUN Haibin, GUO Xue, FENG Yurun, HU Qiangqiang

2024, 53(7):  1121-1126. 

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In recent years, copper-based perovskite has attracted widespread attention in the field of light emission and scintillation due to its excellent stability and environmental friendliness. However, most researches were focused on the 0D and 1D CsCu₂I₃ crystals, which limit the understanding for the intrinsic properties and anisotropy, as well as the practical application in scintillators. In this paper, a high-quality CsCu₂I₃ crystal with length of 5 mm was successfully grown by the solution cooling method. The crystal presents a transparent colorless appearance, with distinct edges and exposed facets. XRD results indicate that the CsCu₂I₃ crystal maintains good stability even after 6 months. The absorption spectrum shows an absorption peak of CsCu₂I₃ crystal at 310 nm. The band gap width is calculated to be 3.42 eV, indicating that the CsCu₂I₃ crystal is a wide-bandgap semiconductor. The emission wavelength of CsCu₂I₃ crystal is located at 580 nm, with full width at half maximum (FWHM) of 75 nm. The luminous chromaticity of the CsCu₂I₃ crystal falls at coordinates (0.47, 0.50) in the yellow region on the CIE chromaticity diagram, belonging to a warm white tone with color temperature of 3 000 K. It is consistent with its yellow emission of the CsCu₂I₃ crystal under the ultraviolet lamp. The fluorescence lifetime of the CsCu₂I₃ crystal is measured to be 51.6 and 215.5 ns.

Passively Q-Switched Er∶YAG Laser Based on Graphene Saturable Absorber

CHEN Yan, ZHANG Peixiong, QUAN Cong, SUN Dunlu, LI Zhen, CHEN Zhenqiang

2024, 53(7):  1127-1135. 

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In this paper, the Er∶YAG passively Q-switched laser using a xenon lamp side-pumping method and based on a graphene saturable absorber was investigated. Firstly, the graphene saturable absorber was successfully prepared by transferring graphene to the Al₂O₃ substrate, and its properties such as morphology, structure, and chemical state were characterized. In addition, the characteristics of the Er∶YAG passively Q-switched laser based on graphene saturable absorber were studied. The results show that the single pulse energy increases from 0.4 mJ to 7 mJ, the output laser single pulse width decreases from 761.2 ns to 510 ns, and the maximum peak power is 13.7 kW. The central wavelength of the laser is located at 2 935 and 2 945 nm, and the full width at half maximum (FWHM) corresponding to the main wavelength at 2 935 nm is 1.535 nm. The beam quality factors along the x and y directions are 4.45 and 5.76, respectively. This study provides an effective reference for developing lower cost 2.94 μm band Er∶YAG lasers with simple and compact resonant cavity designs.

Phase Field Study on Domain Structure Evolution of BaTiO₃ Nano Single Crystal Thin Films under Applied Electric Field

LI Haoqing, SU Yu

2024, 53(7):  1136-1149. 

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The frequency of the applied electric field and the epitaxial strain can affect the microstructure and the overall properties of ferroelectric thin films. In this study, the ferroelectric characteristics of BaTiO₃ nano single crystal thin films were investigated via phase field simulation under the epitaxial strain of -0.1% and -0.7%, respectively, in the frequency range of 0.1~100 kHz. It is found that, with the increase in frequency, the square-shaped hysteresis loop gradually changes to an elliptic loop and the butterfly loop changes to a kidney-shaped loop. When the applied frequency is below 50 kHz, the coercive field increases rapidly with the increase in frequency, but the change in remnant polarization is not significant. When the frequency is over 50 kHz, the coercive field only increases slightly, and the remnant polarization exhibits a downward trend. It is observed that the frequency dependence of ferroelectric properties is more significantly affected by the epitaxial strain while the frequency is low. The frequency dependence is not very sensitive to the epitaxial strain while the frequency is high. Meanwhile, the compressive epitaxial strain causes significant rise in both the remnant polarization and coercive field, and the tensile epitaxial strain leads to opposite effects. By analysis, it is found that the underlying mechanism of the frequency-dependent hysteresis is due to the competition between the speed of microstructure evolution and the frequency of the applied electric field. The findings of this study serve as theoretical basis for the experiment and design of ferroelectric functional thin films, and they provide knowledge-based support for the application of high-frequency electronic devices.

