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Fast growth of cerium-doped lutetium yttrium orthosilicate single crystals and their scintillation properties

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Journal of Rare Earths 2021年第12期39卷 1527-1532,I0003页

作者： Kunfeng Chen dongfeng xue State Key Laboratory of Crystal Materials Institute of Crystal MaterialsShandong UniversityJi'nan 250100China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesShenzhen 518055China Multiscale Crystal Materials Research Center Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesChangchun 130022China

The growth of high-quality and large-size cerium-doped lutetium yttrium orthosilicate(Ce:(LuY)2 SiO5,Ce:LYSO)crystals with lower cost has great influence on their applications in various physical *** to the chemical bonding theory of single crystal growth,the fast thermodynamic growth direction of Ce:LYSO is[010]*** this work,the maximum pulling rate of 3.5 mm/h is obtained along[010]direction of Ce:LYSO via the Czochralski(Cz)***,Ce:LYSO bulk single crystals with diameter of 64 mm and length of 220 mm and mass of 4.2 kg are *** luminescence performance of low-doped Ce:LYSO for nuclear irradiation(^(22)Na)detector device was *** yield of26193 ph/MeV and decay time of 38 ns are *** present work provides a promising fast growth approach to achieving large size functional bulk crystal via both thermodynamic and kinetic controls.

关键词： Crystal growth LYSO Czochralski method Chemical bonding theory Inorganic scintillator Rare earths

Electrochemical energy storage applications of “pristine” graphene produced by non-oxidative routes

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Science China(Technological Sciences) 2015年第11期58卷 1841-1850页

作者： LIU Fei xue dongfeng State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences

Graphene is a promising material as both active components and additives in electrochemical energy storage devices. The properties of graphene strongly depend on the fabrication methods. The applications of reduced graphene oxide as electrode materials have been well studied and reviewed, but the using of "pristine" graphene as electrode material for energy storage is still a new topic. In this paper, we review state-of-the-art progress in the fabrication of "pristine" graphene by different methods and the electrochemical performance of graphene-based electrodes. The achievements in this area will be summarized and compared with the graphene oxide route in terms of cost, scalability, material properties and performances, and the challenges in these methods will be discussed as well.

关键词： pristine graphene energy storage exfoliation electrochemical

Rare earth and transitional metal colloidal supercapacitors

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Science China(Technological Sciences) 2015年第11期58卷 1768-1778页

作者： CHEN KunFeng xue dongfeng State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences

The search of electrode materials with high electrochemical activity is one of key solutions to actualize both high energy density and high power density in a supercapacitor. Recently, we have developed one novel kind of rare earth and transitional metal colloidal supercapacitors, which can deliver higher specific capacitance than electrical double-layer capacitors(EDLC) and traditional pseudocapacitors. The electrode materials in colloidal supercapacitors are in-situ formed electroactive colloids, which were transformed from commercial rare earth and transitional metal salts in alkaline electrolyte by chemical and electrochemical assisted coprecipitation. In these colloidal supercapacitors, multiple-electron Faradaic redox reactions can be utilized, which can deliver ultrahigh specific capacitance often larger than one-electron capacitance. Multiple-valence metal cations used in our designed colloidal supercapacitors mainly include Ce3+, Yb3+, Er3+, Fe3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Sn2+ and Sn4+. The colloidal supercapacitors can be served as the promising next-generation high performance supercapacitors.

关键词： supercapacitor colloidal electrode electroactive cation rare earth cation transitional metal cation

Pulling growth technique towards rare earth single crystals

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Science China(Technological Sciences) 2018年第9期61卷 1295-1300页

作者： SUN CongTing xue dongfeng State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences

Pulling growth technique serves as a popular method to grow congruent melting single crystals with multiscale sizes ranging from micrometers to *** order to obtain high quality single crystals,the crystal constituents would be arranged at the lattice sites by precisely controlling the crystal growth *** interface is the position where the phase transition of crystal constituents occurs during pulling growth *** precise control of energy at the growing interface becomes a key technique in pulling *** this work,we review some recent advances of pulling technique towards rare earth single crystal *** Czochralski pulling growth,the optimized growth parameters were designed for rare earth ions doped Y_3Al_5O_(12)and Ce:(Lu_(1-x)Y_x)_2Si O_5on the basis of anisotropic chemical bonding and isotropic mass transfer calculations at the growing *** fast growth of high quality rare earth single crystals is realized by controlling crystallization thermodynamics and kinetics in different size *** the other hand,the micro pulling down technique can be used for high throughput screening novel rare earth optical *** growth interface control is realized by improving the crucible bottom and temperature field,which favors the growth of rare earth crystal *** rare earth laser crystal fiber can serve as another kind of laser gain medium between conventional bulk single crystal and glass *** future work on pulling technique might focus on the mass production of rare earth single crystals with extreme size and with the size near that of devices.

