To mitigate secondary electromagnetic pollution,there is an urgent need to develop absorption-dominant electromagnetic interference(EMI)shielding materials with low density,reduced thickness,lightweight construction,f...To mitigate secondary electromagnetic pollution,there is an urgent need to develop absorption-dominant electromagnetic interference(EMI)shielding materials with low density,reduced thickness,lightweight construction,flexibility,exceptional mechanical strength,and superior electrothermal and photothermal properties,particularly for flexible and wearable electronics.In this regard,we designed an absorption-based composite film comprising carbon nanotubes(CNT)and α-Fe_(2)O_(3),featuring a CNT layer sandwiched between twoα-Fe_(2)O_(3)layers on the upper and lower surfaces.This composite film was fabricated through an electrodeposition process followed by a thermal annealing procedure to achieve enhanced EMI shielding performance along with improved electrothermal and photothermal properties.The strategically designed sandwich structure allows the rough surface of the upper α-Fe_(2)O_(3)layer to not only improve the impedance mismatch between free space and the composite film,facilitating the penetration of incident electromagnetic(EM)waves into the film and promoting increased EM absorption rather than reflection,but also to enhance electrical conductivity,thereby improving electron mobility and density.Consequently,the average total shielding effectiveness(SE)of the CNT/Fe_(16)-300 composite demonstrates remarkable EMI shielding effectiveness(EMI SE:56.8 dB).Furthermore,the alteration in the absorption-to-reflection ratio(A/R)signifies a transition in the EMI shielding mechanism from reflection(0.69 for the pristine CNT film)to absorption(1.86 for the CNT/Fe_(16)-300)with the incremental deposition of α-Fe_(2)O_(3)nanoparticles.This work presents a feasible manufacturing approach for developing composite films with a sandwich structure that exhibits absorption-dominant EMI shielding capabilities,contributing to advancements in thermal management and multifunctional electromagnetic shielding applications.展开更多
In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The...In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The microstructures,XRD patterns,FTIR spectra,UV-Vis-NIR spectra thermo-conductivity,thermo-stability and photothermal effects of these composite films were all characterized.These results indicated that Ti_(2)O_(3) particles were well dispersed throughout the polyvinyl alcohol(PVA)matrix in the PVA/Ti_(2)O_(3) composite films.And Ti_(2)O_(3) particles could also effectively improve the photothermal properties of the composite films which exhibited high light absorption and generated a high temperature(about 57.4℃for film with 15 wt%Ti_(2)O_(3) amount)on the surface when it was irradiated by a simulated sunlight source(1 kW/m^(2)).展开更多
Tetravalent tin(Sn4+)-based inorganic perovskite semiconductors like Cs_(2)SnI_(6)are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendlines...Tetravalent tin(Sn4+)-based inorganic perovskite semiconductors like Cs_(2)SnI_(6)are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendliness.In this paper,we reported the dopant compensation effect in the component-dependent self-doped(111)-oriented Cs_(2)SnI_(6)thin films grown with pulsed laser deposition(PLD)at room temperature.The films were grown on(100)-SrTiO_(3)(STO)substrates at room temperature by PLD.Hall results of the Cs_(2)SnI_(6)films with different components realizing by controlling the ratio of SnI_(4)/CsI in the targets demonstrate a clear change of conductivity type from N-type to P-type,while the carrier concentration decreases from 1018 to 1013 and accordingly the film resistivity increases significantly from 3.8 to 2506Ωcm.The defect-relatedopticalfingerprints of Cs_(2)SnI_(6)films werealsoinvestigated withtemperature-dependent photoluminescence spectroscopy.At low temperatures of 10 K,the Cs_(2)SnI_(6)films exhibit donor-bound(D^(0)X)and donor-acceptor pair(DAP)emission,respectively,due to the self-doping effect.These re-sults indicate that controlling the composition of the PLD target is a powerful way to tune the electrical properties of Cs_(2)SnI_(6)films for possible applications in solar cells or X-ray detectors.展开更多
