In this paper,we present our efforts on simulating and analyzing the effect of two-dimensional nano-sphere surface array on the characteristic of GaAs solar cells.Based on the scattering and diffraction theory of the ...In this paper,we present our efforts on simulating and analyzing the effect of two-dimensional nano-sphere surface array on the characteristic of GaAs solar cells.Based on the scattering and diffraction theory of the photonic crystals,the simulation results show that the distance of adjacent nano-spheres(D)has the pronounced influence on the conversion efficiency and exhibits much poor tolerance,the absolutely conversion efficiency is reduced by exceeding of 2%as the D varies from 0 to 1μm,in addition,the lower conversion efficiency(<18%)is exhibited and almost remains unaltered when the D is of>2μm.The radius(R)of nano-spheres demonstrates much great tolerance.For D=0,the solar cells exhibit high conversion efficiency(>20%)and the efficiency is only varied by less than 1%when R is varied in a very wide region of 0.3-1.2μm.One can also find out that there is good tolerance for efficiency around the optimal value of refractive index and there is only about 0.2%decrease in final cell efficiency for around±24%variation in the optimal values,which implys that it does not demand high precision processing equipment and the whole nano-sphere array could be fully complemented using self-assembled chemical methods.展开更多
Nano-structured photon management is currently an interesting topic since it can enhance the optical absorption and reduce the surface reflection which will improve the performance of many kinds of optoelectronic devi...Nano-structured photon management is currently an interesting topic since it can enhance the optical absorption and reduce the surface reflection which will improve the performance of many kinds of optoelectronic devices, such as Si-based solar cells and light emitting diodes. Here, we report the fabrication of periodically nano-patterned Si structures by using polystyrene nano-sphere lithography technique. By changing the diameter of nano-spheres and the dry etching parameters, such as etching time and etching power, the morphologies of formed Si nano-structures can be well controlled as revealed by atomic force microscopy.A good broadband antireflection property has been achieved for the formed periodically nano-patterned Si structures though they have the low aspect ratio(<0.53). The reflection can be significantly reduced compared with that of flat Si substrate in a wavelength range from 400 nm to 1200 nm. The weighted mean reflection under the AM1.5 solar spectrum irradiation can be as low as 3.92% and the corresponding optical absorption is significantly improved, which indicates that the present Si periodic nano-structures can be used in Si-based thin film solar cells.展开更多
In this work, electrospray technique combined sol-gel method was used to prepare porous TiO2 film. X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD), and Scanning Electron Microscope (SEM) analyses were ...In this work, electrospray technique combined sol-gel method was used to prepare porous TiO2 film. X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD), and Scanning Electron Microscope (SEM) analyses were conducted to examine the chemical composition, phase structure, and surface morphology of the sprayed TiO2 film. After calcined at 450℃ in air atmosphere for 2 h, mesoporous TiO2 nano-spheres clusters were formed on the surface of silicon wafer and the average size of nano-spheres was 250 nm. Ti presented as Ti 4+ oxidation state in TiO2 film, and the TiO2 film exhibited the anatase phase. The sprayed porous TiO2 films were employed as photocatalyst to degrade organic phosphorus in water samples. Compared with the TiO2 film prepared by Sol-Gel spin-coating method, the porous TiO2 film deposited by electrospray combined sol-gel method showed higher photocatalytic activity.展开更多
Here,we introduce a new p H-responsive optical nanosensor designed for precise detection and selective uptake of Pd^(2+)ions from wastewater and urban mining sites.Our approach focuses on creating silica nano-sphere m...Here,we introduce a new p H-responsive optical nanosensor designed for precise detection and selective uptake of Pd^(2+)ions from wastewater and urban mining sites.Our approach focuses on creating silica nano-sphere mesostructure-based nanosensor(MSNS-OYS)through a simple and reproducible synthesis method by directly immobilizing disodium 6-hydroxy-5-[(4-sulfonatophenyl)diazenyl]naphthalene-2-sulfonate(orange yellow S;OYS)chelate onto mesoporous silica nano-spheres(MSNS)carriers.We exploited the inherent surface properties and active acid sites of silica to facilitate stable interactions with the OYS chelate[OYS-Pd]^(n+),ensuring the integrity of the sensor during Pd^(2+)sensing assays as evidenced by N_(2)adsorption/desorption,FT-IR,SEM,HR-TEM,XPS,and elemental analyses.The nano-sized MSNS-OYS has large surface-tovolume ratios with a surface area of 686 m^(2)/g and a pore volume of 0.0925 cm^(3)/g.Adsorption capacity reaches 70.8 mg/g at pH 2.Fast mass transfer properties allow the equilibrium to be reached within 30 min.This method yields a sensitive sensor capable of detecting Pd^(2+)ions down to a limit of detection(LOD)of 11.6μg/L and a limit of quantification(LOQ)of 38.6μg/L,off ering stability,selectivity,and sensitivity.Additionally,the sensor can be easily regenerated by treatment with thiourea acidifi ed with 0.05 M HNO3.展开更多