关键词： pulling growth technique rare earth single crystals Czochralski pulling growth, micro pulling down growth Y3Al5O12 Ce:(Lu1-xYx)2SiO5 chemical bonding theory of single crystal growth

4f chemistry towards rare earth materials science and engineering

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Science China(Technological Sciences) 2017年第11期60卷 1767-1768页

作者： xue dongfeng SUN CongTing State Key Laboratory of Rare Earth Resouree Utilization Changchun Institute of Applied ChemistryChinese Academy of ScieneesChangchun 130022China

The big challenge in rare earth （RE） resource utilization is to effectively manage their balanced use and advanced applica- tions of 17 elements （Sc, Y and La-Lu） [ 1,2]. As a family, RE materials possess outstanding optical, electronic, and mag- netic properties owing to the unique valence electron structure of RE elements, especially the 4felectrons [3]. With in- creasing demands of modern applications, the development of novel RE materials becomes an unceasing topic. The application window of RE materials is mainly targeted by two aspects, the high-end utilization and balanced utilization of RE resources. In order to add value to RE resources,

关键词：稀土元素材料科学与工程资源利用化学稀土材料有效管理平衡利用电子结构

Dopant Occupancy in MgO-Codoped Lithium Niobate Crystals

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Journal of Rare Earths 2006年第z1期24卷 276-280页

作者： He Xiangke xue dongfeng State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116023 China State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China Key Laboratory for Micro/Nano Technology and System of Liaoning Province Dalian University of Technology Dalian 116023 China

On the basis of the bond valence model, the preferential occupancy of various dopant such as Mn2+, Eu3+, Er3+, Nd3+, Lu3+, Yb3+, In3+, Cr3+, Fe3+ and Ti4+ in the ideal stoichiometric lithium niobate (SLN) crystallographic frame was investigated in a viewpoint of chemical bonds. Theoretical analysis indicates that the dopant occupancy is significantly influenced by the anti-site Nb4+Li. Our work also shows that Mg-like ions (Mg2+, Zn2+, In3+, Sc3+) have a repulsive effect on Nb4+Li ions. When removing Nb4+Li ion by codoping Mg-like ions, the dopant occupancy in the LN crystallographic frame is determined by the natural characteristics of dopant, which is consistent well with the result in the ideal SLN crystals.

关键词： lithium niobate bond valence model codoping dopant occupancy

Chemical Bond Analysis of Single Crystal Growth of Magnesium Oxide

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Journal of Rare Earths 2006年第z1期24卷 245-248页

作者： Zhang Xu xue dongfeng State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China

Starting from the crystallographic structure of magnesium oxide (MgO), both the chemical bond model of solids and Pauling's third rule (polyhedral sharing rule) were employed to quantitatively analyze the chemical bonding structure of constituent atoms and single crystal growth. Our analytical results show that MgO single crystals prefer to grow along the direction and the growth rate of the {100} plane is the slowest one. Therefore, the results show that the {100} plane of MgO crystals can be the ultimate morphology face, which is in a good agreement with our previous experimental results. The study indicate that the structure analysis is an effective tool to control the single-crystal growth.

关键词： magnesium oxide crystal structure chemical bond

Bonding Energy and Growth Habit of Lithium Niobate Single Crystals

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Journal of Rare Earths 2006年第z1期24卷 241-244页

On the basis of crystallographic structure of lithium niobate (LN), the bonding energy was quantitatively calculated by the bond valence sum model, which was employed to investigate the crystal growth. A possible relationship between the crystal growth habit and chemical bonding energy of LN crystals are found. It is found that the higher the bond energy, the slower the growth rate, and the more important the plane. The analytical results indicate that (012) plane is the most influential face for the LN crystal growth, which consists well with the standard card (JCPDS Card: 20-0631) and our previous experimental observation. The current work shows that the chemical bond analysis of LN crystals allows us to predict its growth habit and thus to obtain the expected morphology during the spontaneous growth.

关键词： lithium niobate chemical bond bonding energy growth habit

Crystallographic Analysis of Tapering of ADP Crystallites

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Journal of Rare Earths 2006年第z1期24卷 228-232页

作者： Xu Dongli xue dongfeng State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China State Key Laboratory of Fine Chemicals Department of Materials Science and Chemical Engineering School of Chemical Engineering Dalian University of Technology Dalian 116012 China

On the basis of crystallographic characteristics of ADP (ammonium dihydrogen phosphate) crystals and the selected growth conditions, the growth habit of ADP crystals was studied. In comparison with pyramidal planes, the growth rate of prismatic faces is slower and more sensitive to the additives and impurities for ADP crystals. When the supersaturation is low, the advance of growth steps on prismatic face can be blocked by ethanol or impurities, the crystal morphology is changed from the tetragonal prism to shuttle (i.e., the tapered shape). The tapering formation of ADP crystallites was structurally studied in a novel view.

关键词： crystal structure chemical bond growth habit ADP hydrogen bond tapering