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Efficient Spin-Flip between Charge-Transfer States for High-Performance Electroluminescence, without an Intermediate Locally Excited State

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Research 2024年第1期2023卷 339-349页

作者： Donghai Zhang Shanshan Jiang Xiaodong Tao Fulin lin lingyi Meng Xu-lin chen Can-Zhong Lu State key laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian 350002China Fujian Science and Technology Innovation laboratory for Optoelectronic Information of china FuzhouFujian 350108China Xiamen key laboratory of Rare Earth Photoelectric Functional materials Xiamen Institute of Rare Earth MaterialsHaixi InstitutesChinese Academy of SciencesXiamenFujian 361021China university of Chinese Academy of sciences Beijing 100049China

Thermally activated delayed fluorescence(TADF)materials with both high photoluminescence quantum yield(PLQY)and fast reverse intersystem crossing(RISC)are strongly desired to realize efficient and stable organic light-emitting diodes(OLEDs).Control of excited-state dynamics via molecular design plays a central role in optimizing the PLQY and RISC rate of TADF materials but remains ***,3 TADF emitters possessing similar molecular structures,similar high PLQYs(89.5%to 96.3%),and approximate energy levels of the lowest excited singlet states(S_(1)),but significantly different spin-flipping RISC rates(0.03×10^(6) s^(−1) vs.2.26×10^(6) s^(−1))and exciton lifetime(297.1 to 332.8μs vs.6.0μs)were systematically synthesized to deeply investigate the feasibility of spin-flip between charge-transfer excited states(^(3)CT–^(1)CT)transition.

关键词： transition lifetime desired

Core-shell fibrous vascular grafts with the nitric oxide releasing property

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Science china Chemistry 2010年第3期53卷 528-534页

作者： ZHANG Lei,WANG Kai,ZHAO Qiang,ZHENG WenTing,WANG ZhiHong,WANG ShuFang & KONG Deling key laboratory of bioactive materials,ministry of education college of life Science,nankai university,tianjin 300071,china key laboratory of bioactive materials Ministry of Education college of life Science Nankai University Tianjin China

Small-diameter vascular grafts with the nitric oxide(NO) releasing property were designed and *** N,N'-dibutyl-1,6-hexanediamine(DBHD/N2O2) was first synthesized as the NO donor and doped into the biocompatible polymer poly(ε-caprolactone)(PCL).The fibrous vascular grafts were fabricated by *** the reduced platelet adhesion observed on the NO releasing grafts,the cytotoxicity and burst release were apparent,especially at a higher loading level of the NO *** order to solve this problem,core-shell structured nanofibers,in which PCL or gelatin is the shell and PCL doped with the NO donor is the core,were fabricated via coaxial *** core-shell structure made the NO release more steady and controllable,and the cell compatibility was improved.

关键词： nitric oxide release coaxial electrospinning platelet adhesion vascular graft

Grain growth behavior and properties of high-entropy pseudobrookite(Mg,Co,Ni,Zn)Ti_(2)O_(5) ceramics

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Journal of Advanced Ceramics 2024年第6期13卷 757-768页

作者： Xiaohui Ma Jinyu Wu lingyi Meng Jinfeng Zhang Heng chen Liwen Yan Anran Guo Jiachen liu key laboratory of Advanced Ceramics and Machining Technology of ministry of education School of Materials Science and EngineeringTianjin UniversityTianjin 300072China Xiamen key laboratory of Rare Earth Photoelectric Functional materials Xiamen Institute of Rare Earth MaterialsHaixi InstitutesChinese Academy of SciencesXiamen 361021China