The Ni-P/TiO2 composite film on sintered NdFeB permanent magnet was investigated by X-ray diffraction （XRD）,environmental scanning electron microscopy （ESEM）,and energy dispersive X-ray spectrometer （EDX）. The c...The Ni-P/TiO2 composite film on sintered NdFeB permanent magnet was investigated by X-ray diffraction （XRD）,environmental scanning electron microscopy （ESEM）,and energy dispersive X-ray spectrometer （EDX）. The corrosion resistance of Ni-P/TiO2 film coated on NdFeB magnet,in 0.5 mol/L NaCl solution,was studied by potentiodynamic polarization,salt spray test and electrochemical impedance spectroscopy （EIS） techniques. The self-corrosion current density （icorr） and the polarization resistance （Rp） of Ni-P/TiO2 film are 0.22 μA/cm2 （about 14% of that of Ni-P coating）,and 120 kΩ·cm2 （about 2 times of that of Ni-P coating）,respectively. The anti-salt spray time of Ni-P/TiO2 film is about 2.5 times of that of the Ni-P coating. The results indicate that Ni-P/TiO2 film has a better corrosion resistance than Ni-P coating,and the composite film increases the corrosion resistance of NdFeB magnet markedly.展开更多
ZrO2/TiO2 composite photocatalytic film was produced on the pure titanium substrate using in-situ Zr（OH）4 colloidal particle by the micro-arc oxidation technique and characterized by scanning electron microscope （...ZrO2/TiO2 composite photocatalytic film was produced on the pure titanium substrate using in-situ Zr（OH）4 colloidal particle by the micro-arc oxidation technique and characterized by scanning electron microscope （SEM）, energy dispersive X-ray （EDX）, X-ray diffraction （XRD） and ultraviolet-visible （UV-Vis） spectrophotometer. The composite film shows a lamellar and porous structure which consists of anatase, futile and ZrO2 phases. The optical absorption edge of film is shifted to longer wavelength when ZrO2 is introduced to TiO2. Furthermore, the photocatalytic reaction rate constants of degradation of rhodamine B solution with ZrO2/TiO2 composite film and pure TiO2 film under ultraviolet irradiation are measured as 0.0442 and 0.0186 h 1, respectively.展开更多
A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion...A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, ESEM （environmental scanning electron microscopy） and EIS （electrochemical impedance spectroscopy） measurements. Results showed that the NiP/ TiO2 composite film has a good corrosion resistance in 0.5mol/L H2SO4 solution. The element valence of the composite film was characterized by XPS （X-ray photoelectron spectroscopy） spectrum, and an anticorrosion mechanism of the composite film was discussed.展开更多
Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the ...Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n（Zn）/n（Ti） on the microstructures of TiO2-ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n（Zn）/n（Ti） typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n（Zn）/n（Ti） leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2-ZnO films reach the maximum and minimum at n（Zn）/n（Ti） of 1/9.3, respectively. The n（Zn）/n（Ti） shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n（Zn）/n（Ti） has influence on the amount of anatase/rutile TiO2 heterojunction in the film. With increase of the n（Zn）/n（Ti）, the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n（Zn）/n（Ti） but rather on the microstructures of the TiO2-ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n（Zn）/n（Ti）=1：9.3.展开更多
Total dose effects and single event effects on radiation-hardened power vertical double-diffusion metal oxide semiconductor（VDMOS） devices with composite SiO2-Si3N4 film gates are investigated.The relationships amon...Total dose effects and single event effects on radiation-hardened power vertical double-diffusion metal oxide semiconductor（VDMOS） devices with composite SiO2-Si3N4 film gates are investigated.The relationships among the important electrical parameters of the samples with different thickness SiO2-Si3N4 films,such as threshold voltage,breakdown voltage,and on-state resistance in accumulated dose,are discussed.The total dose experiment results show that the breakdown voltage and the on-state resistance barely change with the accumulated dose.However,the relationships between the threshold voltages of the samples and the accumulated dose are more complex,and not only positively drift,but also negatively drift.At the end of the total dose experiment,we select the group of samples which have the smaller threshold voltage shift to carry out the single event effect studies.We find that the samples with appropriate thickness ratio SiO2-Si3N4 films have a good radiation-hardening ability.This method may be useful in solving both the SEGR and the total dose problems with the composite SiO2-Si3N4 films.展开更多
