In this study,the corrosion resistance and the stability of passive films on the laser melting depositionprocessed 316L austenitic stainless steel with varying CeO_(2)contents in the environment of proton exchange mem...In this study,the corrosion resistance and the stability of passive films on the laser melting depositionprocessed 316L austenitic stainless steel with varying CeO_(2)contents in the environment of proton exchange membrane fuel cells were investigated using a combination of electrochemical and microstructural analyses.The findings reveal that 316L austenitic stainless steel with 0.20 wt%CeO_(2)exhibits a superior corrosion resistance,primarily due to grain refinement,a high proportion of low-angle grain boundaries and low∑coincidence site lattice grain boundaries,as well as increased dislocation density.The addition of CeO_(2)optimizes the type and size of inclusions and exerts a drag effect on grain boundaries,promoting the refinement of grains in the laser melting deposition-processed 316L auste nitic stainless steel.Moreover,the combined effect of these factors provides more active sites for the formation of a dense passive film with fewer point defects.展开更多
Unique and various microstructures of titanium oxide(TiO_2 ) film including macroporous structure, chromatic veins and rings, have been easily fabricated by mist deposition method on silicon substrate with mild prepar...Unique and various microstructures of titanium oxide(TiO_2 ) film including macroporous structure, chromatic veins and rings, have been easily fabricated by mist deposition method on silicon substrate with mild preparation conditions. Rutile phase TiO_2 nanoparticles were directly used as starting material to prepare film and led to a simple preparation process. It was found that several different microstructures existed in the sample and changed with the varied positions from the center to the edge of the film when the concentration of the TiO_2 suspension is 0.06 mol/l, the deposition time is 30 min, the flow rate is 1 l/min and the temperature is150. The surface texturing shows apparent distinction as the concentration of the TiO_2 suspension decreased to 0.03 mol/l and 0.01 mol/l.展开更多
Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal an...Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal annealing. An enhanced photocatalytic activity under ultraviolet C （UVC, 266 nm） light irradiation is obtained compared with that of the pristine TNA, which is shown by the steady-state photoluminescence （PL） spectra. Furthermore, a distinct blue shift in the nanosecond time-resolved transient photoluminescence （NTRT-PL） spectra is observed. Such a phenomenon could be well explained by considering the competition between the surface photocatalytic process and the recombination of the photo-generated carriers. The enhanced UV photocatalytic activities of the Au-TNA composite are evaluated through photo-degradation of methyl orange （MO） in an aqueous solution with ultraviolet-visible absorption spectrometry. Our current work may provide a simple strategy to synthesize defect-related composite photocatalytic devices.展开更多
Copper sulfide thin films are deposited onto different substrates at room temperature using the thermal evaporation technique. X-ray diffraction spectra show that the film has an orthorhombicchalcocite （7-Cu2S） phas...Copper sulfide thin films are deposited onto different substrates at room temperature using the thermal evaporation technique. X-ray diffraction spectra show that the film has an orthorhombicchalcocite （7-Cu2S） phase. The atomic force microscopy images indicate that the film exhibits nanoparticles with an average size of nearly 44 nm. Specrtophotometric measurements for the transmittance and reflectance are carried out at normal incidence in a spectral wavelength range of 450 nm-2500 nm. The refractive index, n, as well as the absorption index, k is calculated. Some dispersion parameters are determined. The analyses of el and e2 reveal several absorption peaks. The analysis of the spectral behavior of the absorption coefficient, c~, in the absorption region reveals direct and indirect allowed transitions. The dark electrical resistivity is studied as a function of film thickness and temperature. Tellier＇s model is adopted for determining the mean free path and bulk resistance.展开更多
