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Highly responsive broadband Si-based MoS2 phototransistor on high-k dielectric

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Science China(Information Sciences) 2024年第6期67卷 180-189页

作者： Ali IMRAN Xin HE Jiwei LIU Qinghai ZHU Muhammad SULAMAN Fei XUE Mingsheng XU Deren YANG College of Integrated Circuits State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University ZJU-Hangzhou Global Scientific and tech.ological Innovation Centre School of Materials Science and Engineering State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University Beijing key lab.of Nanophotonics and Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of Technology

The demand for photodetectors and image sensors has grown exponentially in the past decade in biomedical, security surveillance, robotics, automotive, quality control, image recognition, and military applications, due to their superior quality, broadband detection, lower noise, and economic viability. Here,we report a MoS2channel-based phototransistor over an HfO2/n-Si substrate isolated by an h BN layer. The high photoresponse is achieved through the integration of the photoconduction, photogating, and mobility enhancement process by utilizing excellent features of MoS2, HfO2/Si, and h BN. The capacitive coupling of the photogenerated carriers by high-k dielectric HfO2leads to modulation of MoS2Fermi level due to electrostatic doping. Furthermore, the MoS2also contributes to the photogeneration of carriers due to its semiconducting nature, leading to additional photocurrent. Ultimately, the combination of photogating,photoconduction, and swift carrier extraction with remarkable mobility of 11.65 cm2· V-1· s-1results in high responsivity, external quantum efficiency, and detectivity of 4.5 × 10～8A · W-1, 0.72 × 10～6, and 6.20× 1016Jones at 266 nm illumination, respectively. The device also demonstrates broadband photoresponse from 266–1000 nm wavelengths. The high responsivity distinguishes the potential of our device for the future of optoelectronics and broadband image sensing applications.

关键词： photogating photoconduction two-dimensional materials high $~k$ dielectric carrier scattering phototransistor

Achieving highly efficient long-wavelength phosphorescence emission of large singlet-triplet energy gap materials by host-guest doping

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Science China Chemistry 2024年第6期67卷 1922-1928页

作者： Shasha Zhang Wei Yao Anqi Lv Kun Liu Yusheng Zhang Chifeng Zhou Huili Ma Huifang Shi Zhongfu An key lab.ratory of Flexible Electronics(KLOFE)&Institute of advanced Materials(IAM) Nanjing Tech UniversityNanjing211816China

High-efficiency long-wavelength phosphorescence emissions of large singlet-triplet energy gap(ΔE_(ST))materials are essential for applications in biology and ***,few long-wavelength phosphorescence emissions of largeΔE_(ST)materials have been reported due to the weak spin-orbit coupling(SOC)and strong non-radiative ***,we develop a strategy to achieve highly efficient long-wavelength room temperature phosphorescence(RTP)emission of largeΔE_(ST)materials,which display bright red RTP emission with above 400μs lifetime and 6.5%phosphorescent quantum *** experiments and theoretical calculations reveal that the fishbone-like packing and the zig-zag interactions provide favorable conditions for suppressing the non-radiative transitions of triplet state excitons,and heavy atoms effectively promote the intersystem crossing(ISC)process for highly efficient long-wavelength phosphorescence *** universality of the method for highly efficient long-wavelength RTP emission of largeΔE_(ST)materials was further investigated in various ***,these materials with largeΔE_(ST)manifest the advantages of large color contrast on the display and utilization potentiality in information *** strategy paves the way for the high contrast display and development of information encryption with RTP emission.

关键词： room temperature phosphorescence singlet-triplet energy gap host-guest doping heavy atom effect red phosphorescence

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Enhancing photoresponsiveness of metal-organic polyhedra by modifying microenvironment

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Nano Research 2024年第6期17卷 5712-5717页

作者： Long Zheng Peng Tan Qian Song Sheng-Tao Wang Min Li Xiao-Qin Liu Lin-Bing Sun state key lab.ratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China

Photoresponsiveness of materials is critical to their tunability and efficiency in terminal *** metal-organic polyhedra(PMOPs)feature intrinsic pores and remote controllab.lity,but aggregation of PMOPs in solid state hampers their photoresponsiveness ***,we report the construction of a new PMOP(Cu_(24)(C_(16)H_(12)N_(2)O_(4))_(12)(C_(18)H_(22)O_(5))12,denoted as MOP-PR-LA),where long alkyl(LA)chains act as the intermolecular poles,propping against adjacent PMOP molecules to create individual microenvironment benefiting the isomerization of photoresponsive(PR)*** ultraviolet(UV)-and visible-light irradiation,MOP-PR-LA is much easier to isomerize than the counterpart MOP-PR without *** propylene adsorption,MOP-PR has a low change of adsorption capacity(9.9%),while that of MOP-PR-LA reaches 58.6%.Density functional theory calculations revealed that PR in the cis state has a negative effect on adsorption,while the trans state of PR favors *** work might open an avenue for the construction of photoresponsive materials with high responsiveness and controllab.lity.