In the present work, structure changes during （SiO2） composites have been investigated systematically stretching of isotactic polypropylene （iPP） and iPP/silicon dioxide The or-form crystal structure of both iPP a...In the present work, structure changes during （SiO2） composites have been investigated systematically stretching of isotactic polypropylene （iPP） and iPP/silicon dioxide The or-form crystal structure of both iPP and iPP/SiO2 composites is destroyed and transforms into the mesophase as the samples are stretched at a low temperature （35℃）, while stretching at high temperatures （90℃ and 120℃） can restrain the appearance of defects and keep the perfection of crystal structure. FTIR results reveal that the stretching temperatures show no obvious difference of the effect on the orientation of pure iPP, however, the orientation of iPP/SiO2 composites is greatly changed by the tensile temperature. In the case of micron-sized SiO2 particles （average particle diameter d 〉 1 μm）, the orientation of the composites is lower than that of pure iPP at all stretching temperatures. The above results suggest that the stretching temperature and the SiO2 particle size have great influence on the structure variation and orientation behavior of iPP/SiO2 composites.展开更多
Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma s...Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.展开更多
This study focused on the development and characterization of TiO<sub>2</sub>-PES composite fibers with varying TiO<sub>2</sub> loading amounts using a phase inversion process. The resulting co...This study focused on the development and characterization of TiO<sub>2</sub>-PES composite fibers with varying TiO<sub>2</sub> loading amounts using a phase inversion process. The resulting composite fibers exhibited a sponge-like structure with embedded TiO<sub>2</sub> nanoparticles within a polymer matrix. Their photocatalytic performance for ammonia removal from aqueous solutions under UV-A light exposure was thoroughly investigated. The findings revealed that PeTi8 composite fibers displayed superior adsorption capacity compared to other samples. Moreover, the study explored the impact of pH, light intensity, and catalyst dosage on the photocatalytic degradation of ammonia. Adsorption equilibrium isotherms closely followed the Langmuir model, with the results indicating a correlation between qm values of 2.49 mg/g and the porous structure of the adsorbents. The research underscored the efficacy of TiO<sub>2</sub> composite fibers in the photocatalytic removal of aqueous under UV-A light. Notably, increasing the distance between the photocatalyst and the light source resulted in de-creased hydroxyl radical concentration, influencing photocatalytic efficiency. These findings contribute to our understanding of TiO<sub>2</sub> composite fibers as promising photocatalysts for ammonia removal in water treatment applications.展开更多
The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmissi...The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), BET surface area, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal, increase the hydroxyl content on the surface of TiO2 films, lower the contact angle for water on TiO, films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 photocatalytic composite thin films with the contact angle of 0((o) under bar) are obtained by the addition of 10%-20% SiO2 in mole fraction.展开更多
Hollow B–SiO2@TiO2 composites were prepared by the wet chemical deposition method starting from TiCl4 and hollow B–SiO2 microspheres.TiO2 layers composed of anatase TiO2 nanoparticles were coated on the surfaces of ...Hollow B–SiO2@TiO2 composites were prepared by the wet chemical deposition method starting from TiCl4 and hollow B–SiO2 microspheres.TiO2 layers composed of anatase TiO2 nanoparticles were coated on the surfaces of the hollow B–SiO2 microspheres probably through the formation of Ti—O—Si and Ti—O—B bonds.A great number of—OH groups were also present at the TiO2 coating layers.The presence of Ti—O—Si bonds and Ti—O—B bonds resulted in the formation of defects in the TiO2 coating layers,which decreased the band gap of the TiO2 coating layers to ca.3.0 eV and endowed the TiO2 coating layers with visible light absorption performance.The buoyancy hollow B–SiO2@TiO2 composites exhibited high photocatalytic activities for the degradation of ammonia-nitrogen and green algae.The conversion of ammonia-nitrogen reached 65%when the degradation of ammonia-nitrogen(43 mg·L-1 at pH value of 8)was catalyzed by the B–SiO2@TiO2(100:10)composite under the simulated solar light irradiation at 35°C for 660 min.The green algae(5 mg·L-1)were almost completely degraded over the B–SiO@TiO2(100:20)photocatalyst under the visible light irradiation at 35°C for 510 min.展开更多