Monodispersed ZnS nano-spheres were synthesized by a simple precipitation. By adjusting the concentration of Zn and S sources, the particle size and morphology were easily controlled. Careful examination of the obtain...Monodispersed ZnS nano-spheres were synthesized by a simple precipitation. By adjusting the concentration of Zn and S sources, the particle size and morphology were easily controlled. Careful examination of the obtained par- ticles suggested porous structures composed of building blocks of small crystallites, ca. 4-- 13.4 nm in diameter. A higher [S]/[Zn]-precursor ratio resulted in a bigger crystallite size but a smaller particle size, and vice versa, for the lower precursor ratio. However, an extreme [S]/[Zn] ratio of 20 provided no spherical aggregation, but a formation of amorphous aggregates. We consider the rate to nucleation and the diffusion-controlled aggregation of crystallites to be important parameters in determining particle sizes and size distributions. Size homogeneity of the obtained ZnS nano-spheres, especially with a [S]/[Zn]-precursor ratio of 5, afforded a photonic crystal array that can poten- tially benefit the photocatalytic activity. When the photocatalytic activities of the ZnS nano-spheres obtained via different conditions were compared, it was found that spherical aggregation and high surface areas have a positive effect on catalytic activity. Although using a [S]/[Zn] ratio of 20 provided the highest surface area, the amorphous aggregation and overly excessive use of S caused a detrimental influence on the catalytic activity.展开更多
ZnO micro-nano spheres covered with ZnO nanowires were synthesized at 650 ℃ without using cataly-sts. Characterizations of the products by TEM, SEM, XRD, SAED and EDS showed that the ZnO nanowires were of high purity...ZnO micro-nano spheres covered with ZnO nanowires were synthesized at 650 ℃ without using cataly-sts. Characterizations of the products by TEM, SEM, XRD, SAED and EDS showed that the ZnO nanowires were of high purity and single-crystalline with hexagonal wurtzite structure. The diameter of ZnO nanowires ranges from 60 to 200 nm and the length is longer than 10 μm. The size of the ZnO micro-nano spheres ranges from hundreds of nanometers to tens of microns. At the same time, the growth mechanism of ZnO micro-nano spheres is discussed.展开更多
基金National Nature Science Foundation of China(Grant No.61871350)Zhejiang Provincial Department of Education for their financial support of this research(Grant Nos.Y201121882 and Y201225406)
文摘In this paper,we present our efforts on simulating and analyzing the effect of two-dimensional nano-sphere surface array on the characteristic of GaAs solar cells.Based on the scattering and diffraction theory of the photonic crystals,the simulation results show that the distance of adjacent nano-spheres(D)has the pronounced influence on the conversion efficiency and exhibits much poor tolerance,the absolutely conversion efficiency is reduced by exceeding of 2%as the D varies from 0 to 1μm,in addition,the lower conversion efficiency(<18%)is exhibited and almost remains unaltered when the D is of>2μm.The radius(R)of nano-spheres demonstrates much great tolerance.For D=0,the solar cells exhibit high conversion efficiency(>20%)and the efficiency is only varied by less than 1%when R is varied in a very wide region of 0.3-1.2μm.One can also find out that there is good tolerance for efficiency around the optimal value of refractive index and there is only about 0.2%decrease in final cell efficiency for around±24%variation in the optimal values,which implys that it does not demand high precision processing equipment and the whole nano-sphere array could be fully complemented using self-assembled chemical methods.
基金supported by NSFC(Nos.61036001and 11274155)"973"pro ject(2013CB632101)NSF of Jiangsu Province(BK2010010)and PAPD
文摘Nano-structured photon management is currently an interesting topic since it can enhance the optical absorption and reduce the surface reflection which will improve the performance of many kinds of optoelectronic devices, such as Si-based solar cells and light emitting diodes. Here, we report the fabrication of periodically nano-patterned Si structures by using polystyrene nano-sphere lithography technique. By changing the diameter of nano-spheres and the dry etching parameters, such as etching time and etching power, the morphologies of formed Si nano-structures can be well controlled as revealed by atomic force microscopy.A good broadband antireflection property has been achieved for the formed periodically nano-patterned Si structures though they have the low aspect ratio(<0.53). The reflection can be significantly reduced compared with that of flat Si substrate in a wavelength range from 400 nm to 1200 nm. The weighted mean reflection under the AM1.5 solar spectrum irradiation can be as low as 3.92% and the corresponding optical absorption is significantly improved, which indicates that the present Si periodic nano-structures can be used in Si-based thin film solar cells.
