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Chiral thermally activated delayed fluorescence materials for circularly polarized organic light-emitting diodes

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Science China Chemistry 2024年第4期67卷 1097-1116页

作者： Li Yuan Yi-Pin Zhang You-Xuan Zheng State Key Laboratory of Coordination Chemistry Collaborative Innovation Center of Advanced MicrostructuresJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Chirality is an important natural characteristic of organic molecules,and chiral organic molecules have shown extensive application in areas such as pharmaceutical development and material science.Benefiting from the ability to achieve circularly polarized luminescence(CPL),chiral luminescent materials have shown potential applications in anti-glare display,optical communication and,3D display,etc.Due to the ability to harvest both singlet and triplet excitons by a fast reverse intersystem crossing process without involving noble metals,chiral thermally activated delayed fluorescence(TADF)materials with point chirality,axial chirality,planar chirality and helical chirality are regarded as the state-of-the-art materials for circularly polarized organic light-emitting diodes(CP-OLEDs).In recent years,the chiral TADF materials and CP-OLEDs have rapidly developed,but unfortunately,the dissymmetry factors(g)are far from the requirement of practical applications.The ideal emitters and devices should have both high efficiency and a g factor,or at least a balance between these two elements.This review gives an overview of recent progress in chiral TADF materials,with a particular focus on the chiral skeleton,CPL property and device performance.Furthermore,the molecular design concept,device structure and methods to improve the g factors of chiral materials and CP-OLEDs are also discussed.

关键词： chiral thermally activated delayed fluorescence material chiral skeleton circularly polarized luminescence circularly polarized organic light-emitting diodes dissymmetry factor

Signature of Superconductivity in Pressurized La_(4)Ni_(3)O_(10)

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Chinese Physics Letters 2024年第1期41卷 77-84页

作者：李庆张英杰项浙宁张宇航祝熙宇闻海虎 National Laboratory of Solid State Microstructures and Department of Physics Center for Superconducting Physics and MaterialsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

The discovery of high-temperature superconductivity near 80K in bilayer nickelate La_(3)Ni_(2)O_(7)under high pressures has renewed the exploration of superconducting nickelate in bulk materials.The extension of superconductivity in other nickelates in a broader family is also essential.Here,we report the experimental observation of superconducting signature in trilayer nickelate La_(4)Ni_(3)O_(10)under high pressures.By using a modified solgel method and post-annealing treatment under high oxygen pressure,we successfully obtained polycrystalline La_(4)Ni_(3)O_(10)samples with different transport behaviors at ambient pressure.Then we performed high-pressure electrical resistance measurements on these samples in a diamond-anvil-cell apparatus.Surprisingly,the signature of possible superconducting transition with a maximum transition temperature(T_(c))of about 20K under high pressures is observed,as evidenced by a clear drop of resistance and the suppression of resistance drops under magnetic fields.Although the resistance drop is sample-dependent and relatively small,it appears in all of our measured samples.We argue that the observed superconducting signal is most likely to originate from the main phase of La_(4)Ni_(3)O_(10).Our findings will motivate the exploration of superconductivity in a broader family of nickelates and shed light on the understanding of the underlying mechanisms of high-T_(c) superconductivity in nickelates.

关键词： materials superconductivity signature

Ferromagnetism and insulating behavior with a logarithmic temperature dependence of resistivity in Pb_(10-x)Cux(PO_(4))_(6)O