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 （XR...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.展开更多
Supermacroporous composite cryogels embedded with SiO2 nanoparticles were prepared by radical cryogenic copolymerization of the reactive monomer mixture of acrylamide（AAm） and N,N-methylene-bis-acrylamide（MBAAm） c...Supermacroporous composite cryogels embedded with SiO2 nanoparticles were prepared by radical cryogenic copolymerization of the reactive monomer mixture of acrylamide（AAm） and N,N-methylene-bis-acrylamide（MBAAm） containing SiO2 nanoparticles（mass ratios of nanoparticles to the monomer AAm from 0.01 to 0.08） under the freezing-temperature variation condition in glass columns.The properties of these composite cryogels were measured.The height equivalent to theoretical plate（HETP） of the cryogel beds at different liquid flow rates was determined by residence time distribution（RTD） using tracer pulse-response method.The composite cryogel matrix embedded with the mass fraction of SiO2 nanoparticles of 0.02 presented the best properties and was employed in the following graft polymerization.Chromatographic process of lysozyme in the composite cryogel grafted with 2-acrylamido-2-methyl-1-propanesulfonic acid（AMPSA） was carried out to evaluate the protein breakthrough and elution characteristics.The chromatography can be carried out at relatively high superficial velocity,i.e.,15 cm·min-1,indicating the satisfactory mechanical strength due to the embedded nanoparticles.展开更多
Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films have important application values in the fields of 5G communication technology,wearable electronic devices and artifici...Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films have important application values in the fields of 5G communication technology,wearable electronic devices and artificial intelligence.In this work,Fe_(3)O_(4)/polyamic acid(PAA)nanofiber films are prepared by in-situ polymerization and electrospinning technology,and Ti_(3)C_(2)T_(x)nanosheets are deposited on the surface of the Fe_(3)O_(4)/PAA nanofiber films via vacuum-assisted filtration.Then,Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/polyimide(PI))composite films are obtained by thermal imidization.The two sides of the Janus films exhibit completely different properties.The Fe_(3)O_(4)/PI side has excellent hydrophobicity and insulation property,and the Ti_(3)C_(2)T_(x)side has hydrophilicity and terrific conductivity.When the mass fraction of Ti_(3)C_(2)T_(x)is 80 wt.%,the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite film has excellent EMI shielding performances and mechanical properties,with EMI shielding effectiveness,tensile strength and Young’s modulus reaching 66 dB,114.5 MPa and 5.8 GPa,respectively.At the same time,electromagnetic waves show different absorption shielding effectiveness(SEA)when incident from two sides of the Janus films.When the electromagnetic waves are incident from the Fe_(3)O_(4)/PI side,the SEA of the Janus film is 58 dB,much higher than that when the electromagnetic waves are incident from the Ti_(3)C_(2)T_(x)side(39 dB).In addition,the Ti_(3)C_(2)T_(x)side of the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite films also has excellent electrothermal and photothermal conversion performances.When the applied voltage is 4 V,the stable surface temperature reaches 108°C;when it is irradiated by simulated sunlight with power density of 200 mW/cm2,the stable surface temperature reaches 95℃.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52222202 and 51772310)Chinese Academy of Sciences Key Research Program of Frontier Sciences(No.QYZDY-SSWJSC031)Shanghai Pilot Program for Basic Research-Chinese Academy of Science,Shanghai Branch(No.JCYJ-SHFY-2021-001).
