检索结果-内蒙古大学图书馆

BN/SiC Coating on SiC Tows Prepared by Chemical Vapor Infiltration

IOP Conference Series: Materials science and engineering 2019年第1期678卷

作者： Zhe Qi Xiaoxu Lv Wenqing Zhao Shizhen Zhu Jian Jiao National Key Laboratory of Advanced Composites AECC Beijing Institute of Aeronautical Materials Beijing 100095 China Surface Engineering Division AECC Beijing Institute of Aeronautical Materials Beijing 100095 China School of Materials Science and Engineering Beijing Institute of Technology Beijing 100082 China

Boron nitride (BN) and silicon carbide (SiC) coatings were prepared in sequence on desized SiC tows by chemical vapor infiltration (CVI) at the temperature of 950°C. BN was synthesized by the reaction between boron trichloride (BCl3) and ammonia (NH3) while SiC was from the thermal decomposition of methyl trichlorosilane (MTS). The thickness of the coatings was uniform on a certain cross section of a monofilament, and the thickest/thinnest ratio is less than ~2 across the whole SiC tows for both SiC and BN coatings, as observed by scanning electron microscopy (SEM). Distinct β-SiC powder X-ray diffraction (XRD) pattern was obtained for as-prepared CVI SiC while as-prepared BN coating only showed a bump and a tiny peak corresponding to hexagonal BN (h-BN). This result was verified by transmission electron microscopy (TEM) images, in which CVI BN only had curved diffraction fringes within small pockets, known as turbostractic structures(t-BN). However, t-BN possesses similar short-range structure to h-BN as demonstrated by 11B solid-state NMR spectrum. SiCf/SiC minicomposites using the interphase coating mentioned above is currently under investigation.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Evidence for a Z2 topological ordered quantum spin liquid in a kagome-lattice antiferromagnet

arXiv

引用

arXiv 2017年

作者： Wei, Yuan Feng, Zili Lohstroh, Wiebke Yu, D.H. dela Cruz, Clarina Yi, Wei Ding, Z.F. Zhang, J. Tan, Cheng Shu, Lei Wang, Yan-Cheng Wu, Han-Qing Luo, Jianlin Mei, Jia-Wei Meng, Zi Yang Shi, Youguo Li, Shiliang Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China School of Physical Sciences University of Chinese Academy of Sciences Beijing100190 China Technische Universität München Garching D-85747 Germany Australian Nuclear Science and Technology Organization Lucas HeightsNSW2232 Australia Neutron Scattering Division Neutron Sciences Directorate Oak Ridge National Laboratory Oak RidgeTN37831 United States Semiconductor Device Materials Group National Institute for Materials Science 1-1 Namiki Tsukuba Ibaraki305-0044 Japan State Key Laboratory of Surface Physics Department of Physics Fudan University Shanghai200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing210093 China School of Physics Sun Yat-Sen University Guangzhou510275 China Songshan Lake Materials Laboratory Dongguan Guangdong523808 China Institute for Quantum Science and Engineering Department of Physics Southern University of Science and Technology Shenzhen518055 China Center of Materials Science andOptoelectronicsEngineeringUniversity of Chinese Academy of Sciences Beijing100049 China

A quantum spin liquid with a Z2 topological order has long been thought to be important for the application of quantum computing and may be related to high-temperature superconductivity [1–3]. While a two-dimensional kagome antiferromagnet may host such a state, strong experimental evidences are still lacking [4–9]. Here we show that the spin excitations from the kagome planes in magnetically ordered Cu4(OD)6FBr and non-magnetically ordered Cu3Zn(OD)6FBr are similarly gapped although the content of inter-kagome-layer Cu2+ ions changes dramatically. This suggests that the spin triplet gap and continuum of the intrinsic kagome antiferromagnet are robust against the interlayer magnetic impurities. Our results show that the ground state of Cu3Zn(OD)6FBr is a gapped quantum spin liquid with Z2 topological order. Copyright © 2017, The Authors. All rights reserved.