The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy...The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.展开更多
The Cu_(2)ZnSnS_(4)thin film was prepared by a facile solution method without vacuum environment and toxic substance.The formation mechanism of the film was studied by transmission electron microscopy(TEM),X-ray diffr...The Cu_(2)ZnSnS_(4)thin film was prepared by a facile solution method without vacuum environment and toxic substance.The formation mechanism of the film was studied by transmission electron microscopy(TEM),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and Raman scattering measurements.Through cyclic voltammetry and photo-electricity tests,the electrocatalytic activity of the prepared film as the counter electrode of dye-sensitizedsolar cell was also studied.The results show that the mixed precursor solution mainly consists of Cu2SnS3 nanoparticles and Zn ions.After 550°C annealing process on the precursor film prepared from the mixed solution,Cu_(2)ZnSnS_(4)thin film is obtained.Besides,itis found that the prepared Cu_(2)ZnSnS_(4)thin film has the electrocatalytic activity toward the redox reaction of I3?/I?and the dye-sensitized solar cell with the prepared Cu_(2)ZnSnS_(4)thin film as the counter electrode achieves the efficiency of 1.09%.展开更多
The formation of Ag clusters on titanium oxide （TiO2） nanoparticles was achieved by self-assembly process and calcination. The obtained nanoparticles were characterized by X-ray diffraction （XRD）, transmission ele...The formation of Ag clusters on titanium oxide （TiO2） nanoparticles was achieved by self-assembly process and calcination. The obtained nanoparticles were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and ultraviolet visible spectroscopy （UV-Vis）, and conventional techniques （XRD, TEM and UV-Vis） were used to identify Ag particles on the TiO2 surfaces. The results show that Ag-TiO2 particles can be applied to improve catalytic activity of the epoxidation of styrene oxides. Styrene oxide is the main product of catalytic reaction with H2O2 as the oxidant by using Ag-TiO2 nanoparticles as catalysts. High catalytic activitity of styrene oxide can be obtainable at 80 ℃. The reaction temperature, reaction time, the molar ratio of H2O2/styrene and solvent affect greatly the catalytic epoxidation of styrene.展开更多
The CulnSe2 absorber was synthesized by non-vacuum process with a simple and low-cost method, which fabricated absorber layer of thin-film solar cell. The extra amount of Se was added into the ink to help reduction of...The CulnSe2 absorber was synthesized by non-vacuum process with a simple and low-cost method, which fabricated absorber layer of thin-film solar cell. The extra amount of Se was added into the ink to help reduction of the oxide and solid Se fountain was used to provide Se atmosphere during the selenization progress. The influence of same factors was investigated, such as the time of reduction in H2, the time of selenization and the Se vapor pressure. The selenizaion, processed at 550 ℃ for 60 min with the Se vapor pressure at 1.90 kPa, resulted in high quality CulnSe2 layer with very good chemical composition.展开更多
A low cost spin coating route of fabricating CuInS2 polycrystalline thin films by reactive sintering method was put forward. The ink for spin coating was optimized by pre-reducing the precursor powders in hydrogen, wh...A low cost spin coating route of fabricating CuInS2 polycrystalline thin films by reactive sintering method was put forward. The ink for spin coating was optimized by pre-reducing the precursor powders in hydrogen, which turned the nanoparticle precursor powders from mixed sulfides into a mixture of CuInS2 and Cu-In metal alloys. The results of scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Raman spectra showed that this optimization could highly improve the performance of CuInS2 polycrystalline thin films, including higher packing density, less impurity phases, and better quality. The energy gap of optimized CuInS2 thin film was determined to be about 1.45 eV by absorption spectroscopy measurement.展开更多
Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room te...Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate （PMMA）, SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope （FE-SEM） investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35-47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route.展开更多
In this work, CaF_2:Ln^(3+)(Ln:Er,Er/Yb)/Nafion composite films were prepared using Nafion as modifications and matrices by dripping method. The composite films were characterized by Fourier transform infrared spectro...In this work, CaF_2:Ln^(3+)(Ln:Er,Er/Yb)/Nafion composite films were prepared using Nafion as modifications and matrices by dripping method. The composite films were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD) and scanning electron microscopy(SEM). Composite films are transparent and CaF_2:Ln^(3+)(Ln:Er,Er/Yb) nanoparticles are well dispersed in Nafion films.The thicknesses of CaF_2:Er^(3+)/Nafion and CaF_2:Er^(3+),Yb^(3+)/Nafion composite film are about 77 and 73 μm,respectively. The nanoparticles in composite film possess cubic phase. CaF_2:Er^(3+),Yb^(3+)/Nafion composite film has stronger characteristic emission of Er^(3+) around 1530 nm with full width at half-maximum(FWHM) of 73 nm and longer luminescence lifetimes of 22.04 μs(25.03%) and 100.77 μs(74.97%).展开更多
The Ag-TiO2 thin film has been prepared on glass substrate by sol-gel process . The structure and properties of the materials were studied by DTA , XRD, and EPR. The photocatalytic activity was examined by the photoca...The Ag-TiO2 thin film has been prepared on glass substrate by sol-gel process . The structure and properties of the materials were studied by DTA , XRD, and EPR. The photocatalytic activity was examined by the photocatalytic degradation of dichlorophos. The analysis results indicate that the photocatalytic activity of the Ag-TiO2 thin film is higher than that of pure TiO2 thin film. It is also influenced by the content of anatase and heating temperature . The ESR result shows that the Ag-TiO2 thin film has more hydroxide radicals than pure TiO2 thin film after illuminated by UV light.展开更多
TiO 2 nanoparticle film catalysts with different thicknesses were prepared by plasma enhanced chemical vapor deposition(PECVD) method and the surfaces were subsequently treated by TiCl 4 or O 2 plasma. Two kinds of Ti...TiO 2 nanoparticle film catalysts with different thicknesses were prepared by plasma enhanced chemical vapor deposition(PECVD) method and the surfaces were subsequently treated by TiCl 4 or O 2 plasma. Two kinds of TiO 2 films with different surface properties were obtained. Their surface microstructures and energy levels of surface states were tested by AFM, XRD, SPS. The photocatalytic activities of the catalysts were determined via photodegradation experiments of phenol. The results demonstrated that photocatalytic activities of samples whose surface was treated by O 2 plasma were greater than those treated by TiCl 4 plasma. Moreover, photodegradation ratio of phenol during the first hour catalyzed by 0.17 μm thickness TiO 2 nanoparticle film was greater than other samples. Especially, the difference of photocatalytic activities of TiO 2 nanoparticle films treated by TiCl 4 or O 2 plasma was respectively explained by energy band theory.展开更多
Ternary sphere-like Cu2 SnS3（CTS）semiconductor and 2D hexagonal sheets were synthesized via a simple solvothermal method using PVP as the surface ligand at two temperatures of 180 and 220 X.The structural,morphologi...Ternary sphere-like Cu2 SnS3（CTS）semiconductor and 2D hexagonal sheets were synthesized via a simple solvothermal method using PVP as the surface ligand at two temperatures of 180 and 220 X.The structural,morphological,and chemical compositions as well as optical properties of as-synthesized CTS particles were characterized using X-ray diffraction（XRD）,Raman spectroscopy,energy dispersive X-ray spectrometry（EDS）,field emission scanning electron microscopy（FESEM）,and UV-Vis spectroscopy.The size of sphere-like particles and the side length of hexagonal sheets were within the range of 120-140 nm and 500 nm-2 