关键词： photoresponsive adsorption metal-organic polyhedra azobenzene long alkyl chains propylene capture

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 lab.ratory 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 tech.ique for CO_(2) capture,but the temperature swing procedure is ***,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 *** desorption,CACs with broad absorption of the solar spectrum are exposed to light irradiation for *** heating and cooling processes are completely driven by solar *** tests under mimicked sunlight using the CACs show that the performance of this system is comparable to that of the traditional ***,under real sunlight irradiation,the adsorption capacity of the CACs can be well maintained after multiple *** 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

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Atomically dispersed calcium as solid strong base catalyst with high activity and stability

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Green Energy & Environment 2024年第10期9卷 1619-1626页

作者： Xiang-Bin Shao Zhi-Wei Xing Si-Yu Liu Ke-Xin Miao Shi-Chao Qi Song-Song Peng Xiao-Qin Liu Lin-Bing Sun state key lab.ratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM)College of Chemical EngineeringNanjing Tech University30 South Puzhu Road

Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion,facile separation,and environmental ***,their widespread applications are impeded by basic components aggregation and low *** this work,we fabricate single calcium atoms on graphene （denoted as Ca1/G） by use of a redox strategy for the first time,producing solid strong base catalyst with high activity and *** precursor Ca（NO3）2is first reduced to CaO at 400℃ by the support graphene,forming CaO/G with conventional basic sites,and the subsequent reduction at 850℃ results in the generation of Ca1/G with atomically dispersed *** characterizations reveal that Ca single atoms are anchored on graphene in tetra-coordination （Ca–C2–N2） where N is in situ doped from Ca（NO3）*** atomically dispersed Ca,along with their anchoring on the support,endow Ca1/G with high activity and stability toward the transesterification reaction of ethylene carbonate with *** turnover frequency value reaches 128.0 h-1on Ca1/G,which is much higher than the traditional counterpart CaO/G and various reported solid strong bases (2.9–46.2 h-1).Moreover,the activity of Ca1/G is well maintained during 5 cycles,while 60% of activity is lost for the conventional analogue CaO/G due to the leaching of Ca.

关键词： Solid strong base Single Ca atoms Heterogeneous catalysts Transesterification Reaction

Photo-Responsive Carbon Capture over Metalloporphyrin-C_(60) Metal-Organic Frameworks via Charge-Transfer

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Research 2024年第3期2023卷 233-241页

作者： Shi-Chao Qi Zhen Sun Zhi-Hui Yang Yun-Jie Zhao Jia-Xin Li Xiao-Qin Liu Lin-Bing Sun state key lab.ratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China.

Great efforts have been devoted to the study of photo-responsive adsorption,but its current methodology largely depends on the well-defined photochromic units and their photo-driven molecular ***,a methodology to fabricate nondeforming photo-responsive sorbents is successfully *** C_(60)-fullerene doping in metalloporphyrin metal-organic frameworks(PCN-M,M=Fe,Co,or Ni)and intensively interacting with the metalloporphyrin sites,effective charge-transfer can be achieved over the metalloporphyrin-C_(60) architectures once excited by the light at 350 to 780 *** electron density distribution and the resultant adsorption activity are thus changed by excited states,which are also stable enough to meet the timescale of microscopic adsorption *** charge-transfer over Co(II)-porphyrin-C_(60) is proved to be more efficient than the Fe(II)-and Ni(II)-porphyrin-C_(60) sites,as well as than all the metalloporphyrin sites,so the CO_(2) adsorption capacity(CAC;at 0°C and 1 bar)over the C_(60)-doped PCN-Co can be largely improved from 2.05 mmol g^(−1) in the darkness to 2.69 mmol g−1 with light,increased by 31%,in contrast to photo-irresponsive CAC over all C_(60)-undoped PCN-M sorbents and only the photo-loss CAC over C_(60).

关键词： porphyrin adsorption excited

SeeMore: a spatiotemporal predictive model with bidirectional distillation and level-specific meta-adaptation

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Science China(Information Sciences) 2024年第8期67卷 147-171页

作者： Yuqing MA Wei LIU Yajun GAO Yang YUAN Shihao BAI Haotong QIN Xianglong LIU state key lab.of Software Development Environment Beihang University

Predicting future frames using historical spatiotemporal data sequences is challenging and critical, and it is receiving a lot of attention these days from academic and industrial scholars. Most spatiotemporal predictive algorithms ignore the valuable backward reasoning ability and the disparate learning complexities among different layers and hence, cannot build good long-term dependencies and spatial correlations,resulting in suboptimal solutions. To address the aforementioned issues, we propose a two-stage coarse-to-fine spatiotemporal predictive model with bidirectional distillation and level-specific meta-adaptation(See More)in this paper, which includes a bidirectional distillation network(BDN) and a level-specific meta-adapter(LMA), to gain bidirectional multilevel reasoning. In the first stage, BDN concentrates on bidirectional dynamics modeling and coarsely constructs spatial correlations of different layers, while LMA is introduced in the second fine-tuning stage to refine the multilevel spatial correlations from a meta-learning *** particular, BDN mimics the forward and backward reasoning abilities of humans in a distillation manner,which aids in the development of long-term dependencies. The LMA views learning of different layers as disparate but related tasks and guides the transfer of learning experiences among these tasks through learning complexities. Thus, each layer could be closer to its solutions and could extract more informative spatial correlations. By capturing the enhanced short-term spatial correlations and long-term temporal dependencies,the proposed model could extract adequate knowledge from sequential historical observations and accurately predict future frames whose backtracking preconditions are consistent with the historical sequence. Our work is general and robust enough to be integrated into most spatiotemporal predictive models without requiring additional computation or memory cost during inference. Extensive experimen