关键词： Ground state

来源：评论

学校读者我要写书评

暂无评论

The microstructure and mechanical properties of silicon carbide fibers with boron nitride interphase

引用

IOP Conference Series: Materials science and engineering 2019年第1期678卷

作者： Xiaoxu Lv Zhe Qi Zhuoyu Jiang Yiran Zhou Wenqing Zhao Jian Jiao National Key Laboratory of Advanced Composites AECC Beijing Institute of Aeronautical Materials Beijing 100095 China Surface Engineering Division AECC Beijing Institute of Aeronautical Materials Beijing 100095 China School of Materials Science and Engineering Beijing Institute of Technology Beijing 100082 China

The 2nd generation SiC tows is a type of essentially polycrystalline fibers (SiC1.46O0.03). Smooth and uniform boron nitride interphase was deposited on SiC fibers by low pressure chemical vapor infiltration (CVI). The scanning electron microscopy(SEM) was used to characterize the microstructure of the BN interphase and fibers while X-ray diffraction(XRD) and TEM were used to characterize the phase constitute of the fibers. The XRD and TEM results showed that the BN interphase prepared by CVI is turbostratic. The effects of thickness on the mechanical properties of SiC fibers were investigated by using two-parameter Weibull distribution. The fibers with thin BN interphase showed higher strength than the as-received fibers, for healing the surface flaws. However, the soft nature of increasing BN thickness had a more dominant effect and resulted in the decrease of fiber strength.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Machine-Learning Modeling for Ultra-Stable High-Efficiency Perovskite Solar Cells

引用

advanced Energy Materials 2022年第41期12卷

作者： Yingjie Hu Xiaobing Hu Lu Zhang Tao Zheng Jiaxue You Binxia Jia Yabin Ma Xinyi Du Lei Zhang Jincheng Wang Bo Che Tao Chen Shengzhong (Frank) Liu Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education Shaanxi Key Laboratory for Advanced Energy Devices Shaanxi Engineering Lab for Advanced Energy Technology Institute for Advanced Energy Materials School of Materials Science and Engineering Shaanxi Normal University Xi'an 710119 China State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an 710072 China School of Chemistry and Materials Science Nanjing University of Information Science & Technology Nanjing 210044 China National Research Center for Physical Sciences at the Microscale CAS Key Laboratory of Materials for Energy Conversion School of Chemistry and Materials Science University of Science and Technology of China Hefei 230026 China Dalian National Laboratory for Clean Energy iChEM Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China University of the Chinese Academy of Sciences Beijing 100039 China

Understanding the key factor driving the efficiency and stability of semiconductor devices is vital. To date, the key factor influencing the long-term stability of perovskite solar cells (PSCs) remains unknown because of the many influencing factors. In this work, through machine learning, the influences of five factors, including grain size, defect density, bandgap, fluorescence lifetime, and surface roughness, on the efficiency and stability of PSCs have been revealed. It is found that the bandgap has the greatest influence on the efficiency, and the surface roughness and grain size are most influential to the long-term stability. A mathematical model is given to predict efficiency based on fluorescence lifetime and bandgap. Guided by the model, four groups of experiments are conducted to confirm the machine-learning predictions and a PSC with 23.4% efficiency and excellent long-term stability is obtained, as manifested by retention of 97.6% of the initial efficiency after 3288 h aging in the ambient environment, the best stability under these conditions. This work shows that machine learning is an effective means to enrich semiconductor physical models.

关键词： high efficiency machine learning perovskite solar cells stability surface polarization

来源：评论

学校读者我要写书评

暂无评论

Synergy of Photogenerated Electrons and Holes toward Efficient Photocatalytic Urea Synthesis from CO2and N2

引用

Angewandte Chemie 2024年第32期136卷

作者： Yida Zhang Dr. Yingjie Sun Qingyu Wang Dr. Zechao Zhuang Zhentao Ma Limin Liu Prof. Gongming Wang Prof. Dingsheng Wang Prof. Xusheng Zheng National Synchrotron Radiation Laboratory University of Science and Technology of China Anhui 230029 China College of Chemistry and Materials Science University of Science and Technology of China Anhui 230026 China Hebei Key Laboratory of Photoelectric Control on Surface and Interface College of Science Hebei University of Science and Technology Hebei 050018 China Engineering Research Center of Advanced Rare Earth Materials Department of Chemistry Tsinghua University Beijing 100084 China