μm,respectively.FESEM,XRD,and EDS were analyzed to investigate the mechanism of the morphological evolution of CTS particles.CTS particles showed proliferation of Sn atomic ratio,which is strongly sensitive to reaction temperature and,highly affects the increase of band gap energy from 1.36 to 1.53 eV due to generation metal defects and formation SnS2-The optical analysis via the transmittance and reflectance reveals that the band-gap energy of dropcasted CTS thin films decreases after annealing due to grain growth and change of chemical compositions.Photo-responses of CTS nanocrystal thin films indicated a considerable increase in the conductivity of the films under light illumination.All these results showed the potential of these films for solar cell applications.展开更多
A new kind of nonmetallic nanosensors based on surface-enhanced Raman spectroscopy(SERS)have been successfully prepared by the assembly of α-Fe_(2)O_(3) nanoparticles(NPs)onto clean quartz surface via the cross-linke...A new kind of nonmetallic nanosensors based on surface-enhanced Raman spectroscopy(SERS)have been successfully prepared by the assembly of α-Fe_(2)O_(3) nanoparticles(NPs)onto clean quartz surface via the cross-linker of hexamethylene diisocyanate(HDI).The resultant substrates have been characterized by electron micrographs,which show that the α-Fe_(2)O_(3) NPs distribute on the modified surface uniformly with a monolayer or sub-monolayer structure.4-mercaptopyridine(4-Mpy)and 2-mercaptobenzothiazole(2-MBT)molecules have been used as SERS probes to estimate the detection efficiency of the α-Fe_(2)O_(3) thin films.The SERS experiments show that it is possible to record high quality SERS spectra from probe molecules on the α-Fe_(2)O_(3) thin films at sub-micromolar(<10^(–6) mol/L)concentration.These results indicate that the highly ordered,uniformly roughed,highly sensitive and low-cost α-Fe_(2)O_(3) thin films are excellent candidates for nonmetallic SERS-active nanosensors.展开更多
基金Project supported by National Natural Science Foundation of China(52071227)Central Government Guidance to Local Science and Technology Development(YDZJSK20231A046)Key Scientific Research Project in Shanxi Province(202102050201003,202102050201010)。
文摘In this study,the corrosion resistance and the stability of passive films on the laser melting depositionprocessed 316L austenitic stainless steel with varying CeO_(2)contents in the environment of proton exchange membrane fuel cells were investigated using a combination of electrochemical and microstructural analyses.The findings reveal that 316L austenitic stainless steel with 0.20 wt%CeO_(2)exhibits a superior corrosion resistance,primarily due to grain refinement,a high proportion of low-angle grain boundaries and low∑coincidence site lattice grain boundaries,as well as increased dislocation density.The addition of CeO_(2)optimizes the type and size of inclusions and exerts a drag effect on grain boundaries,promoting the refinement of grains in the laser melting deposition-processed 316L auste nitic stainless steel.Moreover,the combined effect of these factors provides more active sites for the formation of a dense passive film with fewer point defects.
基金supported by a Grant-in-Aid for Scientific Research on Innovative Areas "New Polymeric Materials Based on Element-Blocks (No. 2401)" (24102004) of The Ministry of Education, Culture, Sports, Science, and Technology, Japan
文摘Unique and various microstructures of titanium oxide(TiO_2 ) film including macroporous structure, chromatic veins and rings, have been easily fabricated by mist deposition method on silicon substrate with mild preparation conditions. Rutile phase TiO_2 nanoparticles were directly used as starting material to prepare film and led to a simple preparation process. It was found that several different microstructures existed in the sample and changed with the varied positions from the center to the edge of the film when the concentration of the TiO_2 suspension is 0.06 mol/l, the deposition time is 30 min, the flow rate is 1 l/min and the temperature is150. The surface texturing shows apparent distinction as the concentration of the TiO_2 suspension decreased to 0.03 mol/l and 0.01 mol/l.
