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Enhanced piezo-response in copper halide perovskites based PVDF composite films

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Science Bulletin 2018年第19期63卷 1254-1259页

作者： Sheng Huang Gang Tang Hailong Huang Xian-gang Wu Puming Zhou Lin Zou Lei Xie Jianming Deng Xueyun Wang Haizheng Zhong Jiawang Hong Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems School of Materials Science & Engineering Beijing Institute of Technology Beijing 100081. China School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 China The 48th Research Institute China Electronics Technology Group Corporation Changsha 410111 China Key Laboratory of Neutron Physics and Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621999 China

ln-situ fabricated perovskite nanocrystals in polymeric matrix provide new generation composite mate- rials for plenty of cutting edge technology. In this work, we report the in-situ fabrication of copper halide perovskite （MA_2CuCI_4, MA：CH_3NH＋3） embedded poly（vinylidene fluoride）（PVDF） composite films. The optimized MA_2CuCI_4/PVDF composite films exhibit greatly enhanced piezo-response in comparasion with pure PVDF films. The enhancements were invesitgated and explained by applying piezo-response force microscopy （PFM） measurements and density functional theory （DFT） caculations. We proposed that the high piezoelectric properties of MA_2CuCI_4/PVDF composite films could be related to the large Cu off-centering displacement, the strong interactions between MA_2CuCI_4 and PVDF as well as large stress concentration around the MA_2CuCI_4 particles in the films. These piezoelectric composite films are expected to be suitable functional materials for flexible and/or wearable niezoelectrics.

关键词： Perovskite Piezoelectric composite films MA_2CuCI_4

High photocatalytic activity of Cu2O/TiO2/Pt composite films prepared by magnetron sputtering

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Rare Metals 2017年第10期36卷 821-827页

作者： Guang-Xiao Ren Bin Yu Yi-Ming Liu Hong-Xia Wang Wang-Gang Zhang Wei Liang College of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 China Key Laboratory of Interface Science and Engineering in Advanced Materials Taiyuan University of Technology Ministry of Education Taiyuan 030024 China

Cu2O/TiOa/Pt three-layer films were deposited on glass substrates using magnetron sputtering method. The surface morphology and the optical properties of the composite film were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, ultraviolet- visible spectroscopy （UV-Vis） and photoluminescence spectroscopy （PL）. The photocatalytic activity of the samples was evaluated by the photocatalytic degradation of methyl orange （MO） aqueous solution under visible light irradiation. The results indicate that the Cu2O/TiO2/Pt composite films are made up of three layers which are Pt layer, anatase-TiO2 layer and Cu2O layer from bottom to top. The surface of the films is even and composed of regular-shaped spherical particles. The photocatalytic activity of the Cu2O/TiO2/Pt three-layer film is much higher than that of the Cu2O/TiO2 double-layer film. Such enhancement is ascribed to the presence of Pt layer, which further inhibits the photogenerated electron-hole recombination, prolongs the lifetime of the photogenerated carriers, increases the quantum efficiency and hence improves the photocatalytic activity of the film effectively.

关键词： Cu2O/TiO2/Pt composite films Visible light Photocatalytic activity

Force-sensitive properties of FeCuNbSiB powder/silicone rubber composite films

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Rare Metals 2016年第10期35卷 784-789页

作者： Jia Zhou Zheng-Hou Zhu Xiao-Min Li Kang Du Bao-Ying Qiao Yuan Fu School of Materials and Engineering Nanchang University

composite films of different contents were prepared by Fe73.5Cu1Nb3Si13.5B9 powder as compound phase and silicone rubber as matrix phase. The thickness of film is 200 μm. Values of impedance, Z, under pressure stress were measured by TH2816LCR digital bridge. LYYL-500N high-grade-type microcomputer control pressure testing machine was used to conduct program control loading with a speed of 0.1 mm·min^-1. The results show that composite films of different contents （25 vol%, 30 vol%, and 35 vol%） have excellent force-sensitive properties in both loading process and unloading process, especially when the stress is below 0.2 MPa, the stress- impedance （SI） and ＋｜k｜ values of composite films are much higher than that in the range of 0.2-1.0 MPa. The force- sensitive properties of loading process are superior to unloading process. While the frequency is 1 kHz, the force-sensitive properties of composite films are better than 50 kHz. The optimal temperature of powder heat treatment is 500 ℃. composite film which was prepared by this kind of powder has a good force-sensitive property.

