Transparent zinc oxide(ZnO) thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations(0.3-1.2 M) using zinc acetate dehydrate [Zn(CH_3COO)_2&...Transparent zinc oxide(ZnO) thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations(0.3-1.2 M) using zinc acetate dehydrate [Zn(CH_3COO)_2·2H_2O] as precursor and isopropanol and monoethanolamine(MEA) as solvent and stabilizer, respectively. The molar ratio of zinc acetate dehydrate to MEA is 1.0. X-ray diffraction, ultraviolet-visible spectroscopy and photoluminescence spectroscopy are employed to investigate the effect of solution concentration on the structural and optical properties of the ZnO thin films. The obtained results of all thin films are discussed in detail and are compared with other experimental data.展开更多
This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & sil...This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.展开更多
A new hybrid organic-inorganic structure of FTO/TiO2/Se/HTL/Au based selenium solar cell has been fabricated through a low-cost spin-coating process in air. In this process, selenium is completely dissolved in hydrazi...A new hybrid organic-inorganic structure of FTO/TiO2/Se/HTL/Au based selenium solar cell has been fabricated through a low-cost spin-coating process in air. In this process, selenium is completely dissolved in hydrazine, to fk)rm a homogeneous precursor solution. After spin-coating the precursor solution on the TiO2 substrates, following by sintering at 200 ℃ for 5rain, a uniform selenium film with crystalline grains is formed. The selenium based solar cell exhibits an efficiency of 1.23% under AM1.5 illumination (100 mW.cm-2), short-circuit current density of 8 mA.cm 2, open-circuit voltage of 0.55 V, and fill factor of 0.37. Moreover, the device shows a stable ability with almost the same performance alter 60 days.展开更多
Dye-sensitized solar cells (DSSCs) with ZnO spin-coated TiO2 photo-electrodes are compared to DSSC with a bare TiO2 photo-electrode. It is demonstrated that the deposited ZnO of controlled amount, by varying the precu...Dye-sensitized solar cells (DSSCs) with ZnO spin-coated TiO2 photo-electrodes are compared to DSSC with a bare TiO2 photo-electrode. It is demonstrated that the deposited ZnO of controlled amount, by varying the precursor concentration in the coating sol, can indeed enhance the performance of the DSSC. The measured power conversion efficiency shows a maximum around the precursor concentration 0.1 M and falls down sharply to 0% beyond this point. The results are interpreted on the basis of two competing factors: At ZnO concentrations less than 0.1 M, the formation of an energy barrier increases the photocurrent by reducing the rate of interfacial back-recombination. At ZnO concentrations greater than 0.1 M, the screening of the TiO2 film by thicker ZnO layers decreases the photocurrent through the reduction of TiO2 dye-adsorption efficiency.展开更多
This paper is concerned with the improvement of dye-sensitized solar cell (DSSC) efficiency upon ZnO-coating of the TiO2 electrode. Sol-gel ZnO of controlled amount by varying the number of sol drops during spin-coati...This paper is concerned with the improvement of dye-sensitized solar cell (DSSC) efficiency upon ZnO-coating of the TiO2 electrode. Sol-gel ZnO of controlled amount by varying the number of sol drops during spin-coating is shown to increase the DSSC efficiency. The highest efficiency is obtained at a single sol drop with enhancement of 40%, while beyond this amount the efficiency falls down sharply to zero. Based on measured optical absorption spectra of the different dye-loaded electrodes, it is concluded that this amount of ZnO sol corresponds to the thinnest layer that can create the energy barrier to minimize the electron recombination rate without seriously affecting the dye adsorption efficiency of the TiO2 film.展开更多
Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current st...Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current strategy for building DESWs is to screen materials for composite or prepare plasmonic nanocrystal films.These rigorous preparation processes seriously limit the further development of DESWs.Herein,we report a facile and effective sol-gel strategy using a foaming agent to achieve porous Ti-doped tungsten oxide film for the high performance of DESWs.The introduction of foaming agent polyvinylpyrrolidone during the film preparation can increase the specific surface area and free carrier concentration of the films and enhance their independent regulation ability of near-infrared electrochromism.As a result,the optimal film shows excellent dual-band electrochromic properties,including high optical modulation(84.9%at 633 nm and 90.3%at 1200 nm),high coloration efficiency(114.9 cm^(2) C^(-1) at 633 nm and 420.3 cm^(2) C^(-1) at 1200 nm),quick switching time,excellent bistability,and good cycle stability(the transmittance modulation losses at 633 and 1200 nm were 11%and 3.5%respectively after 1000 cycles).A demonstrated DESW fabricated by the sol-gel film showed effective management of heat and light of sunlight.This study represents a significant advance in the preparation of dual-band electrochromic films,which will shed new light on advancing electrochromic technology for future energy-saving smart buildings.展开更多
Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with differ-ent Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-...Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with differ-ent Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Vis spectrophotometry and photoconductivity study. The variation observed in the properties of the measured films agrees with a difference in the film's thickness, which decreases when Al concentration augments. X-ray diffraction analysis reveals that all films are polycrystal-line with tetragonal structure, (110) plane being the strongest diffraction peak. The crystallite size calculated by the Debye Scher-rer’s formula decreases from 11.92 to 8.54 nm when Al concentration increases from 0 to 5 wt.%. AFM images showed grains uni-formly distributed in the deposited films. An average transmittance greater than 80% was measured for the films and an en-ergy gap value of about 3.9 eV was deduced from the optical analysis. Finally, the photosensitivity properties like current-voltage characteristics, ION/IOFF ratio, growth and decay time are studied and reported. Also, we have calculated the trap depth energy using the decay portion of the rise and decay curve photocurrent.展开更多
Multiferroic(BFO)nanoparticles doped with strontium with the general formula Bi1-xSrx FeO3(x=0,0.3,0.5,0.7)were synthesized using a modified sol-gel auto-combustion process.The structural,electrical,optical,and magnet...Multiferroic(BFO)nanoparticles doped with strontium with the general formula Bi1-xSrx FeO3(x=0,0.3,0.5,0.7)were synthesized using a modified sol-gel auto-combustion process.The structural,electrical,optical,and magnetic properties of the samples are discussed.The structural analysis,carried out using the x-ray powder diffraction technique,shows a structural transition from rhombohedral(R-3c)to cubic(Pm-3m)for the doping amount of strontium(Sr)equal to x=0.3.Morphological analysis of the prepared samples were carried out using scanning electron microscopy(SEM).Frequency-dependent dielectric constant and ac conductivity were studied.The doped samples,with improved dielectric properties,can be used to fabricate different optoelectronic devices.Strong dielectric dispersion and broad relaxation were exhibited by all the samples.Cole–Cole plots were employed as an effective tool to study the dispersion parameters,namely,the optical dielectric constant,static dielectric constant,relaxation time,and spreading factor.The activation energy was calculated from the relaxation peaks and Cole–Cole plots,which were found to be compatible with each other.The bandgap of the samples was calculated using diffuse reflectance spectral(DRS)analysis.Sharp and strong photoluminescence in the IR region was observed in the samples,similar to ZnO,which was reported for the first time.Room-temperature and low-temperature magnetization studies point towards the superparamagnetic nature of the samples,with an improvement in magnetic properties with doping.The antiferromagnetic behavior of bulk bismuth ferrite transforms to superparamagnetic in nature for both pure and Sr-substituted bismuth ferrite nanoparticles due to the close dimensions of crystallite size with magnetic domains leading to the break-down of the frustrated spin cycloidal moment.展开更多
To protect the AM60B magnesium alloy from corrosion,a sol-gel coating containing hydroxylated g-C_(3)N_(4)nanoplates was applied.The chemical composition of the hydroxylated g-C_(3)N_(4)nanoplates was investigated usi...To protect the AM60B magnesium alloy from corrosion,a sol-gel coating containing hydroxylated g-C_(3)N_(4)nanoplates was applied.The chemical composition of the hydroxylated g-C_(3)N_(4)nanoplates was investigated using X-ray photoelectron spectroscopy(XPS).The hydroxylation process did not affect the crystal size,specific surface area,pore volume,average pore diameter,and thermal stability of the g-C_(3)N_(4)nanoplates.After incorporating pristine and hydroxylated g-C_(3)N_(4)nanoplates,dense sol-gel coatings were obtained.Transmission electron microscopy(TEM)revealed the uniform distribution of the modified g-C_(3)N_(4)in the coating.The average roughness of the coating was also reduced after adding the modified nanoplates due to the decreased aggregation tendency.Electrochemical impedance spectroscopy(EIS)examinations in simulated acid rain revealed a significant improvement in the anticorrosion properties of the sol-gel film after the addition of the modified g-C_(3)N_(4)due to the chemical bonding of the coating to the nanoplates.展开更多
The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X...The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.展开更多
文摘Transparent zinc oxide(ZnO) thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations(0.3-1.2 M) using zinc acetate dehydrate [Zn(CH_3COO)_2·2H_2O] as precursor and isopropanol and monoethanolamine(MEA) as solvent and stabilizer, respectively. The molar ratio of zinc acetate dehydrate to MEA is 1.0. X-ray diffraction, ultraviolet-visible spectroscopy and photoluminescence spectroscopy are employed to investigate the effect of solution concentration on the structural and optical properties of the ZnO thin films. The obtained results of all thin films are discussed in detail and are compared with other experimental data.