关键词： spatiotemporal predictive learning knowledge transfer bidirectional distillation network level-specific meta-adapter coarse-to-fine training

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Corrosion behavior of Gd_(2)Zr_(2)O_(7)thermal barrier coatings under Fe-containing environmental sediment attack

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Journal of advanced Ceramics 2024年第4期13卷 447-462页

作者： Lei Guo Yanyan Li Kai Yan School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin key lab.ratory of advanced Joining tech.ology Key Lab of Advanced Ceramics and Machining Technology of Ministry of EducationTianjin 300072China key lab.ratory of Special Equipment Safety and Energy-saving for state Market Regulation China Special Equipment Inspection&Research InstituteBeijing 100029China

Environmental sediments mainly consisting of CaO–MgO–Al_(2)O_(3)–SiO_(2)(CMAS)corrosion are a serious threat to thermal barrier coatings(TBCs),in which Fe element is usually ***_(2)Zr_(2)O_(7)TBCs are famous for their excellent CMAS *** this study,the characteristics of Fe-containing environmental sediments(CMAS-Fe)and their corrosiveness to Gd_(2)Zr_(2)O_(7)coatings were *** types of CMAS-Fe glass with different Fe contents were *** melting points were measured to be 1322–1344℃,and the high-temperature viscosity showed a decreasing trend with increasing Fe *** corrosion behavior of four types of CMAS-Fe to Gd_(2)Zr_(2)O_(7)coatings at 1350℃was *** the initial corrosion stage(0.1 h),anorthite was precipitated in CMAS-Fe with a high Ca:Si ratio,while Fe-garnet was formed in the melt with the highest Fe *** the corrosion time resulted in the formation of a reaction layer,which exhibited an interpenetrating network composed of Gd-oxyapatite,ZrO_(2),and residual *** spinel was precipitated within the reaction *** 1 h or even longer time,the reaction layers tended to be stable and compact,which had comparable hardness and fracture toughness to those of Gd_(2)Zr_(2)O_(7)*** the cyclic CMAS-Fe attack,the residual CMAS-Fe in the interpenetrating network provided a pathway for the redeposited CMAS-Fe infiltration,resulting in the continuous growth of the reaction *** a result,the Gd_(2)Zr_(2)O_(7)coatings had a large consumption in the thickness,degrading the coating ***,the Gd_(2)Zr_(2)O_(7)coatings exhibit unsatisfactory corrosion resistance to CMAS-Fe attack.

关键词： thermal barrier coatings(TBCs) Gd_(2)Zr_(2)O_(7) Fe-containing CaO-MgO-Al2O3-SiO_(2)(CMAS) corrosion resistance reaction layer

The dynamic surface evolution of halide perovskites induced by external energy stimulation

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National Science Review 2024年第4期11卷 185-194页

作者： Feiyu Cheng Pengdong Wang Chenzhe Xu Qingliang Liao Suicai Zhang Haochun Sun Wenqiang Fan Guodong Liu Zhiyun Li Yaping Kong Li Wang Fangsen Li Zhuo Kang Yue Zhang Academy for advanced Interdisciplinary Science and tech.ology State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing key lab.ratory for advanced Energy Materials and tech.ologies Key Laboratory of Advanced Materials and Devices for Post-Moore ChipsMinistry of EducationBeijing Advanced Innovation Center for Materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology Beijing Vacuum Interconnected Nanotech.Workstation(Nano-X) Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of Sciences Beijing National lab.ratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences

Tracking the dynamic surface evolution of metal halide perovskite is crucial for understanding the corresponding fundamental principles of photoelectric properties and intrinsic instability. However, due to the volatility elements and soft lattice nature of perovskites, several important dynamic behaviors remain unclear. Here, an ultra-high vacuum（UHV） interconnection system integrated by surface-sensitive probing tech.iques has been developed to investigate the freshly cleaved surface of CH3NH3PbBr3in situ under given energy stimulation. On this basis, the detailed three-step chemical decomposition pathway of perovskites has been clarified. Meanwhile, the evolution of crystal structure from cubic phase to tetragonal phase on the perovskite surface has been revealed under energy stimulation. Accompanied by chemical composition and crystal structure evolution, electronic structure changes including energy level position,hole effective mass, and Rashba splitting have also been accurately determined. These findings provide a clear perspective on the physical origin of optoelectronic properties and the decomposition mechanism of perovskites.

关键词： metal halide perovskite external energy stimulation surface dynamic evolution surface electronic structure ultra-high vacuum interconnection system