TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned Tit2 nanorod arrays （NRs） are grown on the fluorine-doped tin oxide （FTO） substrates by a multicycle hydr...TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned Tit2 nanorod arrays （NRs） are grown on the fluorine-doped tin oxide （FTO） substrates by a multicycle hydrothermal synthesis process. The samples are characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high-resolution transmission electron microscopy （HRTEM）, and selected-area electron diffraction （SAED）. It is found that dye-sensitized solar cells （DSSCs） assembled by the as-prepared Tit2 single-crystal NRs exhibit different trends under the condition of different nucleation and growth concentrations. Optimum cell performance is obtained with high nucleation concentration and low growth cycle concentration. The efficiency enhancement is mainly attributed to the improved specific surface area of the nanorod.展开更多
Single-crystalline tellurium nanorods were synthesized through the reduction of Na2TeO4 by hydrazine monohydrate, in the absence of surfactants, in an aqueous ammonia solution at room temperature. X-ray diffraction （...Single-crystalline tellurium nanorods were synthesized through the reduction of Na2TeO4 by hydrazine monohydrate, in the absence of surfactants, in an aqueous ammonia solution at room temperature. X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and selected area electron diffraction （SAED） were used to characterize the composition and morphology of the products. The concentration of the OH ion has a significant influence on the morphology of the products and is found to be responsible for tailoring the crystal growth dynamically： the concentration of Te blocking in the solution is reduced via increasing the concentration of the OH^- ion, and subsequently the nucleation rate of Te is suppressed and Te nanorods gradually grow because of the inherently anisotropic structure of Te. New generation tellurium atoms add to the surface of the particles during the long period of reaction.展开更多
Pure phase, regular shape and well crystallized nanorods of p-type semiconductor CaFeOhave been fabricated for the first time by a facile molten salt assisted method, as confirmed by XRD, TEM, SEM and HRTEM. UV-vis di...Pure phase, regular shape and well crystallized nanorods of p-type semiconductor CaFeOhave been fabricated for the first time by a facile molten salt assisted method, as confirmed by XRD, TEM, SEM and HRTEM. UV-vis diffuse reflectance spectra and Mott–Schottky plots show that the band structure of the CaFeOnanorods is narrower than that of the CaFeOnanoparticles synthesized by conventional method. The enhancement of the visible-light absorption is due to narrowness of the band gap in CaFeOnanorods. The appropriate ratio between the molten salt and the CaFeOprecursors plays an important role in inhibiting the growth of the crystals along the(201) plane to give the desired nanorod morphology. This work not only demonstrates that highly pure p-type CaFeOsemiconductor with tunable band structure and morphology could be obtained using the molten salt strategy, but also affirms that the bandgap of a semiconductor may be tunable by monitoring the growth of a particular crystal plane.Furthermore, the facile eutectic molten salt method developed in this work may be further extended to fabricate some other semiconductor nanomaterials with a diversity of morphologies.展开更多
A gain assisted double negative- Metallo-semiconductor photonic crystal （DN-MSPC） for visible light with effect of different plasmonic （Al, Ag, Au, Cu） nanorod inclusion, is presented. Negative real values of both...A gain assisted double negative- Metallo-semiconductor photonic crystal （DN-MSPC） for visible light with effect of different plasmonic （Al, Ag, Au, Cu） nanorod inclusion, is presented. Negative real values of both permeability （μ） and permittivity （ε） with extremely low imaginary values for visible light is obtained by applying Coupled dipole approximation. All-Angle negative refraction is obtained by applying surface plasmon polariton excitation （SPPE） in DN-MSPC operating in a dispersion regime with anti-parallel refracted wave vector and Poynting vector. Index matched to the incident light and compensated losses due the gain assistance leads the light amplification in the designed structure. Furthermore, extremely high left-handed transmission efficiency （〉99%） is also investigated. Demonstration of near and far-field resonance patterns reveal the nano-photonic device applications potential i.e. highly directional optical nanoantenna, filter, etc.展开更多
基金Project supported by the Fundamental Research Funds for the Central Universities,China(Grant No.2013XK07)
文摘TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned Tit2 nanorod arrays （NRs） are grown on the fluorine-doped tin oxide （FTO） substrates by a multicycle hydrothermal synthesis process. The samples are characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high-resolution transmission electron microscopy （HRTEM）, and selected-area electron diffraction （SAED）. It is found that dye-sensitized solar cells （DSSCs） assembled by the as-prepared Tit2 single-crystal NRs exhibit different trends under the condition of different nucleation and growth concentrations. Optimum cell performance is obtained with high nucleation concentration and low growth cycle concentration. The efficiency enhancement is mainly attributed to the improved specific surface area of the nanorod.
文摘Single-crystalline tellurium nanorods were synthesized through the reduction of Na2TeO4 by hydrazine monohydrate, in the absence of surfactants, in an aqueous ammonia solution at room temperature. X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and selected area electron diffraction （SAED） were used to characterize the composition and morphology of the products. The concentration of the OH ion has a significant influence on the morphology of the products and is found to be responsible for tailoring the crystal growth dynamically： the concentration of Te blocking in the solution is reduced via increasing the concentration of the OH^- ion, and subsequently the nucleation rate of Te is suppressed and Te nanorods gradually grow because of the inherently anisotropic structure of Te. New generation tellurium atoms add to the surface of the particles during the long period of reaction.
基金supports from the National Natural Science Foundation of China(nos.21473189 and21503100)the 973 National Basic Research Program of China(no.2014CB239401)the Natural Science Foundation of Jiangxi Province of China(no.20151BAB213010)
文摘Pure phase, regular shape and well crystallized nanorods of p-type semiconductor CaFeOhave been fabricated for the first time by a facile molten salt assisted method, as confirmed by XRD, TEM, SEM and HRTEM. UV-vis diffuse reflectance spectra and Mott–Schottky plots show that the band structure of the CaFeOnanorods is narrower than that of the CaFeOnanoparticles synthesized by conventional method. The enhancement of the visible-light absorption is due to narrowness of the band gap in CaFeOnanorods. The appropriate ratio between the molten salt and the CaFeOprecursors plays an important role in inhibiting the growth of the crystals along the(201) plane to give the desired nanorod morphology. This work not only demonstrates that highly pure p-type CaFeOsemiconductor with tunable band structure and morphology could be obtained using the molten salt strategy, but also affirms that the bandgap of a semiconductor may be tunable by monitoring the growth of a particular crystal plane.Furthermore, the facile eutectic molten salt method developed in this work may be further extended to fabricate some other semiconductor nanomaterials with a diversity of morphologies.
基金supported by the "TIFAC Centre of Relevance and Excellence in Fiber Optics and Optical Communication at Delhi College of Engineering,Delhi" through "Mission REACH" program of Technology Vision-2020,Government of India
文摘A gain assisted double negative- Metallo-semiconductor photonic crystal （DN-MSPC） for visible light with effect of different plasmonic （Al, Ag, Au, Cu） nanorod inclusion, is presented. Negative real values of both permeability （μ） and permittivity （ε） with extremely low imaginary values for visible light is obtained by applying Coupled dipole approximation. All-Angle negative refraction is obtained by applying surface plasmon polariton excitation （SPPE） in DN-MSPC operating in a dispersion regime with anti-parallel refracted wave vector and Poynting vector. Index matched to the incident light and compensated losses due the gain assistance leads the light amplification in the designed structure. Furthermore, extremely high left-handed transmission efficiency （〉99%） is also investigated. Demonstration of near and far-field resonance patterns reveal the nano-photonic device applications potential i.e. highly directional optical nanoantenna, filter, etc.