It is well known that the grain size of high-entropy ceramics is quite small owing to the sluggish diffusion effect. However, abnormal grain growth often occurs in high-entropy pseudobrookite ceramics, ultimately resulting in the formation of many abnormally grown grains with a grain size as large as 50 μm. To study this phenomenon, the grain growth behavior of high-entropy pseudobrookite ceramics was systematically investigated in this paper. The results demonstrate that the starting material powders first react with each other to form a high-entropy intermediate phase and calcined TiO_(2) powders (TiO_(2)-1100 ℃), and then as the sintering temperature increases, the formed high-entropy intermediate phase further reacts with TiO_(2)-1100 ℃ to form high-entropy pseudobrookite ceramics. Thus, in this system, in addition to the sluggish diffusion effect, the grain sizes of the high-entropy intermediate phase and TiO_(2)-1100 ℃ also affect the morphology of high-entropy pseudobrookite. Compared to nanosized TiO_(2), micron-sized TiO_(2) has a lower sintering activity. Therefore, the high-entropy intermediate phases (Mg,Co,Ni,Zn)TiO_(3) and TiO_(2)-1100 ℃ prepared with micron-sized starting materials exhibit lower grain sizes, finally resulting in the formation of high-entropy (Mg,Co,Ni,Zn)Ti_(2)O_(5) with small grain sizes. Moreover, nano-indentation and thermal conductivity tests were carried out on high-entropy (Mg,Co,Ni,Zn)Ti_(2)O_(5) with different morphologies. The results show that the hardness of high-entropy (Mg,Co,Ni,Zn)Ti_(2)O_(5) increases from 6.05 to 9.95 GPa as the grain size increases, whereas the thermal conductivity decreases from 2.091±0.006 to 1.583±0.006 W·m^(−1)·K^(−1). All these results indicate that high-entropy (Mg,Co,Ni,Zn)Ti_(2)O_(5) with a small grain size is a potential material for thermal protection.

关键词： grain size sluggish diffusion effect two-step solid phase process high-entropy intermediate phase high-entropy pseudobrookite ceramic

Preparation of Li_4Ti_5O_(12) submicrospheres and their application as anode materials of rechargeable lithium-ion batteries

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Science china Chemistry 2011年第6期54卷 936-940页

作者： ZHANG Ai, ZHENG ZongMin, chenG FangYi, TAO ZhanLiang & chen Jun key laboratory of Advanced Energy materials Chemistry, ministry of education college of Chemistry, nankai university, tianjin 300071, china key laboratory of Advanced Energy materials Chemistry Ministry of Education college of Chemistry Nankai University Tianjin China

We report on the preparation of spinel Li4Ti5O12 submicrospheres and their application as anode materials of rechargeable lithium-ion batteries. The spinel Li4Ti5O12 submicrospheres are synthesized with three steps of the hydrolysis of TiCl4 to form rutile TiO2, the hydrothermal treatment of rutile TiO2 with LiOH to prepare an intermediate phase of LiTi2O4+δ, and the calcinations of LiTi2O4+δ to obtain spinel Li4Ti5O12. The as-prepared products are investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The diameters of Li4Ti5O12 submicrospheres with novel hierarchical microstructures are about 200–300 nm with the assembly of 20–30 nm nanoparticles. The electrochemical properties of Li4Ti5O12 submicrospheres are measured by galvanostatical discharge/charge test and cyclic voltammetry (CV). The as-prepared Li4Ti5O12 display excellent discharge/charge rate and cycling capability. A high discharge capacity of 174.3 mAh/g is obtained in the first discharge at 1 C rate. Meanwhile, there is only tiny capacity fading with nearly 100% columbic efficiency in the sequential 5–50 cycles. Moreover, lithium-ion diffusion coefficient in Li4Ti5O12 is calculated to be 1.03 × 10-7 cm2/s. The present results indicate that the as-prepared Li4Ti5O12 submicrospheres are promising anode candidates of rechargeable Li-ion batteries for high-power applications.

关键词： Li4Ti5O12 TiO2 TiCl4 anode material lithium-ion battery

Hierarchical In_(2)S_(3)microflowers decorated with WO_(3)quantum dots:Sculpting S-scheme heterostructure for enhanced photocatalytic H_(2)evolution and nitrobenzene hydrogenation

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Journal of materials Science & Technology 2024年第7期174卷 218-225页

作者： Yuan lin Lv chen Jianhua Zhang Yunyun Gui Lijun liu Hubei key laboratory of Biomass Fibers and Eco-dyeing&Finishing College of Chemistry and Chemical EngineeringWuhan Textile UniversityWuhan 430200China