文摘To mitigate secondary electromagnetic pollution,there is an urgent need to develop absorption-dominant electromagnetic interference(EMI)shielding materials with low density,reduced thickness,lightweight construction,flexibility,exceptional mechanical strength,and superior electrothermal and photothermal properties,particularly for flexible and wearable electronics.In this regard,we designed an absorption-based composite film comprising carbon nanotubes(CNT)and α-Fe_(2)O_(3),featuring a CNT layer sandwiched between twoα-Fe_(2)O_(3)layers on the upper and lower surfaces.This composite film was fabricated through an electrodeposition process followed by a thermal annealing procedure to achieve enhanced EMI shielding performance along with improved electrothermal and photothermal properties.The strategically designed sandwich structure allows the rough surface of the upper α-Fe_(2)O_(3)layer to not only improve the impedance mismatch between free space and the composite film,facilitating the penetration of incident electromagnetic(EM)waves into the film and promoting increased EM absorption rather than reflection,but also to enhance electrical conductivity,thereby improving electron mobility and density.Consequently,the average total shielding effectiveness(SE)of the CNT/Fe_(16)-300 composite demonstrates remarkable EMI shielding effectiveness(EMI SE:56.8 dB).Furthermore,the alteration in the absorption-to-reflection ratio(A/R)signifies a transition in the EMI shielding mechanism from reflection(0.69 for the pristine CNT film)to absorption(1.86 for the CNT/Fe_(16)-300)with the incremental deposition of α-Fe_(2)O_(3)nanoparticles.This work presents a feasible manufacturing approach for developing composite films with a sandwich structure that exhibits absorption-dominant EMI shielding capabilities,contributing to advancements in thermal management and multifunctional electromagnetic shielding applications.
基金Funded by the Youth Backbone Teacher Training Plan in University of Henan Province(No.21220028)Science and Technology Research Project of Henan Province(No.242102321066)+2 种基金Natural Science Foundation of Henan Province(No.232300420312)Henan University of Technology Young Backbone Teacher Training Plan(No.21421260)the Innovation Training Program for College Students in Henan Province(No.202310463046)。
文摘In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The microstructures,XRD patterns,FTIR spectra,UV-Vis-NIR spectra thermo-conductivity,thermo-stability and photothermal effects of these composite films were all characterized.These results indicated that Ti_(2)O_(3) particles were well dispersed throughout the polyvinyl alcohol(PVA)matrix in the PVA/Ti_(2)O_(3) composite films.And Ti_(2)O_(3) particles could also effectively improve the photothermal properties of the composite films which exhibited high light absorption and generated a high temperature(about 57.4℃for film with 15 wt%Ti_(2)O_(3) amount)on the surface when it was irradiated by a simulated sunlight source(1 kW/m^(2)).
基金financially supported by the National Key Re-search and Development Program of China(No.2022YFC3700801)the Key R&D Program of Shandong Province,China(No.2024SFGC0102),the Jinan Bureau of Education(No.JNSX2023015)the Jinan Bureau of Science and Technology(No.202333042).
文摘Tetravalent tin(Sn4+)-based inorganic perovskite semiconductors like Cs_(2)SnI_(6)are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendliness.In this paper,we reported the dopant compensation effect in the component-dependent self-doped(111)-oriented Cs_(2)SnI_(6)thin films grown with pulsed laser deposition(PLD)at room temperature.The films were grown on(100)-SrTiO_(3)(STO)substrates at room temperature by PLD.Hall results of the Cs_(2)SnI_(6)films with different components realizing by controlling the ratio of SnI_(4)/CsI in the targets demonstrate a clear change of conductivity type from N-type to P-type,while the carrier concentration decreases from 1018 to 1013 and accordingly the film resistivity increases significantly from 3.8 to 2506Ωcm.The defect-relatedopticalfingerprints of Cs_(2)SnI_(6)films werealsoinvestigated withtemperature-dependent photoluminescence spectroscopy.At low temperatures of 10 K,the Cs_(2)SnI_(6)films exhibit donor-bound(D^(0)X)and donor-acceptor pair(DAP)emission,respectively,due to the self-doping effect.These re-sults indicate that controlling the composition of the PLD target is a powerful way to tune the electrical properties of Cs_(2)SnI_(6)films for possible applications in solar cells or X-ray detectors.