Directly coupling N 2 and CO 2 to synthesize urea by photocatalysis paves a sustainable route for urea synthesis, but its performance is limited by the competition of photogenerated electrons between N 2 and CO 2 , as well as the underutilized photogenerated holes. Herein, we report an efficient urea synthesis process involving photogenerated electrons and holes in respectively converting CO 2 and N 2 over a redox heterojunction consisting of WO 3 and Ni single-atom-decorated CdS (Ni 1 -CdS/WO 3 ). For the photocatalytic urea synthesis from N 2 and CO 2 in pure water, Ni 1 -CdS/WO 3 attained a urea yield rate of 78 μM h −1 and an apparent quantum yield of 0.15 % at 385 nm, which ranked among the best photocatalytic urea synthesis performance reported. Mechanistic studies reveal that the N 2 was converted into NO species by ⋅OH radicals generated from photogenerated holes over the WO 3 component, meanwhile, the CO 2 was transformed into *CO species over the Ni site by photogenerated electrons. The generated NO and *CO species were further coupled to form *OCNO intermediate, then gradually transformed into urea. This work emphasizes the importance of reasonably utilizing photogenerated holes in photocatalytic reduction reactions.

关键词： urea synthesis nitrogen carbon dioxide photogenerated holes Ni single atoms

来源：评论

学校读者我要写书评

暂无评论

Dynamic Passivation of Perovskite Films via Gradual Additive Release for Enhanced Solar Cell Efficiency

引用

Angewandte Chemie 2024年第11期137卷

作者： Yujie Zhu Jing Zhang Hang Su Peijun Wang Yutong She Xinxin Zheng Xin Liu Jiarong Wu Runkang Wang Ying Wang Deng Li Shengzhong Frank Liu Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education Shaanxi Key Laboratory for Advanced Energy Devices Shaanxi Engineering Lab for Advanced Energy Technology School of Materials Science and Engineering Shaanxi Normal University Xi'an 710119 China School of Science Xi'an University of Posts & Telecommunications Xi'an 710121 China Key Laboratory of Photoelectric Conversion and Utilization of Solar Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China

Modifying perovskites with functional additives has proven effective in refining the crystallization process and passivating the defects of perovskite films, thereby ensuring high photovoltaic efficiencies. However, conventional methods that involve pre-mixing additives into the precursor solution often face challenges due to discrepancies in the spatial distribution of slow-diffused additives relative to dynamically formed defect sites, resulting in limited passivation effectiveness. To address this issue, this study innovatively proposes a dynamic passivation strategy that utilizes a pre-passivator to gradually release active additives during the thermal crystallization process of perovskite films. By leveraging the principle of energy minimization, these timely-released additives can interact precisely and selectively with the high-energy defect sites generated during crystallization, thus facilitating efficient additive utilization and in situ real-time defect passivation. Through analysis of crystallization kinetics and carrier dynamic, it is demonstrated that this dynamic passivation approach significantly improves film quality and prolongs carrier lifetime, outperforming traditional pre-mixing tactics. Consequently, the final perovskite solar cell achieves an impressive solar conversion efficiency of 25.33 %, along with exceptional stability. This work provides strong support of tailored additive strategies aimed at further enhancing the efficiency of perovskite solar cells and their subsequent commercial applications.

关键词： perovskites dynamic passivation pre-passivator defects crystallization

来源：评论

学校读者我要写书评

暂无评论

Molecular Bridge on Buried Interface for Efficient and Stable Perovskite Solar Cells

引用

Angewandte Chemie 2023年第34期135卷

作者： Dr. Haodan Guo Prof. Wanchun Xiang Dr. Yanyan Fang Prof. Jingrui Li Prof. Yuan Lin Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education Shaanxi Key Laboratory for Advanced Energy Devices Shaanxi Engineering Lab for Advanced Energy Technology School of Materials Science and Engineering Shaanxi Normal University Xi'an 710119 China CAS Key Laboratory of Photochemistry CAS Research/Education Center for Excellence in Molecular Sciences Beijing National Laboratory for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China School of Electronic Science and Engineering Xi'an Jiaotong University Xi'an 710049 China

The interface of perovskite solar cells (PSCs) is significantly important for charge transfer and device stability, while the buried interface with the impact on perovskite film growth has been paid less attention. Herein, we use a molecular modifier, glycocyamine (GDA) to build a molecular bridge on the buried interface of SnO 2 /perovskite, resulting in superior interfacial contact. This is achieved through the strongly interaction between GDA and SnO 2 , which also appreciably modulates the energy level. Moreover, GDA can regulate the perovskite crystal growth, yielding perovskite film with enlarged grain size and absence of pinholes, exhibiting substantially reduced defect density. Consequently, PSCs with GDA modification demonstrate significant improvement of open circuit voltage (close to 1.2 V) and fill factor, leading to an improved power conversion efficiency from 22.60 % to 24.70 %. Additionally, stabilities of GDA devices under maximum power point and 85 °C heat both perform better than the control devices.