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 106-111页

作者： Yuhang Zhang Cong Liu Xiyu Zhu Hai-Hu Wen center for Superconducting Physics and materials National Laboratory of Solid State Microstructures and Department of PhysicsNational Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Recent claim of discovering above-room-temperature superconductivity(Tc≈400 K)at ambient pressure in copper doped apatite Pb10(PO_(4))_(6)O has stimulated world-wide enthusiasm and impulse of motion.A lot of follow-up works have been carried out with controversial conclusions.To check whether superconductivity is really present or absent in the material,we need samples which should have a rather pure phase of Pb_(10-x)Cux(PO_(4))_(6)O.Here we report the characterization results from the Pb_(10-x)Cux(PO_(4))_(6)O with a fraction of about 97 wt.%inferred from the fitting to the X-ray diffraction pattern,if assuming Cu2S as the only impurity.The resistivity measurements show that it is a semiconductor characterized roughly by a ln(1/T)temperature dependence in wide temperature region without trace of superconductivity.Magnetization measurements show that it has a general ferromagnetic signal with a weak superparamagnetic background.Many grains of the sample show clear interactions with a Nb Fe B magnet.The detected Cu concentration is much lower than the expected nominal one.Our results show the absence of metallicity and superconductivity in Pb_(10-x)Cux(PO_(4))_(6)O at ambient pressure,and suggest the presence of strong correlation effect.

关键词： superconductivity Pb10(PO4)6O ferromagnetic correlation effect

Stark splitting of intense red emission for Er^(3+)in O_(h) symmetry sites realizing optical temperature sensing in biological applications

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Rare Metals 2024年第3期43卷 1263-1274页

作者： Yue Guo Lin-Jun Qin Jing Xu Xiao-Ping Jiang Xiao-Yu Yue Yi Hou Hao Shi Li-Xi Wang Qi-Tu Zhang Collage of materials Science and Engineering Nanjing Tech UniversityNanjing211816China Jiangsu collaborative innovation center for advanced Inorganic Function Composites Nanjing211816China

Optical temperature sensing based on the fluorescence intensity ratio(FIR)of red emission for lanthanide ions holds significant relevance in non-contact temperature measurement for biological application.In this study,the perovskite-structured KZnF_(3)is utilized as a host material for Er^(3+)to achieve a high-purity upconversion(UC)red emission.The observed Stark splitting of the red emission peak provides evidence of the energy level splitting of Er^(3+).Group theory is employed to decompose the spectral branching of Er^(3+)under the point group symmetry of KZnF_(3),allowing for the derivation of Stark splitting energy levels induced by the crystal field effect.The optical temperature-sensing behavior of the red UC luminescence was investigated,specifically examining the FIR of the splitting sub-peaks,which exhibited an exponential relationship with temperature.The KZnF_(3):Yb^(3+),Er^(3+)demonstrated a relative sensitivity(S_(r))of 0.00182%·K^(-1)at 298 K,highlighting its excellent response to temperature.Ex vivo bio-thermometry experiments conducted on chicken breast validated the material's ability to penetrate biological tissues and showed its significant sensitivity of the FIR to temperature.These results establish KZnF_(3):Yb^(3+),Er^(3+)as a promising material for optical thermometry in various biological applications.

关键词： KZnF_(3) Er^(3+) Upconversion luminescence Stark splitting Temperature sensing

Constructing electron-blocking grain boundaries in garnet to suppress lithium dendrite growth

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Journal of advanced Ceramics 2024年第2期13卷 166-175页

作者： Xing Xiang Zecheng Fang Congkun Du Zhenzhen Zhao Jiajia Chen Yanhua Zhang Huihu Wang Chenhuinan Wei Fei Chen Qiang Shen hubei Provincial Key Laboratory of Green materials for Light Industry Hubei University of TechnologyWuhan 430068China hubei Longzhong Laboratory Wuhan University of Technology Xiangyang Demonstration ZoneXiangyang 441000China collaborative innovation center of Green Light-weight materials and Processing Hubei University of TechnologyWuhan 430068China New materials and Green Manufacturing Talent Introduction and innovation Demonstration Base Hubei University of TechnologyWuhan 430068China State Key Lab of advanced Technology for materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Li_(7)La_(3)Zr_(2)O_(12)(LLZO)is considered as a promising solid-state electrolyte due to its high ionic conductivity,wide electrochemical window,and excellent electrochemical stability.However,its application in solid-state lithium metal batteries(SSLMBs)is impeded by the growth of lithium dendrites in LLZO due to some reasons such as its high electronic conductivity.In this study,lithium fluoride(LiF)was introduced into Ta-doped LLZO(LLZTO)to modify its grain boundaries to enhance the performance of SSLMBs.A nanoscale LiF layer was uniformly coated on the LLZTO grains,creating a threedimensional continuous electron-blocking network at the grain boundaries.Benefiting from the electronic insulator LiF and the special structure of the modified LLZTO,the symmetric cells based on LLZO achieved a high critical current density(CCD)of 1.1 mA·cm^(-2)(in capacity-constant mode)and maintained stability over 2000 h at 0.3 mA·cm^(-2).Moreover,the full cells combined with a LiFePO_(4)(LFP)cathode,demonstrated excellent cycling performance,retaining 97.1% of capacity retention after 500 cycles at 0.5 C.Therefore,this work provides a facile and effective approach for preparing a modified electrolyte suitable for high-performance SSLMBs.

