2010 3rd International Nanoelectronics Conference (INEC), 2010
ABSTRACT Herein, a novel and facile method for preparing highly water-soluble CdS nanoparticles h... more ABSTRACT Herein, a novel and facile method for preparing highly water-soluble CdS nanoparticles has been developed. Cadmium acetate dehydrate was mixed in thiourea solution, using ethylenediaminetetraacetic acid (EDTA) as complexing agent. Electronic accelerator was used as radiation source. CdS nanoparticles were prepared rapidly at room temperature under atmospheric pressure without any kind of toxic reagents. Unlike those traditional routes, this method is facile and green, free of high temperature and toxic reagent. The prepared CdS nanoparticles had an average diameter about 3 nm. The product showed quantum confinement fluorescing in the blue region and dispersed in water well, which make it potentially using as fluorescent biomarkers. Meantime, the prepared CdS nanoparticles showed the photocatalytic activity to degrade organic pollutant.
A characteristic anti-restack 3D BiOCl hierarchitecture constructed by ultrathin BiOCl nanosheets... more A characteristic anti-restack 3D BiOCl hierarchitecture constructed by ultrathin BiOCl nanosheets assembled substructures has been designed and synthesized via a facile hydrothermal route. The graphene-like ultrathin BiOCl nanosheets with thickness of about 3.7 nm expose the renowned energetically active (0 0 1) facet, enabling the fast separation and transport of photogenerated electron-hole pairs. Meanwhile, the multi-reflection of light and large surface area of the formed 3D nano-velvet substructures enhance the light harvest and molecule adsorption capability. Consequently, the resultants show a superior photocatalytic performance of 99% photodegradation and corresponding 74% mineralization for rhodamine B within 10 min, and an outstanding photocurrent response under solar light illumination. What is more, the unique microstructure efficiently overcomes the restack of ultrathin nanosheets. This work develops a feasible strategy that utilizes ultrathin nanosheets to design and synthesize anti-restack hierarchitectures for establishing efficacious photocatalytic and water splitting systems.
Journal of the American Chemical Society, Jan 9, 2015
Organic Na-ion batteries (SIBs) are potential alternatives of current commercial inorganic Li-ion... more Organic Na-ion batteries (SIBs) are potential alternatives of current commercial inorganic Li-ion batteries for portable electronics (especially wearable electronics) because of their low cost and flexibility, making them possible to meet the future flexible and large-scale requirements. However, only a few organic SIBs have been reported so far and most of them either were tested in a very slow rate or suffered significant performance degradation when cycled under high rate. Here, we are focusing on the molecular design for improving the battery performance and addressing the current challenge of fast-charge and -discharge. Through reasonable molecular design strategy, we demonstrate that the ex-tension of the π-conjugated system is an efficient way to improve the high rate performance, leading to much enhanced capacity and cycleability with full recovery even after cycled under current density as high as 10 A/g.
ABSTRACT The growth control of AgTCNQ nanowire arrays is achieved by using a template-assisted el... more ABSTRACT The growth control of AgTCNQ nanowire arrays is achieved by using a template-assisted electro-deposition method. We find that the diffusion of the electrolyte into the nanopores plays an important role in the electro-deposition process, and an equilibrium between the reduction and diffusion is necessary to achieve continuous AgTCNQ nanowire arrays.
Solution processibility is one of the most intriguing properties of organic semiconductors. Howev... more Solution processibility is one of the most intriguing properties of organic semiconductors. However, it is difficult to find a suitable solvent and solution process for most semiconductors. For example, metal phthalocyanines (MPcs) are only soluble in non-volatile solvents, which prevent their applications from solution process. For the first time, vectorial diffusion is utilized for solution processing of MPcs. The obtained large F16CuPc and α-phase CuPc crystals and the efficient phase separation of them suggest the vectorial diffusion process is as slow as a self-assembly process, which is helpful to yield large crystals and purify the semiconductors. This method, which only uses common commercial solvents without any complex and expensive instruments and high-temperature operation, provides a facile approach for purification of organic semiconductors and growth of their crystals in large quantities.
Water-soluble orthorhombic colloidal SnSe quantum dots with an average diameter of 4nm were succe... more Water-soluble orthorhombic colloidal SnSe quantum dots with an average diameter of 4nm were successfully prepared by a novel irradiation route using an electronic accelerator as a radiation source and hexadecyl trimethyl ammonium bromide (CTAB) as a surfactant. The quantum dots exhibit a large direct bandgap of 3.89eV, greatly blue shifted compared with that of bulk SnSe (1.0eV) due to the quantum confinement effect. The quantum dots show blue photoluminescence at ∼420nm. The influence of CTAB on the growth of the quantum dots was investigated and a possible reaction/growth mechanism was proposed.
... 11, JG Zhou, C. Booker, RR Li, XT Zhou, TK Sham, XL Sun and ZF Ding, J. Am. Chem. ... 16, BR ... more ... 11, JG Zhou, C. Booker, RR Li, XT Zhou, TK Sham, XL Sun and ZF Ding, J. Am. Chem. ... 16, BR Selvi, D. Jagadeesan, BS Suma, G. Nagashankar, M. Arif, K. Balasubramanyam, M. Eswaramoorthy and TK Kundu, Nano Lett., 2008, 8, 31823188 Article ChemPort . ...