关键词： Buried Interface Molecular Bridge Molecular Modifier Perovskite Solar Cells

来源：评论

学校读者我要写书评

暂无评论

Polydentate Ligand Reinforced Chelating to Stabilize Buried Interface toward High-Performance Perovskite Solar Cells

引用

Angewandte Chemie 2024年第8期136卷

作者： Baibai Liu Qian Zhou Yong Li Yu Chen Dongmei He Danqing Ma Xiao Han Ru Li Ke Yang Yingguo Yang Shirong Lu Xiaodong Ren Zhengfu Zhang Liming Ding Jing Feng Jianhong Yi Jiangzhao Chen Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education) College of Optoelectronic Engineering Chongqing University Chongqing 400044 China Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education Shaanxi Key Laboratory for Advanced Energy Devices Shaanxi Engineering Lab for Advanced Energy Technology Institute for Advanced Energy Materials School of Materials Science and Engineering Shaanxi Normal University Xi'an 710119 China Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences Chongqing 400714 China School of Microelectronics Fudan University Shanghai 200433 China Department of Material Science and Technology Taizhou University Taizhou 318000 China Yunnan Key Laboratory for Micro/Nano Materials & Technology International Joint Research Center for Optoelectronic and Energy Materials School of Materials and Energy Yunnan University Kunming 650091 China Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming 650093 China Center for Excellence in Nanoscience (CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS) National Center for Nanoscience and Technology Beijing 100190 China

The instability of the buried interface poses a serious challenge for commercializing perovskite photovoltaic technology. Herein, we report a polydentate ligand reinforced chelating strategy to strengthen the stability of buried interface by managing interfacial defects and stress. The bis(2,2,2-trifluoroethyl) (methoxycarbonylmethyl)phosphonate (BTP) is employed to manipulate the buried interface. The C=O, P=O and two −CF 3 functional groups in BTP synergistically passivate the defects from the surface of SnO 2 and the bottom surface of the perovskite layer. Moreover, The BTP modification contributes to mitigated interfacial residual tensile stress, promoted perovskite crystallization, and reduced interfacial energy barrier. The multidentate ligand modulation strategy is appropriate for different perovskite compositions. Due to much reduced nonradiative recombination and heightened interface contact, the device with BTP yields a promising power conversion efficiency (PCE) of 24.63 %, which is one of the highest efficiencies ever reported for devices fabricated in the air environment. The unencapsulated BTP-modified devices degrade to 98.6 % and 84.2 % of their initial PCE values after over 3000 h of aging in the ambient environment and after 1728 h of thermal stress, respectively. This work provides insights into strengthening the stability of the buried interface by engineering multidentate chelating ligand molecules.