关键词： solid electrolyte garnet lithium dendrite microstructure solid-state batteries

Low-energy-consumption temperature swing system for CO_(2) capture by combining passive radiative cooling and solar heating

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Green Energy & Environment 2024年第3期9卷 507-515页

作者： Ying-Xi Dang Peng Tan Bin Hu Chen Gu Xiao-Qin Liu Lin-Bing Sun State Key Laboratory of materials-Oriented chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)College of Chemical EngineeringNanjing Tech UniversityNanjing211816China

Temperature-swing adsorption(TSA)is an effective technique for CO_(2) capture,but the temperature swing procedure is energy-intensive.Herein,we report a low-energy-consumption system by combining passive radiative cooling and solar heating for the uptake of CO_(2) on commercial activated carbons(CACs).During adsorption,the adsorbents are coated with a layer of hierarchically porous poly(vinylidene fluoride-co-hexafluoropropene)[P(VdF-HFP)HP],which cools the adsorbents to a low temperature under sunlight through radiative cooling.For desorption,CACs with broad absorption of the solar spectrum are exposed to light irradiation for heating.The heating and cooling processes are completely driven by solar energy.Adsorption tests under mimicked sunlight using the CACs show that the performance of this system is comparable to that of the traditional ones.Furthermore,under real sunlight irradiation,the adsorption capacity of the CACs can be well maintained after multiple cycles.The present work may inspire the development of new temperature swing procedures with little energy consumption.

关键词： CO_(2)capture Solar heating Passive radiative cooling Temperature swing adsorption

Achieving a superior Na storage performance of Fe-based Prussian blue cathode by coating perylene tetracarboxylic dianhydride amine

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Carbon Energy 2024年第5期6卷 53-64页

作者： Xin-Yuan Fu Lu-Lu Zhang Zhao-Yao Chen Yunkai Xu Junxiu Wu Cheng-Cheng Wang Xiao-Kai Ding Xue-Lin Yang Jun Lu hubei Provincial collaborative innovation center for New Energy Microgrid College of Electrical Engineering&New EnergyChina Three Gorges UniversityYichangHubeiChina College of materials and chemical Engineering China Three Gorges UniversityYichangHubeiChina College of chemical and Biological Engineering Zhejiang UniversityHangzhouChina

Fe-based Prussian blue(Fe-PB)cathode material shows great application potential in sodium(Na)-ion batteries due to its high theoretical capacity,long cycle life,low cost,and simple preparation process.However,the crystalline water and vacancies of Fe-PB lattice,the low electrical conductivity,and the dissolution of metal ions lead to limited capacity and poor cycling stability.In this work,a perylene tetracarboxylic dianhydride amine(PTCDA)coating layer is successfully fabricated on the surface of Fe-PB by a liquid-phase method.The aminated PTCDA(PTCA)coating not only increases the specific surface area and electronic conductivity but also effectively reduces the crystalline water and vacancies,which avoids the erosion of Fe-PB by electrolyte.Consequently,the PTCA layer reduces the charge transfer resistance,enhances the Na-ion diffusion coefficient,and improves the structure stability.The PTCA-coated Fe-PB exhibits superior Na storage performance with a first discharge capacity of 145.2 mAh g^(−1) at 100 mA g^(−1).Long cycling tests exhibit minimal capacity decay of 0.027%per cycle over 1000 cycles at 1 A g^(−1).Therefore,this PTCA coating strategy has shown promising competence in enhancing the electrochemical performance of Fe-PB,which can potentially serve as a universal electrode coating strategy for Na-ion batteries.