基金Supported by the National Basic Research Program of China (No. 2009CB320300)National Natural Science Foundation of China (No. 61072023)National High Technology Research and Development Programs (No.2012AA040506, No. 2012AA101608)
文摘In this work, electrospray technique combined sol-gel method was used to prepare porous TiO2 film. X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD), and Scanning Electron Microscope (SEM) analyses were conducted to examine the chemical composition, phase structure, and surface morphology of the sprayed TiO2 film. After calcined at 450℃ in air atmosphere for 2 h, mesoporous TiO2 nano-spheres clusters were formed on the surface of silicon wafer and the average size of nano-spheres was 250 nm. Ti presented as Ti 4+ oxidation state in TiO2 film, and the TiO2 film exhibited the anatase phase. The sprayed porous TiO2 films were employed as photocatalyst to degrade organic phosphorus in water samples. Compared with the TiO2 film prepared by Sol-Gel spin-coating method, the porous TiO2 film deposited by electrospray combined sol-gel method showed higher photocatalytic activity.
基金funded by the University of JeddahJeddah+2 种基金Saudi Arabiaunder grant No.UJ-23-DR-155the University of Jeddah for its technical and financial support。
文摘Here,we introduce a new p H-responsive optical nanosensor designed for precise detection and selective uptake of Pd^(2+)ions from wastewater and urban mining sites.Our approach focuses on creating silica nano-sphere mesostructure-based nanosensor(MSNS-OYS)through a simple and reproducible synthesis method by directly immobilizing disodium 6-hydroxy-5-[(4-sulfonatophenyl)diazenyl]naphthalene-2-sulfonate(orange yellow S;OYS)chelate onto mesoporous silica nano-spheres(MSNS)carriers.We exploited the inherent surface properties and active acid sites of silica to facilitate stable interactions with the OYS chelate[OYS-Pd]^(n+),ensuring the integrity of the sensor during Pd^(2+)sensing assays as evidenced by N_(2)adsorption/desorption,FT-IR,SEM,HR-TEM,XPS,and elemental analyses.The nano-sized MSNS-OYS has large surface-tovolume ratios with a surface area of 686 m^(2)/g and a pore volume of 0.0925 cm^(3)/g.Adsorption capacity reaches 70.8 mg/g at pH 2.Fast mass transfer properties allow the equilibrium to be reached within 30 min.This method yields a sensitive sensor capable of detecting Pd^(2+)ions down to a limit of detection(LOD)of 11.6μg/L and a limit of quantification(LOQ)of 38.6μg/L,off ering stability,selectivity,and sensitivity.Additionally,the sensor can be easily regenerated by treatment with thiourea acidifi ed with 0.05 M HNO3.
文摘Monodispersed ZnS nano-spheres were synthesized by a simple precipitation. By adjusting the concentration of Zn and S sources, the particle size and morphology were easily controlled. Careful examination of the obtained par- ticles suggested porous structures composed of building blocks of small crystallites, ca. 4-- 13.4 nm in diameter. A higher [S]/[Zn]-precursor ratio resulted in a bigger crystallite size but a smaller particle size, and vice versa, for the lower precursor ratio. However, an extreme [S]/[Zn] ratio of 20 provided no spherical aggregation, but a formation of amorphous aggregates. We consider the rate to nucleation and the diffusion-controlled aggregation of crystallites to be important parameters in determining particle sizes and size distributions. Size homogeneity of the obtained ZnS nano-spheres, especially with a [S]/[Zn]-precursor ratio of 5, afforded a photonic crystal array that can poten- tially benefit the photocatalytic activity. When the photocatalytic activities of the ZnS nano-spheres obtained via different conditions were compared, it was found that spherical aggregation and high surface areas have a positive effect on catalytic activity. Although using a [S]/[Zn] ratio of 20 provided the highest surface area, the amorphous aggregation and overly excessive use of S caused a detrimental influence on the catalytic activity.
文摘ZnO micro-nano spheres covered with ZnO nanowires were synthesized at 650 ℃ without using cataly-sts. Characterizations of the products by TEM, SEM, XRD, SAED and EDS showed that the ZnO nanowires were of high purity and single-crystalline with hexagonal wurtzite structure. The diameter of ZnO nanowires ranges from 60 to 200 nm and the length is longer than 10 μm. The size of the ZnO micro-nano spheres ranges from hundreds of nanometers to tens of microns. At the same time, the growth mechanism of ZnO micro-nano spheres is discussed.