关键词： Buried Interface Chelating Perovskite Polydentate Ligand Solar Cells

来源：评论

学校读者我要写书评

暂无评论

Roadmap on Perovskite Light-Emitting Diodes

arXiv

引用

arXiv 2023年

作者： Chen, Ziming Hoye, Robert L.Z. Yip, Hin-Lap Fiuza-Maneiro, Nadesh López-Fernández, Iago Otero-Martínez, Clara Polavarapu, Lakshminarayana Mondal, Navendu Mirabelli, Alessandro Anaya, Miguel Stranks, Samuel D. Liu, Hui Shi, Guangyi Xiao, Zhengguo Kim, Nakyung Kim, Yunna Shin, Byungha Shi, Jinquan Liu, Mengxia Zhang, Qianpeng Fan, Zhiyong Loy, James C. Zhao, Lianfeng Rand, Barry P. Arfin, Habibul Saikia, Sajid Nag, Angshuman Zou, Chen Lin, Lih Y. Xiang, Hengyang Zeng, Haibo Liu, Denghui Su, Shi-Jian Wang, Chenhui Zhong, Haizheng Xuan, Tong-Tong Xie, Rong-Jun Bao, Chunxiong Gao, Feng Gao, Xiang Qin, Chuanjiang Kim, Young-Hoon Beard, Matthew C. Department of Chemistry Centre for Processible Electronics Imperial College London LondonW12 0BZ United Kingdom Inorganic Chemistry Laboratory Department of Chemistry University of Oxford South Parks Road OxfordOX1 3QR United Kingdom Department of Materials Imperial College London Exhibition Road LondonSW7 2AZ United Kingdom Department of Materials Science and Engineering City University of Hong Kong Hong Kong Hong Kong School of Energy and Environment City University of Hong Kong Hong Kong Hong Kong CINBIO Universidade de Vigo Materials Chemistry and Physics Group Department of Physical Chemistry Campus Universitario As Lagoas Marcosende Vigo36310 Spain Department of Chemical Engineering and Biotechnology University of Cambridge CambridgeCB3 0AS United Kingdom Department of Physics CAS Key Laboratory of Strongly Coupled Quantum Matter Physics University of Science and Technology of China Anhui Hefei230026 China Daejeon34141 Korea Republic of Department of Electrical Engineering Yale University New HavenCT06511 United States Energy Sciences Institute Yale University West HavenCT06516 United States Department of Electronic & Computer Engineering The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong Hong Kong Department of Physics Princeton University PrincetonNJ08544 United States Department of Electrical and Computer Engineering Princeton University PrincetonNJ08544 United States Andlinger Center for Energy and the Environment Princeton University PrincetonNJ08544 United States Pune411008 India Zhejiang University Zhejiang Hangzhou310058 China University of Washington SeattleWA98195 United States MIIT Key Laboratory of Advanced Display Materials and Devices Institute of Optoelectronics & Nanomaterials College of Materials Science and Engineering Nanjing University of Science and Technology Nanjing210094 China State Key Laboratory of Luminescent Materials and Devices Institute of Polymer Opto

In recent years, the field of metal-halide perovskite emitters has rapidly emerged as a new community in solid-state lighting. Their exceptional optoelectronic properties have contributed to the rapid rise in external... 详细信息

关键词： Perovskite

来源：评论

学校读者我要写书评

暂无评论

Precise Synthesis of Dual-Single-Atom Electrocatalysts through Pre-Coordination-Directed in Situ Confinement for CO2Reduction

引用

Angewandte Chemie 2024年第3期137卷

作者： Peng Rao Xingqi Han Haochen Sun Fangyuan Wang Ying Liang Jing Li Daoxiong Wu Xiaodong Shi Zhenye Kang Zhengpei Miao Peilin Deng Xinlong Tian School of Marine Science and Engineering Hainan University Haikou 570228 China State Key Laboratory for Modification of Chemical Fibers and Polymer Materials Center for Advanced Low-dimension Materials/Innovation Center for Textile Science and Technology/Institute of Functional Materials/Center for Civil Aviation Composites College of Materials Science and Engineering Donghua University Shanghai 201620 China

Dual-single-atom catalysts (DSACs) are the next paradigm shift in single-atom catalysts because of the enhanced performance brought about by the synergistic effects between adjacent bimetallic pairs. However, there are few methods for synthesizing DSACs with precise bimetallic structures. Herein, a pre-coordination strategy is proposed to precisely synthesize a library of DSACs. This strategy ensures the selective and effective coordination of two metals via phthalocyanines with specific coordination sites, such as −F− and −OH−. Subsequently, in situ confinement inhibits the migration of metal pairs during high-temperature pyrolysis, and obtains the DSACs with precisely constructed metal pairs. Despite changing synthetic parameters, including transition metal centers, metal pairs, and spatial geometry, the products exhibit similar atomic metal pairs dispersion properties, demonstrating the universality of the strategy. The pre-coordination strategy synthesized DSACs shows significant CO 2 reduction reaction performance in both flow-cell and practical rechargeable Zn-CO 2 batteries. This work not only provides new insights into the precise synthesis of DSACs, but also offers guidelines for the accelerated discovery of efficient catalysts.

关键词： Dual-single-atom catalysts bimetallic pairs pre-coordination strategy CO2 reduction reaction synergistic effects

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：