关键词： composite films Stress-impedance effect Force-sensitive properties

Versatile sensing devices for self-driven designated therapy based on robust breathable composite films

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Nano Research 2022年第2期15卷 1027-1038页

作者： Zhaofeng Ouyang Songbo Cui Houyong Yu Dewen Xu Chuang Wang Dongping Tang Kam Chiu Tam Key Laboratory of Advanced Textile Materials and Manufacturing Technology Ministry of EducationSchool of Materials Science and EngineeringZhejiang Sci-Tech UniversityHangzhou 310018China Department of Chemical Engineering Waterloo Institute for NanotechnologyUniversity of WaterlooWaterlooON N2L 3G1Canada

Flexible wearable electronics were developed for applications such as electronic skins,human-machine interactions,healthcare monitoring,and anti-infection *** conventional materials showed impermeability,single sensing ability,and no designated therapy,which hindered their *** it was still a great challenge to develop electronic devices with multifunctional sensing properties and self-driven anti-infection ***,flexible and breathable on-skin electronic devices for multifunctional fabric based sensing and self-driven designated anti-infection therapy were prepared successfully with cellulose nanocrystals/iron(Ⅲ)ion/polyvinyl alcohol(CNC/Fe^(3+)/PVA)*** resultant composite films possessed robust mechanical performances,outstanding conductivity,and distinguished breathability(3.03 kg/(m^(2)·d)),which benefited from the multiple interactions of weak hydrogen bonds and Fe^(3+) chelation and synergistic effects among CNC,polyaniline(PANI),and ***,the film could be assembled as a multifunctional sensor to actively monitor real-time physical and infection related signals such as temperature,moisture,pH,NH3,and human movements even at sweat *** importantly,this multifunctional device could act as a self-driven therapist to eliminate bacterial by the release of Fe^(3+),which was driven by the damage of metal coordination Fe-O bonds due to the high temperature caused by infection at wound ***,the composite films had potential versatile applications in electronic skins,smart wound dressings,human-machine interactions,and self-driven anti-infection therapy.

关键词： cellulose nanocrystals polyvinyl alcohol composite films mechanical performances

Preparation of narrow band gap V_2O_5/TiO_2 composite films by micro-arc oxidation

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International Journal of Minerals,Metallurgy and Materials 2012年第11期19卷 1045-1051页

作者： Qiang Luo Xin-wei Li Qi-zhou Cai Qing-song Yan Zhen-hua Pan State Key Lab of Material Processing and Dies & Mould Technology Huazhong University of Science and Technology Wuhan 430074 China National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology Nanchang Hangkong University Nanchang 330063 China

V2Os/TiO2 composite films were prepared on pure titanium substmtes via micro-arc oxidation （MAO） in electrolytes consisting of NaVO3. Their morphology and dements were characterized by scanning electron microscopy （SEM） and energy-dispersive X-ray （EDX） analysis. Phase composition and valence states of species in the films were characterized by X-ray diffraction （XRD） and X-ray photoelec- tron spectroscopy （XPS）. Ultraviolet-visible diffuse reflectance spectra （UV-Vis DRS） were also employed to evaluate the photophysical property of the films. The VEOs/TiO2 composite films show a sheet-like morphology. Not only V205 phase appears in the films when the NaVO3 concentration of the electrolyte is higher than 6,10 g/L and is loaded at the surface of anatase, but also V4＋ is incorporated into the crystal lattice of anatase. In comparison with pure TiO2 films the V2Os/TiO2 composite films exhibit significantly narrow band gap energy. The film prepared in an electrolyte consisting of NaVO3 with a concentration of 8.54 g/L exhibits the narrowest band gap energy, which is approximately 1.89 eV. The V2Os/TiO2 composite films also have the significantly enhanced visible light photocatalytic activity. The film prepared in an electrolyte consisting of NaVO3 with a concentration of 8.54 g/L exhibits the best photocatalytic activity and about 93% of rhodamine is degraded after 14 h visible light radiation.

关键词： composite films titanium dioxide vanadium pentoxide micro-arc oxidation sodium metavanadate rhodamine photocatalysis

Polypyrrole random-coil induced permittivity from negative to positive in all-organic composite films

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Journal of Materiomics 2020年第2期6卷 348-354页

作者： Peng Wang Zhongbin Pan Mingkun Wang Shuangwu Huang Jinjun Liu Jiwei Zhai School of Materials Science and Chemical Engineering Ningbo UniversityNingboZhejiang315211China School of Materials Science&Engineering Tongji University4800 Caoan RoadShanghai201804China

Percolating composites with negative permittivity can be promising candidates for ***,novel all-organic composite films containing of random coil polypyrrole(PPy)and poly(-vinylidene fluoride)(PVDF)are fabricated via a solution casting *** random coil PPy is prepared by oxidative template assembly approach for the first *** experimental result indicates that the negative permittivity is easily adjusted through controlling the random coil PPy ***,the random coil PPy contents exceeded 7 wt% the negative permittivity appear attributed to the formation of 3D interconnected PPy *** facile approach not only opens a new way to preparing negative permittivity of all-organic composite films,but also points out a route to facilitate the practical applications of metamaterials.