Preparation and Properties of ITO/AgNWs/ITO Films

YANG Tao, CHEN Caiming, HUANG Yujia, WU Shaoping, XU Huarui, WANG Kunzhe, ZHU Guisheng

2024, 53(7):  1150-1159. 

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With the advancement of display panel technology towards ultra-large size, ultra-high-definition and touch control capability, the traditional single indium tin oxide (ITO) film alone struggles to meet the increasingly demanding photoelectric performance requirements of display devices. Consequently, composite conductive films have been developed. This study fabricated an ITO(222)/AgNWs/ITO(400) composite film structure by embedding a two-dimensional silver nanowires (AgNWs) conductive networks into ITO films. The influences of the AgNWs addition and the sputtering temperature of the upper ITO film on the structural and optoelectronic properties of the composite film were systematically investigated. The AgNWs metal conductive networks not only enhance the electrical properties of the composite films but also maintain excellent optical characteristics. The results demonstrate that with a spin-coating of 600 μL AgNWs dispersion and a sputtering temperature of 175 ℃ for the upper ITO film, the fabricated composite ITO film has a sheet resistance of 7.13 Ω/□, an impressive transmittance of 91.52% at 550 nm, and a figure of merit of 57.82×10^-3 Ω^-1, achieving the preparation of a composite ITO film with ultra-low resistivity and high visible light transmittance.

Intermediate Shell Structure Regulation and Optical Properties of ZnSe Based Blue Quantum Dots

WU Shiting, YU Chunyan, FANG Jiaqing, XU Yang, ZHAI Guangmei

2024, 53(7):  1160-1169. 

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As a kind of heavy-metal-free wide bandgap quantum dots (QDs), ZnSe has received extensive attention in the field of blue quantum dots and its light-emitting diodes in recent years. However, there is usually a large lattice mismatch at the core-shell interface of ZnSe based blue quantum dots, where defect states can be easily formed to capture charge carriers and thus deteriorate their optical properties. In this work, ZnSeTe/ZnSe/ZnSeS/ZnS quantum dots with Se/S graded-composition ZnSeS intermediate shells in radial direction were synthesized by replacing the homogeneous single-layer ZnSeS shell with the graded-composition ZnSeS shells. X-ray diffraction, steady-state photoluminescence spectroscopy, time-resolved luminescence spectroscopy, transmission electron microscopy and electroluminescence measurement techniques were used to study the effects of the different intermediate shells on the structure, morphology and optical properties of the synthesized quantum dots. The results show that, all of the synthesized quantum dots emit deep blue light (444.5 nm) with narrow full widths at half maximum (<18 nm), and they also have uniform size and a zinc blende structure with high crystallinity. As the smoothness of the composition gradient in the ZnSeS intermediate shell along the radial direction is continuously improved, the optical properties such as photoluminescence quantum yield (PLQY) and color purity of the quantum dots are gradually enhanced. Among them, the quantum dots with the linearly graded ZnSeS shells formed by S atom diffusion have the narrowest full width at half maxium (15.8 nm) and the highest PLQY (20.7%). The maximum external quantum efficiency and brightness of the light-emitting diode device prepared using the quantum dots with optimal fluorescence performance as emitting materials are 1.8% and 750 cd/m², respectively. The quantum dot synthesis scheme and structural optimization strategy proposed in this study may contribute to the development of high-quality non-toxic blue ZnSe based core/shell quantum dots.

Synthesis and Luminescence Properties of Y₂MgTiO₆∶Eu³⁺ Red-Emitting Phosphor

JIANG Xiaokang, GAO Feng, ZHOU Hengwei

2024, 53(7):  1170-1176. 

