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Fluoro-substituted DPP-bisthiophene conjugated polymer with azides in the side chains as ambipolar semiconductor and photoresist

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Science China Chemistry 2022年第9期65卷 1791-1797页

作者： Wenlin Jiang Xiaobo Yu Cheng Li Xisha Zhang Guanxin Zhang Zitong Liu Deqing Zhang Beijing National Laboratory for Molecular Sciences Organic Solids LaboratoryInstitute of ChemistryChinese Academy of SciencesBeijing 100190China State Key Laboratory of Applied Organic Chemistry(SKLAOC) Key Laboratory of Special Function Materials and Structure DesignCollege of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

Photoresists are essential for the fabrication of flexible electronics through all-photolithographic processes.Single component semiconducting photoresist exhibits both semiconducting and photo-patterning properties,and as a result,the device fabrication process can be simplified.However,the design of semiconducting polymeric photoresist with ambipolar semiconducting property remains challenging.In this paper,we report a single component semiconducting photoresist(PFDPPF4T-N_(3))by incorporating azide groups and noncovalent conformation locks into the side alkyl chains and conjugated backbones of a diketopyrrolopyrrole-based conjugated polymer,respectively.The results reveal that PFDPP4FT-N_(3) exhibits ambipolar semiconducting property with hole and electron mobilities up to 1.12 and 1.17 cm^(2) V^(−1) s^(−1),respectively.Moreover,field effect transistors with the individual photo-patterned thin films of PFDPP4FT-N_(3) also show ambipolar semiconducting behavior with hole and electron mobilities up to 0.66 and 0.80 cm^(2) V^(−1) s^(−1),respectively.These results offer a simple yet effective design strategy for high-performance single component semiconducting photoresists,which hold great potential for flexible electronics processed by all-photolithography.

关键词： conjugated polymer ambipolar semiconductor photoresist noncovalent conformation lock diketopyrrolopyrrole

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Borophene-ZnO heterostructures:Preparation and application as broadband photonic nonvolatile memory

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Nano Research 2023年第4期16卷 5826-5833页

作者： Runsheng liu Chuang Hou Xinchao Liang zitong Wu Guoan Tai The State Key Laboratory of Mechanics and Control of Mechanical Structures and Laboratory of Intelligent Nano Materials and Devices of Ministry of Education College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

High-performance photonic nonvolatile memory which combines data storage and photosensing can achieve low power consumption and ensure computational energy efficiency.Heterostructure has been theoretically and experimentally proved to have synergistic effects between two materials,which can lead to promising electronic and optical properties for advanced optoelectronic devices.Herein,we report the preparation of borophene-ZnO heterostructures and their applications of broadband photonic nonvolatile memory.The memory shows a good switching ratio(5×10^(3))and long-term stability(3,600 s),which are superior to those of the pristine borophene or ZnO quantum dots(QDs).It is found that the memory shows a broad light response from ultraviolet(365 nm)to near infrared(850 nm).Besides,the SET voltage will decrease when the device is exposed to light,which can be attributed to the separation of holes and electrons in accelerating the formation of vacancy conductive filament.This work not only provides a promising material for next-generation photoelectric information,but also paves the way for borophene-based memory towards data storage devices.

关键词： borophene ZnO heterostructure photoluminescence(PL)quenching nonvolatile memory light control

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Frequency-Hopping Frequency Reconnaissance and Prediction for Non-cooperative Communication Network

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China Communications 2021年第12期18卷 51-64页

作者： Gao Li Wei Wang Guoru Ding Qihui Wu Zitong Liu Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 211106China College of Communications Engineering Army Engineering UniversityNanjing 210007China

The continuous change of communica-tion frequency brings difficulties to the reconnaissance and prediction of non-cooperative communication net-works.Since the frequency-hopping(FH)sequence is usually generated by a certain model with certain regularity,the FH frequency is thus predictable.In this paper,we investigate the FH frequency reconnais-sance and prediction of a non-cooperative communi-cation network by effective FH signal detection,time-frequency(TF)analysis,wavelet detection and fre-quency estimation.With the intercepted massive FH signal data,long short-term memory(LSTM)neural network model is constructed for FH frequency pre-diction.Simulation results show that our parameter es-timation methods could estimate frequency accurately in the presence of certain noise.Moreover,the LSTM-based scheme can effectively predict FH frequency and frequency interval.