基金Sponsored by Hi-Tech Research and Development Program of China (2003AA305120)
文摘The Ni-P/TiO2 composite film on sintered NdFeB permanent magnet was investigated by X-ray diffraction （XRD）,environmental scanning electron microscopy （ESEM）,and energy dispersive X-ray spectrometer （EDX）. The corrosion resistance of Ni-P/TiO2 film coated on NdFeB magnet,in 0.5 mol/L NaCl solution,was studied by potentiodynamic polarization,salt spray test and electrochemical impedance spectroscopy （EIS） techniques. The self-corrosion current density （icorr） and the polarization resistance （Rp） of Ni-P/TiO2 film are 0.22 μA/cm2 （about 14% of that of Ni-P coating）,and 120 kΩ·cm2 （about 2 times of that of Ni-P coating）,respectively. The anti-salt spray time of Ni-P/TiO2 film is about 2.5 times of that of the Ni-P coating. The results indicate that Ni-P/TiO2 film has a better corrosion resistance than Ni-P coating,and the composite film increases the corrosion resistance of NdFeB magnet markedly.
基金Project(gf200901002)supported by the Open Research Fund of National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology of Nanchang Hangkong University,China
文摘ZrO2/TiO2 composite photocatalytic film was produced on the pure titanium substrate using in-situ Zr（OH）4 colloidal particle by the micro-arc oxidation technique and characterized by scanning electron microscope （SEM）, energy dispersive X-ray （EDX）, X-ray diffraction （XRD） and ultraviolet-visible （UV-Vis） spectrophotometer. The composite film shows a lamellar and porous structure which consists of anatase, futile and ZrO2 phases. The optical absorption edge of film is shifted to longer wavelength when ZrO2 is introduced to TiO2. Furthermore, the photocatalytic reaction rate constants of degradation of rhodamine B solution with ZrO2/TiO2 composite film and pure TiO2 film under ultraviolet irradiation are measured as 0.0442 and 0.0186 h 1, respectively.
文摘A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, ESEM （environmental scanning electron microscopy） and EIS （electrochemical impedance spectroscopy） measurements. Results showed that the NiP/ TiO2 composite film has a good corrosion resistance in 0.5mol/L H2SO4 solution. The element valence of the composite film was characterized by XPS （X-ray photoelectron spectroscopy） spectrum, and an anticorrosion mechanism of the composite film was discussed.
基金Project (2010JQ6008) supported by the Natural Science Foundation of Shaanxi Province,China
文摘Series of TiO 2-ZnO heterojunction composite films with different n（Zn）/n（Ti） ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n（Zn）/n（Ti） on the microstructures of TiO2-ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n（Zn）/n（Ti） typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n（Zn）/n（Ti） leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2-ZnO films reach the maximum and minimum at n（Zn）/n（Ti） of 1/9.3, respectively. The n（Zn）/n（Ti） shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n（Zn）/n（Ti） has influence on the amount of anatase/rutile TiO2 heterojunction in the film. With increase of the n（Zn）/n（Ti）, the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n（Zn）/n（Ti） but rather on the microstructures of the TiO2-ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n（Zn）/n（Ti）=1：9.3.