关键词： cathode material coating Fe-based Prussian blue Na-ion batteries perylene tetracarboxylic dianhydride amine

Graphene from microwave-initiated upcycling of waste polyethylene for electrocatalytic reduction of chloramphenicol

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Chinese chemical Letters 2024年第4期35卷 187-192页

作者： Qiang Cao Xue-Feng Cheng Jia Wang Chang Zhou Liu-Jun Yang Guan Wang Dong-Yun Chen Jing-Hui He Jian-Mei Lu College of Chemistry Chemical Engineering and Materials ScienceCollaborative Innovation Center of Suzhou Nano Science and TechnologySoochow UniversitySuzhou 215123China

Waste polyolefin plastics, accounting for 50% of all plastic waste, represent a tremendously unexploited carbon source. Efficiently upcycling polyolefin waste into value-added carbon materials for waste water treatment avoiding using noble metals is challenging but economically and environmentally sustainable. In this work, MAX-Ti_(3)AlC_(2) supported Fe selectively catalyzes polyolefin into few-layered graphene in 5 min under microwave treatment. Graphene and MAX supported Fe(Fe@MLC) can completely(99.9%)degrade chloramphenicol(CAP) within 60 min, retain robust after 10 cycles and work efficiently at a wide p H range(3.87–13.03), avoiding the usage of noble metal. Moreover, the electrochemical active surface area(ECSA) of Fe@MLC is 2.7 times higher than that of commercial Pt/C. This work provides a cheap and efficient catalyst that promotes deconstruction of plastic wastes and indirectly degrades antibiotics thereby realizes the treatment of waste water with waste plastic.

关键词： Microwave Ti_(3)AlC_(2) Electrochemistry Dechlorination Chloramphenicol

In-situ SEM characterization of fracture mechanism of TiB/Ti-2Al-6Sn titanium matrix composites after electroshocking treatment

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Rare Metals 2024年第6期43卷 2805-2818页

作者： Ya-Ya Wu Jian Zhou Guo-Lei Han Yan Wen Zhou Wang Li-Qiang Wang Wei-Jie Lv Le-Chun Xie Lin Hua hubei Key Laboratory of advanced Technology for Automotive Components Wuhan University of Technology hubei collaborative innovation center for Automotive Components Technology Faculty of materials and Manufacturing Beijing University of Technology State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong University

In this article,in-situ scanning electron microscope characterization of the tensile properties of TiB/Ti-2Al-6Sn titanium matrix composite(TMC) was conducted before and after electroshocking treatment(EST).After EST,the tensile strength increased by 113.2 MPa.The effect of EST on the tensile strength and fracture behavior of TiB was investigated using in-situ characterization of the fracture morphology and crack propagation path of the matrix and TiB.Before EST,TiB fracture introduced cracks that extended into the matrix,resulting in material failure.After EST,the refined TiB improved the bearing capacity of the matrix,thereby improving TMC strength.Moreover,after EST,the cracks were introduced into the matrix,and resulting the fracture of matrix first.With an increase in the external load,cracks in the matrix were observed to propagate to TiB,and the refined TiB was fractured,detached,and pulled out,resulting in the formation of pores.Analyzing the propagation path of the main crack after EST showed that the deflection angle of the main crack increased.The micro structure of the fracture surface indicated that the fracture of the matrix was plastic,whereas that of TiB was brittle.After EST,the size and area of the dimples increased,confirming the increase in plasticity.The results revealed that the comprehensive mechanical properties of TiB/Ti-2Al-6Sn improved after EST.Hence,EST is an efficient method for tailoring the micro structures and mechanical properties of TMCs.

关键词： TiB/Ti-2Al-6Sn In-situ microstructure characterization Tensile properties Reinforcement Electroshocking treatment (EST)