文摘This paper concentrates on the development of glasses with self-cleaning surfaces exhibiting high water contact angles. In this study, we prepared super-hydrophobic nano-ceramic coated glass based on titania & silica using simple sol-gel & dip coating methods and studied the best composition of the coatings by altering ratios of titanium tetraisopropoxide (TTIP)/tetraethyl orthosilicate (TEOS) with different homogenizing agents. We characterized the coatings by surface roughness measurement, percentage of optical transmission, static contact angle, near-infrared (NIR) transmission, and diffuse reflectance. The fabrication of coatings on glass substrates played an important role in increasing the water contact angle of about 95° and visible & NIR transmission of about 90%. We compared our modified glass substrate with commercial low emissivity (Low E) glass using X-ray diffraction (XRD) analysis, which showed pure amorphous surface claiming excellent wettability and thus the prepared glass substrate could have a variety of applications in different fields.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51579057,5177090655,and 51379052)the State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology,China(Grant No.2016DX07)
文摘A new hybrid organic-inorganic structure of FTO/TiO2/Se/HTL/Au based selenium solar cell has been fabricated through a low-cost spin-coating process in air. In this process, selenium is completely dissolved in hydrazine, to fk)rm a homogeneous precursor solution. After spin-coating the precursor solution on the TiO2 substrates, following by sintering at 200 ℃ for 5rain, a uniform selenium film with crystalline grains is formed. The selenium based solar cell exhibits an efficiency of 1.23% under AM1.5 illumination (100 mW.cm-2), short-circuit current density of 8 mA.cm 2, open-circuit voltage of 0.55 V, and fill factor of 0.37. Moreover, the device shows a stable ability with almost the same performance alter 60 days.
文摘Dye-sensitized solar cells (DSSCs) with ZnO spin-coated TiO2 photo-electrodes are compared to DSSC with a bare TiO2 photo-electrode. It is demonstrated that the deposited ZnO of controlled amount, by varying the precursor concentration in the coating sol, can indeed enhance the performance of the DSSC. The measured power conversion efficiency shows a maximum around the precursor concentration 0.1 M and falls down sharply to 0% beyond this point. The results are interpreted on the basis of two competing factors: At ZnO concentrations less than 0.1 M, the formation of an energy barrier increases the photocurrent by reducing the rate of interfacial back-recombination. At ZnO concentrations greater than 0.1 M, the screening of the TiO2 film by thicker ZnO layers decreases the photocurrent through the reduction of TiO2 dye-adsorption efficiency.
文摘This paper is concerned with the improvement of dye-sensitized solar cell (DSSC) efficiency upon ZnO-coating of the TiO2 electrode. Sol-gel ZnO of controlled amount by varying the number of sol drops during spin-coating is shown to increase the DSSC efficiency. The highest efficiency is obtained at a single sol drop with enhancement of 40%, while beyond this amount the efficiency falls down sharply to zero. Based on measured optical absorption spectra of the different dye-loaded electrodes, it is concluded that this amount of ZnO sol corresponds to the thinnest layer that can create the energy barrier to minimize the electron recombination rate without seriously affecting the dye adsorption efficiency of the TiO2 film.
基金supported by the National Natural Science Foundation of China(51902064)the Natural Science Foundation of Guangxi(2022GXNSFFA0350325)+2 种基金the Scientific and Technological Bases and Talents of Guangxi(Guike AD20159073)the special fund for“Guangxi Bagui Scholars”the“Guangxi HundredTalent Program”。
文摘Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current strategy for building DESWs is to screen materials for composite or prepare plasmonic nanocrystal films.These rigorous preparation processes seriously limit the further development of DESWs.Herein,we report a facile and effective sol-gel strategy using a foaming agent to achieve porous Ti-doped tungsten oxide film for the high performance of DESWs.The introduction of foaming agent polyvinylpyrrolidone during the film preparation can increase the specific surface area and free carrier concentration of the films and enhance their independent regulation ability of near-infrared electrochromism.As a result,the optimal film shows excellent dual-band electrochromic properties,including high optical modulation(84.9%at 633 nm and 90.3%at 1200 nm),high coloration efficiency(114.9 cm^(2) C^(-1) at 633 nm and 420.3 cm^(2) C^(-1) at 1200 nm),quick switching time,excellent bistability,and good cycle stability(the transmittance modulation losses at 633 and 1200 nm were 11%and 3.5%respectively after 1000 cycles).A demonstrated DESW fabricated by the sol-gel film showed effective management of heat and light of sunlight.This study represents a significant advance in the preparation of dual-band electrochromic films,which will shed new light on advancing electrochromic technology for future energy-saving smart buildings.