Solar energy conversion and high-value chemical production are of utmost ***,the de-velopment of efficient photocatalysts with strong redox ability remains *** we report a unique 3D/0D In_(2)S_(3)/WO_(3)S-scheme heterojunction photocatalyst obtained by depositing WO_(3)quantum dots(QDs)onto hierarchical In_(2)S_(3)*** In_(2)S_(3)/WO_(3)composite exhibits outstanding visible light absorption,with a maximum optical response of up to 600 *** electronic interaction and charge separation at interfaces are explored by in situ X-ray photoelectron spectroscopy(XPS)and density func-tional theory(DFT)*** difference in work function causes In_(2)S_(3)to donate electrons to WO_(3)upon combination,leading to the formation of an internal electric field(IEF)at the *** to the IEF and bent energy bands,the transfer and separation of photogenerated charge carriers follow an S-scheme pathway within In_(2)S_(3)/WO_(3).Owing to the strong redox ability,spatial charge separation and lower H 2-generation barrier of S active sites,the optimized In_(2)S_(3)/WO_(3)heterojunctions show enhanced photocatalytic hydrogen evolution of 0.39 mmol h^(-1)g^(-1),6.7 times that of pristine In_(2)S_(3).In addition,the In_(2)S_(3)/WO_(3)S-scheme heterojunctions afford a remarkable activity for photocatalytic nitrobenzene hydro-genation with nearly 98%conversion and 99%selectivity of aniline within 1 *** work might present new insights into developing efficient S-scheme heterojunctions for various photocatalytic applications.

关键词： S-scheme heterojunctions In_(2)S_(3)microflowers WO_(3)quantum dots H_(2)production Electron transfer

Effects of grain's shape-and size-polydispersities,orientation,and area fraction on tortuosity and permeability of 2D granular media

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Particuology 2024年第7期90卷 535-557页

作者： Ke Cao Huisu chen Mohammad Iqbal Khan Mingqi Li lin liu Jiangsu key laboratory of Construction materials School of Materials Science and EngineeringSoutheast UniversityNanjing 211189China Department of Civil Engineering College of EngineeringKing Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia School of Civil and Transportation Engineering Hebei University of TechnologyTianjin 300401China college of Civil and Transportation Engineering Hohai UniversityNanjing210098China

The microstructure of granular media, including grain's shape- and size-polydispersities, orientation, and area fraction can potentially affect its permeability. However, few studies consider the coupling effects of these features. This work employs geometrical probability and stereology to establish quantitative relationships between the above microstructural features and the geometric tortuosity of the two-dimensional granular media containing superellipse, superoval, and polygon grains. Then the lattice Boltzmann method (LBM) is used to determine the permeabilities of these granular media. By combining the tortuosity model and the LBM-derived permeabilities, modified K–C equations are formulated to predict the permeability and the shape factor, considering the grain's shape- and size-polydispersities, orientation, and area fraction. The reliability of these methods can be verified by comparing them with both our simulations and available experimental, theoretical, and numerical data reported in the literature. The findings implicate that the tortuosity and permeability of the granular media are strongly correlated with the grain's shape, orientation, and area fraction but unaffected by the size polydispersity and spatial arrangement of grains. Only circularity is not enough to derive a unified formula for considering the impact of grain shape on tortuosity and permeability, other shape parameters need to be explored in the future.

关键词： Geometric tortuosity Konzey-Carman equation Shape and size ploydispersities Grain orientation Lattice Boltzmann method Granular media

Hollow Metal-Organic Framework/MXene/Nanocellulose Composite Films for Giga/Terahertz Electromagnetic Shielding and Photothermal Conversion

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Nano-Micro Letters 2024年第9期16卷 161-179页

作者： Tian Mai Lei chen Pei‑lin Wang Qi liu Ming‑Guo Ma Research Center of Biomass Clean Utilization MOE Engineering Research Center of Forestry Biomass Materials and BioenergyBeijing Key Laboratory of Lignocellulosic ChemistryCollege of Materials Science and TechnologyBeijing Forestry UniversityBeijing 100083People’s Republic of China State Silica-Based materials laboratory of Anhui Province Bengbu 233000People’s Republic of China

With the continuous advancement of communication technology,the escalating demand for electromagnetic shielding interference(EMI)materials with multifunctional and wideband EMI performance has become *** the electrical and magnetic components and designing the EMI material structure have attracted extensive interest,but remain a huge ***,we reported the alternating electromagnetic structure composite films composed of hollow metal-organic frameworks/layered MXene/nanocellulose(HMN)by alternating vacuum-assisted filtration *** HMN composite films exhibit excellent EMI shielding effectiveness performance in the GHz frequency(66.8 dB at Kaband)and THz frequency(114.6 dB at 0.1-4.0 THz).Besides,the HMN composite films also exhibit a high reflection loss of 39.7 dB at 0.7 THz with an effective absorption bandwidth up to 2.1 ***,HMN composite films show remarkable photothermal conversion performance,which can reach 104.6℃under 2.0 Sun and 235.4℃under 0.8 W cm^(−2),*** unique micro-and macrostructural design structures will absorb more incident electromagnetic waves via interfacial polarization/multiple scattering and produce more heat energy via the local surface plasmon resonance *** features make the HMN composite film a promising candidate for advanced EMI devices for future 6G communication and the protection of electronic equipment in cold environments.