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A series of novel red-emitting phosphors of Y_2-2xMgTiO₆∶2xEu³⁺(YMT∶2xEu³⁺,0≤x≤0.11) were synthesized by sol-gel method. Phase purity was examined by X-ray diffractometer (XRD) and the results show that the obtained YMT∶Eu³⁺ phosphors crystallize in the monoclinic space group P2₁/n and no other peaks are observed.The SEM images show that the obtained particles exhibit the non-uniform shapes with an average size of 2 μm. The photoluminescence spectrum under the excitation of 264 nm reveals four narrow bands at 591, 619, 657 and 698 nm, which correspond to the ⁵D₀→⁷F₁, ⁵D₀→⁷F₂, ⁵D₀→⁷F₃ and ⁵D₀→⁷F₄ transitions of Eu³⁺, respectively. The energy transfer mechanism among Eu³⁺ ions is identified as dipole-dipole (d-d) interactions.The phosphor of YMT∶0.14Eu³⁺ exhibits a chromaticity coordinates of (0.645, 0.332),which is close to the standard red color coordinates (0.67, 0.33).The temperature-dependent PL spectra were analyzed, and the calculated activation energy indicates the acceptable thermal stability of the phosphor. Hence, the red-emitting phosphors of YMT∶Eu³⁺ can be potentially applied to LED.

Bandgap Analysis and Optimization of Axisymmetric Low-Frequency Local Resonance Phononic Crystal

WANG Zhong, JIANG Jiao, SONG Yang, ZHANG Lei, GU Quan

2024, 53(7):  1177-1185. 

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This paper introduces a novel axisymmetric Helmholtz phononic crystal (AHPC) and conducts an in-depth investigation. A numerical model was developed to derive the complete bandgap of the AHPC structure, revealing the mechanism behind the formation of the bandgap, describing the characteristics of the sound pressure distribution at the edges of the bandgap, and confirming the low-frequency bandgap through experimentation, thereby validating the accuracy of the numerical model. The effects of neck length, neck width and cavity length on the low-frequency bandgap width and bandgap edge frequency were quantitatively investigated, identifying that these three parameters are the main factors affecting the bandgap distribution. Both the neck length and cavity length are positively correlated with the bandgap width and negatively correlated with the edge frequency of the bandgap, while the neck width shows a positive correlation with both bandgap width and edge frequency. Response surface analysis based on the Box-Behnken model was performed, and the functional relationships between the three factors and the bandgap width or the lower limit of the bandgap were obtained. Using these functional expressions, the structural parameters were optimized via the interior point method. The optimization results were verified by numerical simulation, and the optimal AHPC structure with a low-frequency bandgap ranging from 298.49 Hz to 519.27 Hz was obtained.

Effect of Electromagnetic Directional Solidification and Purification on Primary Silicon Enrichment Behavior in Al-50%Si Alloy

LIU Jiaxu, ZHANG Yintao, TANG Hong, CHEN Jiahui, CHEN Guangyu, HE Zhanwei, ZHAO Ziwei, GAO Mangmang

2024, 53(7):  1186-1195. 

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In the process of preparing polycrystalline silicon using Al-Si alloy purification, the enrichment of primary silicon can effectively reduce the consumption of aluminum and acid in the subsequent pickling process, thereby lowering the separation cost of high-purity primary silicon. Electromagnetic directional solidification is one of the best methods for preparing polycrystalline silicon currently due to its advantages such as simple process and strong controllability. However, there is a lack of systematic research on how various process parameters affect the enrichment of primary silicon. Therefore, this study investigates the effects of initial solidification temperature, crucible initial position, and descent rate on the behavior of primary silicon enrichment during the solidification process of Al-50%Si (mass fraction) alloy, and characterizes the morphology of primary silicon grains within the enrichment zone. The results show that when the initial solidification temperature is 950 ℃, the initial crucible position is -5 mm, and the crucible descent rate is 2 mm/h, primary silicon is mainly concentrated in the lower part of the ingot with a maximum enrichment rate of 79.1%, which is the optimal combination of processes. At the same time, as the degree of primary silicon enrichment increases, the primary silicon grains change from “disk-like” to coarse “spherical”, which helps reduce the inclusion of primary silicon and improve its purity.

Numerical Simulation of the Effect of Heat Shield Structure on Temperature Distribution in Growing 300 mm Semiconductor Grade Monocrystalline Silicon

NI Haoran, CHEN Ya, WANG Liguang, RUI Yang, ZHAO Zehui, MA Cheng, LIU Jie, ZHANG Xingmao, ZHAO Yanxiang, YANG Shaolin

2024, 53(7):  1196-1211. 