基金supported by the National Natural Science Foundation of China(Grant No.11274082)the Shandong Excellent Young Scientist Research Award Fund Project,China(Grant No.BS2011CL002)
文摘Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal annealing. An enhanced photocatalytic activity under ultraviolet C （UVC, 266 nm） light irradiation is obtained compared with that of the pristine TNA, which is shown by the steady-state photoluminescence （PL） spectra. Furthermore, a distinct blue shift in the nanosecond time-resolved transient photoluminescence （NTRT-PL） spectra is observed. Such a phenomenon could be well explained by considering the competition between the surface photocatalytic process and the recombination of the photo-generated carriers. The enhanced UV photocatalytic activities of the Au-TNA composite are evaluated through photo-degradation of methyl orange （MO） in an aqueous solution with ultraviolet-visible absorption spectrometry. Our current work may provide a simple strategy to synthesize defect-related composite photocatalytic devices.
文摘Copper sulfide thin films are deposited onto different substrates at room temperature using the thermal evaporation technique. X-ray diffraction spectra show that the film has an orthorhombicchalcocite （7-Cu2S） phase. The atomic force microscopy images indicate that the film exhibits nanoparticles with an average size of nearly 44 nm. Specrtophotometric measurements for the transmittance and reflectance are carried out at normal incidence in a spectral wavelength range of 450 nm-2500 nm. The refractive index, n, as well as the absorption index, k is calculated. Some dispersion parameters are determined. The analyses of el and e2 reveal several absorption peaks. The analysis of the spectral behavior of the absorption coefficient, c~, in the absorption region reveals direct and indirect allowed transitions. The dark electrical resistivity is studied as a function of film thickness and temperature. Tellier＇s model is adopted for determining the mean free path and bulk resistance.
基金Funded by the National Natural Science Foundation of China (50672089)the Encouraging Foundation for the Scientific Research of the Excellent Young and Middleaged Scientists in Shandong Province(2006BS04034)
文摘The film forming behavior on the interface between air and hydrosol of Fe2O3 nanoparticles was investigated by the surface pressure-time isotherms, the surface pressure-trough area isotherms, Brewster angle microscopy and transmission electron microscopy. It is found that the freshly prepared hydrosol of Fe2O3 nanoparticles is not stable. The surface pressure increases with the aging time and finally approaches a constant, and the smaller the concentration is, the smaller the surface pressure is stabilized at and the shorter the time the hydrosol reaching stable needs. The surface pressure also increases with compression until collapsed, and the longer the hydrosol is aged, the higher the collapsing pressure is. A uniform and compact film composed of nanoparticles with an average diameter of about 2-3 nm on the air-hydrosol interface is observed by Brewster angle microscope and transmission electron microscope.
基金Projects(51204214,51272292,51222403)supported by the National Natural Science Foundation of China
文摘The Cu_(2)ZnSnS_(4)thin film was prepared by a facile solution method without vacuum environment and toxic substance.The formation mechanism of the film was studied by transmission electron microscopy(TEM),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and Raman scattering measurements.Through cyclic voltammetry and photo-electricity tests,the electrocatalytic activity of the prepared film as the counter electrode of dye-sensitizedsolar cell was also studied.The results show that the mixed precursor solution mainly consists of Cu2SnS3 nanoparticles and Zn ions.After 550°C annealing process on the precursor film prepared from the mixed solution,Cu_(2)ZnSnS_(4)thin film is obtained.Besides,itis found that the prepared Cu_(2)ZnSnS_(4)thin film has the electrocatalytic activity toward the redox reaction of I3?/I?and the dye-sensitized solar cell with the prepared Cu_(2)ZnSnS_(4)thin film as the counter electrode achieves the efficiency of 1.09%.
基金the Natural Science Foundation of Jiangsu Province(No.BK2011024)the Scientific Research Project of Chaohu College(No.XLZ-200902)
文摘The formation of Ag clusters on titanium oxide （TiO2） nanoparticles was achieved by self-assembly process and calcination. The obtained nanoparticles were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and ultraviolet visible spectroscopy （UV-Vis）, and conventional techniques （XRD, TEM and UV-Vis） were used to identify Ag particles on the TiO2 surfaces. The results show that Ag-TiO2 particles can be applied to improve catalytic activity of the epoxidation of styrene oxides. Styrene oxide is the main product of catalytic reaction with H2O2 as the oxidant by using Ag-TiO2 nanoparticles as catalysts. High catalytic activitity of styrene oxide can be obtainable at 80 ℃. The reaction temperature, reaction time, the molar ratio of H2O2/styrene and solvent affect greatly the catalytic epoxidation of styrene.