关键词： Metal-organic frameworks MXene Nanocellulose Electromagnetic shielding Photothermal conversion

Self-Driven Photo-Polarized Water Molecule-Triggered Graphene-Based Photodetector

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Research 2024年第2期2023卷 273-283页

作者： Shisheng lin Chang liu Xin chen Yi Zhang Hongtao lin Xutao Yu Yujiao Bo Yanghua Lu college of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027P.R.China Hangzhou Gelanfeng Technology Co.Ltd Hangzhou 310051P.R.China State key laboratory of Modern Optical Instrumentation Zhejang UniversityHangzhou 310027P.R.China key laboratory of Wide Bandgap Semiconductor materials and Devices HCSemitek CorporationYiwu 322009P.R.China Smart materials for Architecture Research Lab Innovation Center of Yangtze River DeltaZhejiang UniversityJiaxing 314100P.R.China

Flowing water can be used as an energy source for generators,providing a major part of the energy for daily ***,water is rarely used for information or electronic ***,we present the feasibility of a polarized liquid-triggered photodetector in which polarized water is sandwiched between graphene and a *** to the polarization and depolarization processes of water molecules driven by photogenerated carriers,a photo-sensitive current can be repeatedly produced,resulting in a high-performance *** response wavelength of the photodetector can be fine-tuned as a result of the free choice of semiconductors as there is no requirement of lattice match between graphene and the *** zero voltage bias,the responsivity and specific detectivity of Gr/NaCl(0.5 M)W/N-GaN reach values of 130.7 mA/W and 2.3×10^(9)Jones under 350 nm illumination,***,using a polar liquid photodetector can successfully read the photoplethysmography signals to produce accurate oxygen blood saturation and heart *** with the commercial pulse oximetry sensor,the average errors of oxygen saturation and heart rate in the designed photoplethysmography sensor are~1.9%and~2.1%,*** study reveals that water can be used as a high-performance photodetector in informative industries.

关键词： polarization polarized saturation

A novel long persistent luminescent material CaGeO_(3):Tb^(3+)with photo-stimulation properties

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Journal of Rare Earths 2024年第7期42卷 1233-1239,I0002页

作者： Wei Meng Xiaoyan Fu Tongyan lin Zewen liu Naihui chen Jiaxu Zhang Runyao liu Rujun Yang Long chen Hongwu Zhang School of Chemistry and Material sciences Ludong UniversityYantai264025China college of materials Science and Engineering Xiamen University of TechnologyXiamen361024China college of materials Xiamen UniversityXiamen361005China

A novel green long afterglow material CaGeO_(3):Tb^(3+)was synthesized by high temperature solid phase *** to the experimental results,CaGeO_(3):Tb^(3+)is a green long persistent luminescent(LPL)material with excellent ***_(3):Tb^(3+)shows LPL emission peak at 442,490.9,548.7,588.5 and 623.8 nm,corresponding to ^(5)D_(3) to^(7)F_(4)and^(5)D_(4)to^(7)F_(J)(J=6,5,4,3)transitions of Tb^(3+).Its CIE coordinates are(0.27,0.50),indicating that the afterglow emission is close to the light of green *** addition,after the excitation source is turned off,the afterglow time is longer than 90 *** an interval of 7 h,the photo-stimulation luminescence(PSL)can be observed by using 980 nm laser cyclic *** thermoluminescence(ThL)results show that there are three types of traps in the material and their depths are 0.666,0.774 and 0.892 eV respectively,which are caused by the doping of Tb^(3+).All the results show that CaGeO_(3):Tb^(3+)is an excellent long afterglow luminescent material.

关键词： Long persistent luminescence Photo-stimulation Trap CaGeO_(3):Tb^(3+) Rare earths