文摘Total dose effects and single event effects on radiation-hardened power vertical double-diffusion metal oxide semiconductor（VDMOS） devices with composite SiO2-Si3N4 film gates are investigated.The relationships among the important electrical parameters of the samples with different thickness SiO2-Si3N4 films,such as threshold voltage,breakdown voltage,and on-state resistance in accumulated dose,are discussed.The total dose experiment results show that the breakdown voltage and the on-state resistance barely change with the accumulated dose.However,the relationships between the threshold voltages of the samples and the accumulated dose are more complex,and not only positively drift,but also negatively drift.At the end of the total dose experiment,we select the group of samples which have the smaller threshold voltage shift to carry out the single event effect studies.We find that the samples with appropriate thickness ratio SiO2-Si3N4 films have a good radiation-hardening ability.This method may be useful in solving both the SEGR and the total dose problems with the composite SiO2-Si3N4 films.
基金financially supported by the National Natural Science Foundation of China (Nos. 51073004 and 21074141)the China National Funds for Distinguished Young Scientists (No. 50925313)
文摘In the present work, structure changes during （SiO2） composites have been investigated systematically stretching of isotactic polypropylene （iPP） and iPP/silicon dioxide The or-form crystal structure of both iPP and iPP/SiO2 composites is destroyed and transforms into the mesophase as the samples are stretched at a low temperature （35℃）, while stretching at high temperatures （90℃ and 120℃） can restrain the appearance of defects and keep the perfection of crystal structure. FTIR results reveal that the stretching temperatures show no obvious difference of the effect on the orientation of pure iPP, however, the orientation of iPP/SiO2 composites is greatly changed by the tensile temperature. In the case of micron-sized SiO2 particles （average particle diameter d 〉 1 μm）, the orientation of the composites is lower than that of pure iPP at all stretching temperatures. The above results suggest that the stretching temperature and the SiO2 particle size have great influence on the structure variation and orientation behavior of iPP/SiO2 composites.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 50842028 and 50972012)the National Basic Research Program of China (Grant No 2007CB613301)
文摘Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.
文摘This study focused on the development and characterization of TiO<sub>2</sub>-PES composite fibers with varying TiO<sub>2</sub> loading amounts using a phase inversion process. The resulting composite fibers exhibited a sponge-like structure with embedded TiO<sub>2</sub> nanoparticles within a polymer matrix. Their photocatalytic performance for ammonia removal from aqueous solutions under UV-A light exposure was thoroughly investigated. The findings revealed that PeTi8 composite fibers displayed superior adsorption capacity compared to other samples. Moreover, the study explored the impact of pH, light intensity, and catalyst dosage on the photocatalytic degradation of ammonia. Adsorption equilibrium isotherms closely followed the Langmuir model, with the results indicating a correlation between qm values of 2.49 mg/g and the porous structure of the adsorbents. The research underscored the efficacy of TiO<sub>2</sub> composite fibers in the photocatalytic removal of aqueous under UV-A light. Notably, increasing the distance between the photocatalyst and the light source resulted in de-creased hydroxyl radical concentration, influencing photocatalytic efficiency. These findings contribute to our understanding of TiO<sub>2</sub> composite fibers as promising photocatalysts for ammonia removal in water treatment applications.
基金This work was financially supported by the Foundation for University Key Teachers by the Ministry of Education, theKey Resear
文摘The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), BET surface area, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal, increase the hydroxyl content on the surface of TiO2 films, lower the contact angle for water on TiO, films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 photocatalytic composite thin films with the contact angle of 0((o) under bar) are obtained by the addition of 10%-20% SiO2 in mole fraction.
基金Supported by the National Natural Science Foundation of China(21506078).
文摘Hollow B–SiO2@TiO2 composites were prepared by the wet chemical deposition method starting from TiCl4 and hollow B–SiO2 microspheres.TiO2 layers composed of anatase TiO2 nanoparticles were coated on the surfaces of the hollow B–SiO2 microspheres probably through the formation of Ti—O—Si and Ti—O—B bonds.A great number of—OH groups were also present at the TiO2 coating layers.The presence of Ti—O—Si bonds and Ti—O—B bonds resulted in the formation of defects in the TiO2 coating layers,which decreased the band gap of the TiO2 coating layers to ca.3.0 eV and endowed the TiO2 coating layers with visible light absorption performance.The buoyancy hollow B–SiO2@TiO2 composites exhibited high photocatalytic activities for the degradation of ammonia-nitrogen and green algae.The conversion of ammonia-nitrogen reached 65%when the degradation of ammonia-nitrogen(43 mg·L-1 at pH value of 8)was catalyzed by the B–SiO2@TiO2(100:10)composite under the simulated solar light irradiation at 35°C for 660 min.The green algae(5 mg·L-1)were almost completely degraded over the B–SiO@TiO2(100:20)photocatalyst under the visible light irradiation at 35°C for 510 min.