文摘The CulnSe2 absorber was synthesized by non-vacuum process with a simple and low-cost method, which fabricated absorber layer of thin-film solar cell. The extra amount of Se was added into the ink to help reduction of the oxide and solid Se fountain was used to provide Se atmosphere during the selenization progress. The influence of same factors was investigated, such as the time of reduction in H2, the time of selenization and the Se vapor pressure. The selenizaion, processed at 550 ℃ for 60 min with the Se vapor pressure at 1.90 kPa, resulted in high quality CulnSe2 layer with very good chemical composition.
文摘A low cost spin coating route of fabricating CuInS2 polycrystalline thin films by reactive sintering method was put forward. The ink for spin coating was optimized by pre-reducing the precursor powders in hydrogen, which turned the nanoparticle precursor powders from mixed sulfides into a mixture of CuInS2 and Cu-In metal alloys. The results of scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Raman spectra showed that this optimization could highly improve the performance of CuInS2 polycrystalline thin films, including higher packing density, less impurity phases, and better quality. The energy gap of optimized CuInS2 thin film was determined to be about 1.45 eV by absorption spectroscopy measurement.
文摘Anatase TiO2 sol was synthesized under mild conditions （75℃ and ambient pressure） by hydrolysis of titaniumn-butoxide in abundant acidic aqueous solution and subsequent reflux to enhance crystallization. At room temperature and in ambient atmosphere, crystalline TiO2 thin films were deposited on polymethylmethacrylate （PMMA）, SiO2-coated PMMA and SiO2-coated silicone rubber substrates from the as-prepared TiO2 sol by a dip-coating process. SiO2 layers prior to TiO2 thin films on polymer substrates could not only protect the substrates from the photocatalytic decomposition of the TiO2 thin films but also enhance the adhesion of the TiO2 thin films to the substrates. Field-emission type scanning electron microscope （FE-SEM） investigations revealed that the average particle sizes of the nanoparticles composing the TiO2 thin films were about 35-47 nm. The TiO2 thin films exhibited high photocatalytic activities in the degradation of reactive brilliant red dye X-3B in aqueous solution under aerated conditions. The preparation process of photocatalytic TiO2 thin films on the polymer substrates was quite simple and a low temperature route.
基金Project supported by Natural Science Basic Research Plan in Shaanxi Province of China(No.2018JM2021)Xi'an Science and Technology Plan Project(2016CXWL10,CXY1443WL21)Program of Education Department of Shaanxi Provincial Government(15JK2152)
文摘In this work, CaF_2:Ln^(3+)(Ln:Er,Er/Yb)/Nafion composite films were prepared using Nafion as modifications and matrices by dripping method. The composite films were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD) and scanning electron microscopy(SEM). Composite films are transparent and CaF_2:Ln^(3+)(Ln:Er,Er/Yb) nanoparticles are well dispersed in Nafion films.The thicknesses of CaF_2:Er^(3+)/Nafion and CaF_2:Er^(3+),Yb^(3+)/Nafion composite film are about 77 and 73 μm,respectively. The nanoparticles in composite film possess cubic phase. CaF_2:Er^(3+),Yb^(3+)/Nafion composite film has stronger characteristic emission of Er^(3+) around 1530 nm with full width at half-maximum(FWHM) of 73 nm and longer luminescence lifetimes of 22.04 μs(25.03%) and 100.77 μs(74.97%).