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Monocrystalline silicon is the fundamental material for chip manufacturing, and its quality depends not only on the control of impurity concentration but also on minimizing crystal defects. The density of native point defects in the crystal is one of the critical indicators for assessing the quality of the crystal, which requires optimization of the thermal field, adjustment of the temperature distribution during the crystal growth process, and precise control of the V/G ratio (the ratio of the pulling speed to the axial temperature gradient within the crystal). This study employs the finite volume method in ANSYS Fluent software to analyze the effect of different heat shield structures on the temperature distribution during the growth of 300 mm semiconductor-grade monocrystalline silicon by the Czochralski (Cz) process. Specifically, we investigated a two-piece heat shield design, altering the structure at different angles, and simulated the temperature distribution, axial temperature gradient at the solid-liquid interface, and V/G ratio at various stages of the pulling process (the initial stage at 400 mm, mid-stages at 800 and 1 400 mm, and the final stage at 2 000 mm). By analyzing the changes in V/G values across these stages, a heat shield structure with V/G values closer to the critical value ζ and better radial uniformity was found under relatively large temperature gradients, providing better conditions for reducing defect density. Additionally, by discussing the thermal history of the crystal rod, optimizing the heat shield structure to shorten the cooling cycle and providing better conditions for controlling the size of defects. The simulation results indicate that a heat shield structure with an included angle of 110°, a bottom thickness of 70 mm, and a gap of 30 mm between the inner wall of the heat shield and the crystal rod provides suitable temperature distribution conditions for the production of low-defect monocrystalline silicon.

Effect of Internal Radiation Heat Transfer on the Thermal Stress in Growing Ti∶Sapphire Crystal by Heat Exchanger Method

YU Hang, ZHAO Qi, QI Xiaofang, MA Wencheng, XU Yongkuan, HU Zhanggui

2024, 53(7):  1212-1221. 

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Titanium-doped sapphire crystal (Ti∶Al₂O₃, Ti∶sapphire) is the core material for the development of ultra-fast ultra-high-power laser systems. During the high-quality large-size Ti∶sapphire crystal growth process by heat exchanger method (HEM), internal radiation heat transfer has a significant impact on the heat transport, temperature and thermal stress distributions, and ultimately affects the crystal quality. Therefore, in this paper, the finite volume method is employed to simulate the internal radiation heat transfer within the Ti∶sapphire crystal and melt, while a displacement-based thermoelastic stress model is used to calculate the thermal stress in the crystal. The effects of internal radiation heat transfer on the temperature and thermal stress distributions were investigated in detail. The results show that internal radiation heat transfer significantly enhances the heat transport in the crystal and melt, resulting in dense distribution of isotherms at the bottom of the crystal and a significant increase of temperature gradient and thermal stress in this region. In addition, the thermal stress at the bottom of the crystal first increases and then decreases with the increase of the crystal absorption coefficient (doping concentration). As the absorption coefficient of the melt increases, the temperature gradient and thermal stress at the bottom of the crystal decrease slightly. As the scattering coefficient of the crystal increases, the temperature gradient and thermal stress at the bottom of the crystal gradually decrease. However, this influence is only important after the scattering coefficient is larger than the absorption coefficient.

First-Principles Study on Phase Transition Behavior of LiVO₃ under High Pressure

LENG Haoning, SUN Xiaoxiao, LIU Fengju, ZHAO Xiangmin

2024, 53(7):  1222-1230. 

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The structure, elastic properties and electronic properties of LiVO₃ within the pressure range of 0 to 90 GPa were discussed using first-principles calculation method based on density functional theory. The most stable structure of LiVO₃ at the ground state is C12/c1. When the pressure is between 0 GPa and 4.2 GPa, both C12/c1 and C1c1 structure co-exist. Under the pressure of 4.2 GPa, the material undergoes a structural phase transition from the C12/c1 phase to the R3cH phase. The bulk modulus, elastic modulus and shear modulus of LiVO₃ under zero pressure were calculated as 38, 23, 59 GPa, respectively, with a Poisson ratio of 0.24. The material is a non-central force solid, showing great ductility and great elastic anisotropy. The calculation of the electronic structure shows that the valence band top and conduction band bottom are mainly due to the covalent bonding between O and V. At the ground state, the C12/c1 structure of LiVO₃ is an indirect band-gap semiconductor with a band gap of 3.016 eV. The R3cH structure is also an indirect bandgap semiconductor with a band gap of 2.56 eV, which means that electrons are more prone to transition, significantly improving the electrical conductivity of the materials.