关键词： non-cooperative communication network frequency-hopping frequency prediction LSTM

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(DarkAI)Mapping the large-scale density field of dark matter using artificial intelligence

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 143-159页

作者： zitong Wang Feng Shi Xiaohu Yang Qingyang Li Yanming liu Xiaoping Li School of Aerospace Science and Technology Xidian UniversityXi’an 710126China Department of Astronomy School of Physics and Astronomyand Shanghai Key Laboratory for Particle Physics and CosmologyShanghai Jiao Tong UniversityShanghai 200240China Tsung-Dao Lee Institute and Key Laboratory for Particle Physics Astrophysics and CosmologyMinistry of EducationShanghai Jiao Tong UniversityShanghai 200240China Institute for Astronomy University of EdinburghRoyal ObservatoryEdinburgh EH93HJUnited Kingdom

Herein,we present a deep-learning technique for reconstructing the dark-matter density field from the redshift-space distribution of dark-matter halos.We built a UNet-architecture neural network and trained it using the COmoving Lagrangian Acceleration fast simulation,which is an approximation of the N-body simulation with 5123 particles in a box size of 500 h^(-1)Mpc.Further,we tested the resulting UNet model not only with training-like test samples but also with standard N-body simulations,such as the Jiutian simulation with 61443particles in a box size of 1000 h^(-1)Mpc and the ELUCID simulation,which has a different cosmology.The real-space dark-matter density fields in the three simulations can be reconstructed reliably with only a small reduction of the cross-correlation power spectrum at 1%and 10%levels at k=0.1 and 0.3 h Mpc-1,respectively.The reconstruction clearly helps to correct for redshift-space distortions and is unaffected by the different cosmologies between the training(Planck2018)and test samples(WMAP5).Furthermore,we tested the application of the UNet-reconstructed density field to obtain the velocity&tidal field and found that this approach provides better results compared with the traditional approach based on the linear bias model,showing a 12.2%improvement in the correlation slope and a 21.1%reduction in the scatter between the predicted and true velocities.Thus,our method is highly efficient and has excellent extrapolation reliability beyond the training set.This provides an ideal solution for determining the three-dimensional underlying density field from the plentiful galaxy survey data.

关键词： dark matter large-scale structure cosmology

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Residents’ Preferences for Rural Housing Disaster Insurance Attributes in Central and Western Tibet

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International Journal of Disaster Risk Science 2023年第4期14卷 697-711页

作者： Tingting Yang zitong Li Yuan Bai Xinli liu Tao Ye Key Laboratory of Environmental Change and Natural Disasters Ministry of EducationBeijing Normal UniversityBeijing 100875China School of Economics Peking UniversityBeijing 100871China Archives Department Beijing Normal UniversityBeijing 100875China State Key Laboratory of Earth Surface Processes and Resource Ecology(ESPRE) Beijing Normal UniversityBeijing 100875China Academy of Disaster Reduction and Emergency Management Ministry of Emergency Management and Ministry of EducationBeijing 100875China Faculty of Geographical Science Beijing Normal UniversityBeijing 100875China

Understanding the heterogeneous preferences of individuals for disaster insurance attributes is critical for product improvement and policy design.In an era of global environmental change,the Qinghai-Tibet Plateau is a hotspot of natural hazards.Improving the capability of rural housing disaster insurance to foster local residents’disaster resilience is of great signifcance but remains under addressed.We used a discrete choice experiment approach to provide the frst estimates of rural residents’preferences for rural housing disaster insurance attributes in central and western Tibet.We estimated residents’preferences and willingness-to-pay for the sum insured,subsidy rate,insured object,and perils covered.The potential impacts of increasing the sum insured,expanding the insured object,and lowering subsidy rates were evaluated.Our results suggest that residents prefer products with a high sum insured,high subsidy rate,and a complete list of insured objects.Residents who have experienced specifc hazards tend to prefer the corresponding perils covered.Females and residents who have a closer social network are more likely to purchase insurance.Product improvement and policy simulation results suggest that,while lowering the subsidy rate,increasing the sum insured and expanding the insured object could promote participation and improve residents’welfare.Our results could improve the understanding of the preferences of households in remote regions and support policy implementations.