基金support of the laboratory of active components and materials,Oum El Bouaghi University.
文摘Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with differ-ent Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Vis spectrophotometry and photoconductivity study. The variation observed in the properties of the measured films agrees with a difference in the film's thickness, which decreases when Al concentration augments. X-ray diffraction analysis reveals that all films are polycrystal-line with tetragonal structure, (110) plane being the strongest diffraction peak. The crystallite size calculated by the Debye Scher-rer’s formula decreases from 11.92 to 8.54 nm when Al concentration increases from 0 to 5 wt.%. AFM images showed grains uni-formly distributed in the deposited films. An average transmittance greater than 80% was measured for the films and an en-ergy gap value of about 3.9 eV was deduced from the optical analysis. Finally, the photosensitivity properties like current-voltage characteristics, ION/IOFF ratio, growth and decay time are studied and reported. Also, we have calculated the trap depth energy using the decay portion of the rise and decay curve photocurrent.
基金Project supported by the Support from DST, Govt of India for the FIST grant sanctioned to Vimala College Thrissur (Grant No. SR/FST/College-046/2011)Sultan Qaboos University for the support provided during this study
文摘Multiferroic(BFO)nanoparticles doped with strontium with the general formula Bi1-xSrx FeO3(x=0,0.3,0.5,0.7)were synthesized using a modified sol-gel auto-combustion process.The structural,electrical,optical,and magnetic properties of the samples are discussed.The structural analysis,carried out using the x-ray powder diffraction technique,shows a structural transition from rhombohedral(R-3c)to cubic(Pm-3m)for the doping amount of strontium(Sr)equal to x=0.3.Morphological analysis of the prepared samples were carried out using scanning electron microscopy(SEM).Frequency-dependent dielectric constant and ac conductivity were studied.The doped samples,with improved dielectric properties,can be used to fabricate different optoelectronic devices.Strong dielectric dispersion and broad relaxation were exhibited by all the samples.Cole–Cole plots were employed as an effective tool to study the dispersion parameters,namely,the optical dielectric constant,static dielectric constant,relaxation time,and spreading factor.The activation energy was calculated from the relaxation peaks and Cole–Cole plots,which were found to be compatible with each other.The bandgap of the samples was calculated using diffuse reflectance spectral(DRS)analysis.Sharp and strong photoluminescence in the IR region was observed in the samples,similar to ZnO,which was reported for the first time.Room-temperature and low-temperature magnetization studies point towards the superparamagnetic nature of the samples,with an improvement in magnetic properties with doping.The antiferromagnetic behavior of bulk bismuth ferrite transforms to superparamagnetic in nature for both pure and Sr-substituted bismuth ferrite nanoparticles due to the close dimensions of crystallite size with magnetic domains leading to the break-down of the frustrated spin cycloidal moment.
文摘To protect the AM60B magnesium alloy from corrosion,a sol-gel coating containing hydroxylated g-C_(3)N_(4)nanoplates was applied.The chemical composition of the hydroxylated g-C_(3)N_(4)nanoplates was investigated using X-ray photoelectron spectroscopy(XPS).The hydroxylation process did not affect the crystal size,specific surface area,pore volume,average pore diameter,and thermal stability of the g-C_(3)N_(4)nanoplates.After incorporating pristine and hydroxylated g-C_(3)N_(4)nanoplates,dense sol-gel coatings were obtained.Transmission electron microscopy(TEM)revealed the uniform distribution of the modified g-C_(3)N_(4)in the coating.The average roughness of the coating was also reduced after adding the modified nanoplates due to the decreased aggregation tendency.Electrochemical impedance spectroscopy(EIS)examinations in simulated acid rain revealed a significant improvement in the anticorrosion properties of the sol-gel film after the addition of the modified g-C_(3)N_(4)due to the chemical bonding of the coating to the nanoplates.
基金financially supported by (i) Suranaree University of Technology,(ii) Thailand Science Research and Innovation,and (iii) National Science,Research and Innovation Fund(project codes 90464 and 160363)。
文摘The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.