Investigation of the Physical Properties for Pnnm-CrB₄ under High Pressure

LEI Huiru, ZHANG Lihong

2024, 53(7):  1231-1238. 

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The crystal structure and elastic properties of chromium tetraboride (CrB₄) were investigated by pseudopotential plane-wave methods within the Perdew-Burke-Ernzerhof (PBE) form of generalized gradient approximation (GGA). The calculated equilibrium structural parameters of Pnnm-CrB₄ are in good agreement with the available experimental data and other theoretical results. Moreover, the elastic constants C_ij, bulk modulus B, shear modulus G and elastic modulus E under high pressure were calculated, and the toughness and brittleness of Pnnm-CrB₄ under high pressure were analyzed with the Poisson ratio σ and B/G. To study the elastic anisotropy of Pnnm-CrB₄ in detail, the anisotropic factors A₁,A₂,A₃ for shear and B_a, B_b, B_c for the directional bulk modulus were also calculated. The Vickers hardness H_V of Pnnm-CrB₄ was estimated at the same time. Finally, the total and partial density of states of Pnnm-CrB₄ under high pressure were studied so as to have a better understanding of the mechanical and elastic properties of Pnnm-CrB₄.

First-Principles Study on Electronic Structure and Optical Properties of SnO₂ (110)/FAPbBrI₂ (001) Interface

LI Lihua, ZHOU Longjie, LIU Shuo, WANG Hang, HUANG Jinliang

2024, 53(7):  1239-1248. 

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The electronic structure and optical properties of SnO₂(110)/FAPbBrI₂(001) interface were studied using first-principles based on density functional theory (DFT). FAPbBrI₂ is a direct bandgap semiconductor material with a bandgap value of 1.58 eV. By constructing a model of the interface between SnO₂(110) and FAPbBrI₂(001), the lattice mismatch is found to be 4.28%, and the interface binding energy is -0.116 eV/Ų, indicating the stability of this interface structure. Through the analysis of the density of states (DOS) of SnO₂(110)/FAPbBrI₂(001) interface, it was discovered that interface states primarily originated from hybridization of O 2p, I 5p, Br 4p, and Pb 6p orbital electrons at the interface. Charge density difference and Bader charge analysis reveal significant charge transfer at the interface, promoting bonding between the interface atoms and enhancing interface stability. And effective charge separation led to a significant improvement in the absorption coefficient of the SnO₂(110)/FAPbBrI₂(001) interface compared to the surfaces of SnO₂(110) and FAPbBrI₂(001).

First-Principles Study on Electronic Structure and Optical Properties of Zn-Doped Boron Nitride

HE Zhihao, GOU Jie, WANG Yunjie, QI Yajie, DING Jiafu, ZHANG Bo, ZHAO Xingsheng, PEI Yizhen, HOU Shuyu, SU Xin

2024, 53(7):  1249-1256. 

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In this paper, the electronic structure and optical properties of BN doped with different concentrations of Zn (0.062 5, 0.125, 0.25) were investigated based on the density functional theory. The results show that the defect formation energies of the three systems after doping are all greater than zero, for this reason the stresses are also calculated which verifies that all of them can exist stably. B_1-xZn_xN (x=0, 0.062 5, 0.125) is a direct bandgap semiconductor and B_0.75Zn_0.25N is an indirect bandgap semiconductor. The bandgap of the system gradually decreases with increasing doping concentration. The doping of Zn leads to the introduction of a receptor energy level near the Fermi level, resulting in the valence band being shifted up above the Fermi level, and the doped systems were all characterized by p-type semiconductor properties. With increasing doping concentration, the static permittivity of the systems gradually increases, the peak of the imaginary part of the doped system gradually decreases, and the value of the corresponding reflectivity at the highest peak gradually becomes smaller. In the low energy region, the doped systems all enhance the absorption of light and the absorption edge red shift. The bond strengths of B—N and N—Zn bonds in the doped systems gradually increase. To sum up, it can be concluded that doping Zn atoms can effectively improve the electronic structure as well as the optical properties of BN.