关键词： Discrete choice experiment Preference for insurance attributes Qinghai-Tibet Plateau Rural housing disaster insurance Willingness-to-pay

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Crystalline BC_(2)N quantum dots

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Nano Research 2023年第5期16卷 7837-7843页

作者： Pengyu Zhang Chuang Hou Wei Shao Runsheng liu zitong Wu Guoan Tai The State Key Laboratory of Mechanics and Control of Mechanical Structures and Laboratory of Intelligent Nano Materials and Devices of Ministry of Education College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

Ternary materials composed of boron,carbon,nitrogen have drawn tremendous attention because of their suitable band gap,high carrier mobility,high thermal conductivity.The properties can effectively compensate for the deficiencies of other typical carbon-based and boron-based materials,such as graphene,borophene,hexagonal boron nitride.Although the theoretical progress has advanced the development of ternary materials,it is still a great challenge to synthesize the new nanostructures with good crystallinity and high yield at low dimensional scales.Herein,we report that BC_(2)N quantum dots(QDs)can be successfully prepared by in-situ two-step thermal decomposition of sodium cyanoborohydride in a hydrogen-rich environment.The results show that the as-prepared BC_(2)N QDs have good crystallinity and high yield.The BC_(2)N QDs have an average lateral size of 3.7 nm and an average thickness of 2.83 nm.The experimental results show that the QDs are semiconducting with an optical band gap of 2.15 eV.Furthermore,a fabricated BC_(2)N QDs-based nonvolatile memory shows a low SET operating voltage(0.74 V)and a high ON/OFF ratio(more than 1.74×10^(3))as well as good stability.

关键词： BC_(2)N quantum dots graphene borophene non-volatile memory

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Large-scale App privacy governance

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Frontiers of Engineering Management 2022年第4期9卷 640-652页

作者： zitong LI Zhuoya FAN Junxu liu Leixia WANG Xiaofeng MENG School of Information Renmin University of ChinaBeijing 100872China

Recently,the problem of mobile applications(Apps)leaking users’private information has aroused wide concern.As the number of Apps continuously increases,effective large-scale App governance is a major challenge.Currently,the government mainly filters out Apps with potential privacy problems manually.Such approach is inefficient with limited searching scope.In this regard,we propose a quantitative method to filter out problematic Apps on a large scale.We introduce Privacy Level(P-Level)to measure an App’s probability of leaking privacy.P-Level is calculated on the basis of Permission-based Privacy Value(P-Privacy)and Usage-based Privacy Value(U-Privacy).The former considers App permission setting,whereas the latter considers App usage.We first illustrate the privacy value model and computation results of both values based on real-world dataset.Subsequently,we introduce the P-Level computing model.We also define the P-Level computed on our dataset as the PL standard.We analyze the distribution of average usage and number of Apps under the levels given in the PL standard,which may provoke insights into the large-scale App governance.Through P-Privacy,U-Privacy,and P-Level,potentially problematic Apps can be filtered out efficiently,thereby making up for the shortcoming of being manual.