基金financially supported by the National Natural Science Foundation of China (No.51301118)the Projects of International Cooperation in Shanxi (No.2014081002)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (No.2013108)
文摘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.
基金Supported by the National Natural Science Foundation of China（20876145） the Natural Science Foundation of Zhejiang Province（Y4080329）
文摘Supermacroporous composite cryogels embedded with SiO2 nanoparticles were prepared by radical cryogenic copolymerization of the reactive monomer mixture of acrylamide（AAm） and N,N-methylene-bis-acrylamide（MBAAm） containing SiO2 nanoparticles（mass ratios of nanoparticles to the monomer AAm from 0.01 to 0.08） under the freezing-temperature variation condition in glass columns.The properties of these composite cryogels were measured.The height equivalent to theoretical plate（HETP） of the cryogel beds at different liquid flow rates was determined by residence time distribution（RTD） using tracer pulse-response method.The composite cryogel matrix embedded with the mass fraction of SiO2 nanoparticles of 0.02 presented the best properties and was employed in the following graft polymerization.Chromatographic process of lysozyme in the composite cryogel grafted with 2-acrylamido-2-methyl-1-propanesulfonic acid（AMPSA） was carried out to evaluate the protein breakthrough and elution characteristics.The chromatography can be carried out at relatively high superficial velocity,i.e.,15 cm·min-1,indicating the satisfactory mechanical strength due to the embedded nanoparticles.
基金supports from the National Natural Science Foundation of China(Nos.U21A2093 and 51903145)Fundamental Research Funds for the Central Universities(No.D5000210627)+1 种基金Y.L.Z.would like to thank the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2021107)This work is also financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.
文摘Flexible multifunctional polymer-based electromagnetic interference(EMI)shielding composite films have important application values in the fields of 5G communication technology,wearable electronic devices and artificial intelligence.In this work,Fe_(3)O_(4)/polyamic acid(PAA)nanofiber films are prepared by in-situ polymerization and electrospinning technology,and Ti_(3)C_(2)T_(x)nanosheets are deposited on the surface of the Fe_(3)O_(4)/PAA nanofiber films via vacuum-assisted filtration.Then,Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/polyimide(PI))composite films are obtained by thermal imidization.The two sides of the Janus films exhibit completely different properties.The Fe_(3)O_(4)/PI side has excellent hydrophobicity and insulation property,and the Ti_(3)C_(2)T_(x)side has hydrophilicity and terrific conductivity.When the mass fraction of Ti_(3)C_(2)T_(x)is 80 wt.%,the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite film has excellent EMI shielding performances and mechanical properties,with EMI shielding effectiveness,tensile strength and Young’s modulus reaching 66 dB,114.5 MPa and 5.8 GPa,respectively.At the same time,electromagnetic waves show different absorption shielding effectiveness(SEA)when incident from two sides of the Janus films.When the electromagnetic waves are incident from the Fe_(3)O_(4)/PI side,the SEA of the Janus film is 58 dB,much higher than that when the electromagnetic waves are incident from the Ti_(3)C_(2)T_(x)side(39 dB).In addition,the Ti_(3)C_(2)T_(x)side of the Janus Ti_(3)C_(2)T_(x)-(Fe_(3)O_(4)/PI)composite films also has excellent electrothermal and photothermal conversion performances.When the applied voltage is 4 V,the stable surface temperature reaches 108°C;when it is irradiated by simulated sunlight with power density of 200 mW/cm2,the stable surface temperature reaches 95℃.