Synthesis, Crystal Structure and Antitumor Activity of 6-Fluoro-4-Hydroxy-3-Oxo-3,4-Dihydroquinoxaline-1 (2H)-Carboxylic Acid Tert-Butyl Ester

MAO Yunhong, ZHAO Chunshen

2024, 53(7):  1257-1268. 

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Quinoxaline compounds are widely used in the fields of medicine and chemical industry, especially in the development of anticancer drugs, due to their significant biological activity. 6-fluoro-4-hydroxy-3-oxo-3,4-dihydroquinoline-1 (2H)-carboxylic acid tert-butyl ester was synthesized through a four-step reaction method in this paper, and its single crystal was obtained by solution crystallization method. Crystallographic analysis indicates that the compound belongs to monoclinic crystal system with space group C2/c, the unit cell dimensions are a=1.286 63(10) nm, b=2.252 49(17) nm, c=1.015 64(7) nm, Z=8, ρ_c=1.359 g·cm^-3, R=0.053 8, R_w=0.140 6. The optimal structure was calculated using density functional theory (DFT) in B3LYP/6-311+G (2d, p) mode. The results are basically consistent with those obtained by X-ray single crystal diffraction. The antitumor activity study shows that the compound has good antitumor effect. In addition, the electrostatic potential and frontier molecular orbitals of the molecules were calculated by DFT to further understand their physical and chemical properties.

Preparation of B and N Co-Doped Carbon Micro-Nanostructures Using Waste Coconut Wood and Their Electromagnetic Wave Absorption Properties

FAN Hao, CHEN Yongjun, LI Jianbao, CHEN Shuaifeng, CHEN Qing

2024, 53(7):  1269-1279. 

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5G communication technology provides great convenience for social development and daily life, but it also brings serious electromagnetic wave pollution. To mitigate the harm caused by this pollution, designing lightweight and eco-friendly broadband electromagnetic wave absorbing materials has become a research focus. In this paper, a B and N co-doped carbon material with bamboo-like one-dimensional hollow tubular structure is prepared using coconut wood as precursor. B and N co-doping optimizes the composition of biomass-derived carbon and improves the impedance matching of the material. The bamboo-like one-dimensional hollow tubular structure is conducive to the entry of electromagnetic waves into the material. Consequently, the prepared material exhibits remarkable electromagnetic wave absorption properties, with the lowest reflection loss (RL) value of -59.64 dB at 14.12 GHz, an effective absorption bandwidth (EAB) width range of 5.88 GHz, and a required thickness of only 2.1 mm. Research results demonstrate that the excellent electromagnetic wave absorption performance of this material stems from a combination of multiple refractions and scattering within the material, dipolar polarization, interfacial polarization, and conductive polarization.

Electrochemical Properties of Ni-Doped Polyaniline/Biomass Carbon Composites

ZHANG Dandan, TIAN Manze, YAN Bo, REN Junpeng, ZHOU Jinkang

2024, 53(7):  1280-1287. 

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In order to prepare high-performance and low-cost electrode materials, nickel ion-doped polyANI-coated biomass carbon composite materials (Ni@PANI/BC) were synthesized by chemical oxidation polymerization using August melon peel biomass carbon (BC) as the matrix, and nickel nitrate and aniline as raw materials. The structures of the Ni@PANI/BC composites were characterized by SEM, EDS, X-ray photoelectron energy spectrum (XPS), thermal weight analysis (TG) and specific surface area test (BET), and the electrochemical properties of the composites were measured by cyclic voltammetry (CV), constant current charge and discharge (GCD) test and electrochemical impedance spectroscopy (EIS). The effects of nickel ion doping on the structure and electrochemical properties of Ni@PANI/BC were investigated. It is shown that nickel ion doped BC forms a porous cross-linked mesh porous structure with large specific surface area and good electrical conductivity. When the mass ratio of nickel hydrate nitrate, aniline and BC is 1.5∶5∶3, the obtained electrode material has the best electrochemical performance. At 1 A/g current density, Ni@PANI/BC mass capacitance is up to 608.4 F/g, 5 000 cycles with a capacity retention rate of 85.4%, which demonstrates Ni@PANI/BC materials have electrochemical properties comparable to the relevant materials reported in the literature.