关键词： privacy risk Privacy Level quantification large-scale App governance

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Selenophene-Flanked Diketopyrrolopyrrole Based Conjugated Polymers for Ambipolar Field-Effect Transistors

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Chinese Journal of Chemistry 2020年第10期38卷 1075-1080页

作者： Dandan Shi Xiaobo Yu Liangliang Chen Daoliang Chen Zitong Liu Xisha Zhang Guanxin Zhang Deqing Zhang Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsCAS Center of Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBejjing 100049China

Summary of main observation and conclusion The development of selenophene-flanked DPP(SeDPP)based copolymers,especially for the ambipolar ones,lags behind other aromatic group flanked DPP-based polymers.Herein,we report two new ambipolar SeDPP-based conjugated polymers.One is the alternating polymer PSeDPPFT with normal SeDPP and 3,4-difluorothiophene units.The other is PSeFDFT,in which the electron acceptor unit is replaced by a new SeDPP derivative,referred as to half-fused SeDPP.The more planar structure of half fused SeDPP endows the backbone of PSeFDFT with good rigidity and planarity.Both polymers exhibit ambipolar transporting properties in air.The PSeFDFT based fleld-effect transistors(FETs)display higher and more balanced ambipolar properties with μnave of 0.27 cm2·V-1·s-1,μe ave of 0.18 cm2·V-1·s-1,and μh ave/μeave of 1.5 than those of PSeDPPFT(μhave=0.11cm2·V-1·s-1,μeave=0.042cm2·V-1·s-1,and μh/μe=2.6).This is attributed to the more planar structure,lower LUMO level,higher HOMO level,and better interchain packing orientations of PSeFDFT by comparing with PSeDPPFT.Therefore,a new molecular design strategy to modulate the hole and electron transporting properties is proposed for conjugated D-A polymers.

关键词： planar conjugated fused

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N-Aryl diketopyrrolopyrrole derivatives towards organic optical and electronic materials

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Chinese Chemical Letters 2023年第6期34卷 157-163页

作者： Jinqiu Meng Nan Luo Guanxin Zhang Xiangfeng Shao Zitong Liu Deqing Zhang State Key Laboratory of Applied Organic Chemistry(SKLAOC) Key Laboratory of Special Function Materials and Structure DesignCollege of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

Diketopyrrolopyrrole(DPP)and related derivatives have drawn great attention due to their applications in organic optical/electronic materials.Progress in these materials is associated with developments in the syntheses of the DPP family.Chemical modification of DPP at nitrogen atom,including N-alkylation and N-arylation,is an effective strategy to improve its physical and chemical properties,such as solubility,optical and semiconducting properties.However,N-arylation of DPPs remains challenging compared to the easily accessible N-alkylation.Herein,the synthesis of N-aryl DPP derivatives and correlatedπ-expanded DPPs are summarized,and their optical/electronic properties are introduced.The future perspectives of N-aryl DPP derivatives are also discussed.

关键词： Diketopyrrolopyrrole N-arylation π-expanded derivatives Organic optical material Organic electronic material

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The Control of Intramolecular Through-Bond and Through-Space Coupling in Single-Molecule Junctions

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CCS Chemistry 2022年第2期4卷 713-721页

作者： Zhibing Tan Wenlin Jiang Chun Tang Li-Chuan Chen Liangliang Chen Junyang liu Zitong Liu Hao-Li Zhang Deqing Zhang Wenjing Hong State Key Laboratory of Physical Chemistry of Solid Surfaces iChEMCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005 Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic SolidsCAS Center of Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190 State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000

Electronic coupling between individual building blocks plays an essential role in charge transport through molecular materials and devices.However,the investigation of the transmission mechanism in charge transport via intramolecular coupling remains challenging.Herein,we demonstrate the transition of the intramolecular through-bond and through-space coupling in a single-molecule junction with a family of diketopyrrolopyrrole(DPP)derivative by varying intramolecular donor–acceptor(D–A)interactions.The transition is accomplished by regulating D–A interactions by inserting different aromatic rings inside,leading to two orders of magnitude difference of the single-molecule conductance.The flicker noise analysis demonstrates that the conductance difference arises from the control of the contribution between through-bond and through-space coupling.These findings are further supported by the calculation that the intramolecular coupling among molecular building blocks correlates with the D–A interaction,providing a promising way to regulate the contribution between through-bond and through-space coupling in the charge transport through molecular materials and devices.

关键词： intramolecular coupling single-molecule junctions D-A interaction through-bond throughspace

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