基金Funded by the National Natural Science Foundation of Chi-na(Project 5007216) and Technology Foundation of Ministry of Edu-cation in China (Project 9908)
文摘The Ag-TiO2 thin film has been prepared on glass substrate by sol-gel process . The structure and properties of the materials were studied by DTA , XRD, and EPR. The photocatalytic activity was examined by the photocatalytic degradation of dichlorophos. The analysis results indicate that the photocatalytic activity of the Ag-TiO2 thin film is higher than that of pure TiO2 thin film. It is also influenced by the content of anatase and heating temperature . The ESR result shows that the Ag-TiO2 thin film has more hydroxide radicals than pure TiO2 thin film after illuminated by UV light.
文摘TiO 2 nanoparticle film catalysts with different thicknesses were prepared by plasma enhanced chemical vapor deposition(PECVD) method and the surfaces were subsequently treated by TiCl 4 or O 2 plasma. Two kinds of TiO 2 films with different surface properties were obtained. Their surface microstructures and energy levels of surface states were tested by AFM, XRD, SPS. The photocatalytic activities of the catalysts were determined via photodegradation experiments of phenol. The results demonstrated that photocatalytic activities of samples whose surface was treated by O 2 plasma were greater than those treated by TiCl 4 plasma. Moreover, photodegradation ratio of phenol during the first hour catalyzed by 0.17 μm thickness TiO 2 nanoparticle film was greater than other samples. Especially, the difference of photocatalytic activities of TiO 2 nanoparticle films treated by TiCl 4 or O 2 plasma was respectively explained by energy band theory.
文摘Ternary sphere-like Cu2 SnS3（CTS）semiconductor and 2D hexagonal sheets were synthesized via a simple solvothermal method using PVP as the surface ligand at two temperatures of 180 and 220 X.The structural,morphological,and chemical compositions as well as optical properties of as-synthesized CTS particles were characterized using X-ray diffraction（XRD）,Raman spectroscopy,energy dispersive X-ray spectrometry（EDS）,field emission scanning electron microscopy（FESEM）,and UV-Vis spectroscopy.The size of sphere-like particles and the side length of hexagonal sheets were within the range of 120-140 nm and 500 nm-2 μm,respectively.FESEM,XRD,and EDS were analyzed to investigate the mechanism of the morphological evolution of CTS particles.CTS particles showed proliferation of Sn atomic ratio,which is strongly sensitive to reaction temperature and,highly affects the increase of band gap energy from 1.36 to 1.53 eV due to generation metal defects and formation SnS2-The optical analysis via the transmittance and reflectance reveals that the band-gap energy of dropcasted CTS thin films decreases after annealing due to grain growth and change of chemical compositions.Photo-responses of CTS nanocrystal thin films indicated a considerable increase in the conductivity of the films under light illumination.All these results showed the potential of these films for solar cell applications.
基金This work was supported by the Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.09KJD150002)Zhenjiang Science and Technology Bureau(No.GJ2006006)Jiangsu University High-grade Specialty Person Scientific Research Foundation(No.10JDG114).
文摘A new kind of nonmetallic nanosensors based on surface-enhanced Raman spectroscopy(SERS)have been successfully prepared by the assembly of α-Fe_(2)O_(3) nanoparticles(NPs)onto clean quartz surface via the cross-linker of hexamethylene diisocyanate(HDI).The resultant substrates have been characterized by electron micrographs,which show that the α-Fe_(2)O_(3) NPs distribute on the modified surface uniformly with a monolayer or sub-monolayer structure.4-mercaptopyridine(4-Mpy)and 2-mercaptobenzothiazole(2-MBT)molecules have been used as SERS probes to estimate the detection efficiency of the α-Fe_(2)O_(3) thin films.The SERS experiments show that it is possible to record high quality SERS spectra from probe molecules on the α-Fe_(2)O_(3) thin films at sub-micromolar(<10^(–6) mol/L)concentration.These results indicate that the highly ordered,uniformly roughed,highly sensitive and low-cost α-Fe_(2)O_(3) thin films are excellent candidates for nonmetallic SERS-active nanosensors.