关键词： Polypyrrole composite films Random coil Negative permittivity

Preparation and Properties of Vegetable-Oil-Based Thioether Polyol and Ethyl Cellulose Supramolecular composite films

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Journal of Renewable Materials 2023年第4期11卷 1937-1950页

作者： Ruyu Yan Jian Fang Xiaohua Yang Na Yao Mei Li Yuan Nie Tianxiang Deng Haiyang Ding Lina Xu Shouhai Li College of Materials Science and Technology Beijing Forestry UniversityBeijing100083China Institute of Chemical Industry of Forestry Products CFANanjing210042China National Engineering Lab.for Biomass Chemical Utilization Nanjing210042China Key Lab.of Chemical Engineering of Forest Products National Forestry and Grassland AdministrationNanjing210042China Key Lab.of Biomass Energy and Material Nanjing210042China Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources Nanjing210042China

Ethyl cellulose(EC),an important biomass-based material,has excellent film-forming ***,the high interchain hydrogen bond interaction leads to a high glass transition temperature of EC,which makes it too brittle to be used *** hydroxyl group on EC can form a supramolecular system in the form of a non-covalent bond with an effective *** this study,an important vegetable-oil-based derivative named dimer fatty acid was used to prepare a novel special plasticizer for ***-fatty-acid-based thioether polyol(DATP)was synthesized and used to modify ethyl cellulose *** supramolecular composite films of DATP and ethyl cellulose were designed using the newly-formed van der Waals *** thermal stability,morphology,hydrophilicity,and mechanical properties of the composite films were all *** EC is fragile,and the addition of DATP makes the ethyl cellulose films more *** elongation at the break of EC supramolecular films increased and the tensile strength decreased with the increasing DATP *** elongation at the break of EC/DATP(60/40)and EC/DATP(50/50)was up to 40.3%and 43.4%,***,the thermal initial degradation temperature of the film with 10%DATP is higher than that of pure EC,which may be attributed to the formation of a better supramolecular system in this composite *** application of bio-based material(EC)is environmentally friendly,and the novel DATP can be used as a special and effective plasticizer to prepare flexible EC films,making it more widely used in energy,chemical industry,materials,agriculture,medicine,and other fields.

关键词： Ethyl cellulose dimeric fatty acid based thioether polyol supramolecular system composite films

Nonlinear Optical Properties of Al-Doped nc-Si-SiO_2 composite films

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Journal of Semiconductors 2007年第5期28卷 640-644页

作者：郭亨群杨琳琳王启明华侨大学信息科学与工程学院泉州362011 中国科学院半导体研究所北京100083

The nonlinear optical properties of Al-doped nc-Si-SiO2 composite films have been investigated using the time-resolved four-wave mixing technique with a femtosecond laser. The off-resonant third-order nonlinear susceptibility is observed to be 1.0 × 10-10 esu at 800nm. The relaxation time of the optical nonlinearity in the films is as short as 60fs. The optical nonlinearity is enhanced due to the quantum confinement of electrons in Si nanocrystals embedded in the SiO2 films. The enhanced optical nonlinearity does not originate from Al dopant because there are no Al clusters in the films.

关键词： Si nanocrystals composite films third-order nonlinearity time-resolved four-wave mixing

Preparation and Photoconductivity of Fe-Phthalocyanine Derivation and C_(60) composite films

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Journal of Shanghai University(English Edition) 2001年第2期5卷 156-159页

作者： CHEN Jian ming, ZHANG Jian cheng, SHEN Yue, LIU Xiu hong, YANG Lin hong School of Material Science and Engineering, Shanghai University, Shanghai, 200072, China ost.tau.ac.il

Fe (III) 2,9,16,23 tertracarboxy phthalocyanine (Fe (III) taPc) was synthesized, and bonded to polystyrene (PS) with covalence by Friedel Crafts reaction to form a new polymer (Fe (III) taPc PS) (polymer (II)). UV VIS and Infrared spectra indicated that Fe (III) taPc was successfully bonded to PS. A photoreceptor device of sandwich structure consisting of alternate layers of polymer (II) and fullerene (C 60 ) was prepared. The experiment results show that the photoconductivity of the photoreceptor is higher than that of the single layer film of polymer (II) or C 60 , because of the charge transfer effect between the layers.

关键词： phthalocyanine polystyrene C 60 photoconductivity composite films