In this article, zinc oxide (ZnO) nanostructures of different shapes were fabricated on silicon s... more In this article, zinc oxide (ZnO) nanostructures of different shapes were fabricated on silicon substrate. Well-aligned and long ZnO nanowire (NW) arrays, as well as leaf-like ZnO nanostructures (which consist of modulated and single-phase structures), were fabricated by a chemical vapor deposition (CVD) method without the assistance of a catalyst. On the other hand, needle-like ZnO NW arrays were first fabricated with the CVD process followed by chemical etching of the NW arrays. The use of chemical etching provides a low-cost and convenient method of obtaining the needle-like arrays. In addition, the field emission properties of the different ZnO NW arrays were also investigated where some differences in the turn-on field and the field-enhancement factors were observed for the ZnO nanostructures of different lengths and shapes. It was experimentally observed that the leaf-like ZnO nanostructure is most suitable for field emission due to its lowest turn-on and threshold field as well as its high field-enhancement factor among the different synthesized nanostructures.
In this article, the important role of the intrinsic defects in size-controlled ZnO nanowires (NW... more In this article, the important role of the intrinsic defects in size-controlled ZnO nanowires (NWs) which play a critical role in the properties of the NWs, was studied with a combined innovative experimental analysis. The NWs prepared by both the aqueous solution method and chemical vapour deposition process were of increasing length and decreasing size-to-volume (S/V) ratio. The combined approach involved different analytical and spectroscopic techniques and from the correlation between the different measurements, the concentration of the oxygen vacancies jointly with the zinc interstitials defects and the zinc vacancy defects was observed to be positively or negatively correlated, respectively, with the magnitude of the photoluminescence intensity and radiative lifetimes. Furthermore, the experimental results also suggest that the oxygen vacancy defects are not only spatially located on the surface of the NW but an increasing fraction of the total oxygen vacancy defects connected with the green emission is also located in an annulus region beneath the surface as the ZnO NWs elongate. On the other hand, as the donor concentration plays a critical function in the properties of the ZnO NWs, an analytical model was derived for the calculation of the donor concentration of the NWs directly from its reverse-biased current-voltage characteristics obtained from the conductive atomic force microscopy measurements.
Size effects on formation energies and electronic structures of oxygen and zinc vacancies in ZnO ... more Size effects on formation energies and electronic structures of oxygen and zinc vacancies in ZnO nanowires: A first-principles study J. Appl. Phys. 109, 044306 (2011); 10.1063/1.3549131 O-vacancy-mediated spin-spin interaction in Co-doped ZnO: First-principles total-energy calculations
2010 3rd International Nanoelectronics Conference (INEC), 2010
ABSTRACT Herein, a novel and facile method for preparing highly water-soluble CdS nanoparticles h... more ABSTRACT Herein, a novel and facile method for preparing highly water-soluble CdS nanoparticles has been developed. Cadmium acetate dehydrate was mixed in thiourea solution, using ethylenediaminetetraacetic acid (EDTA) as complexing agent. Electronic accelerator was used as radiation source. CdS nanoparticles were prepared rapidly at room temperature under atmospheric pressure without any kind of toxic reagents. Unlike those traditional routes, this method is facile and green, free of high temperature and toxic reagent. The prepared CdS nanoparticles had an average diameter about 3 nm. The product showed quantum confinement fluorescing in the blue region and dispersed in water well, which make it potentially using as fluorescent biomarkers. Meantime, the prepared CdS nanoparticles showed the photocatalytic activity to degrade organic pollutant.
A characteristic anti-restack 3D BiOCl hierarchitecture constructed by ultrathin BiOCl nanosheets... more A characteristic anti-restack 3D BiOCl hierarchitecture constructed by ultrathin BiOCl nanosheets assembled substructures has been designed and synthesized via a facile hydrothermal route. The graphene-like ultrathin BiOCl nanosheets with thickness of about 3.7 nm expose the renowned energetically active (0 0 1) facet, enabling the fast separation and transport of photogenerated electron-hole pairs. Meanwhile, the multi-reflection of light and large surface area of the formed 3D nano-velvet substructures enhance the light harvest and molecule adsorption capability. Consequently, the resultants show a superior photocatalytic performance of 99% photodegradation and corresponding 74% mineralization for rhodamine B within 10 min, and an outstanding photocurrent response under solar light illumination. What is more, the unique microstructure efficiently overcomes the restack of ultrathin nanosheets. This work develops a feasible strategy that utilizes ultrathin nanosheets to design and synthesize anti-restack hierarchitectures for establishing efficacious photocatalytic and water splitting systems.
Journal of the American Chemical Society, Jan 9, 2015
Organic Na-ion batteries (SIBs) are potential alternatives of current commercial inorganic Li-ion... more Organic Na-ion batteries (SIBs) are potential alternatives of current commercial inorganic Li-ion batteries for portable electronics (especially wearable electronics) because of their low cost and flexibility, making them possible to meet the future flexible and large-scale requirements. However, only a few organic SIBs have been reported so far and most of them either were tested in a very slow rate or suffered significant performance degradation when cycled under high rate. Here, we are focusing on the molecular design for improving the battery performance and addressing the current challenge of fast-charge and -discharge. Through reasonable molecular design strategy, we demonstrate that the ex-tension of the π-conjugated system is an efficient way to improve the high rate performance, leading to much enhanced capacity and cycleability with full recovery even after cycled under current density as high as 10 A/g.
ABSTRACT The growth control of AgTCNQ nanowire arrays is achieved by using a template-assisted el... more ABSTRACT The growth control of AgTCNQ nanowire arrays is achieved by using a template-assisted electro-deposition method. We find that the diffusion of the electrolyte into the nanopores plays an important role in the electro-deposition process, and an equilibrium between the reduction and diffusion is necessary to achieve continuous AgTCNQ nanowire arrays.
Solution processibility is one of the most intriguing properties of organic semiconductors. Howev... more Solution processibility is one of the most intriguing properties of organic semiconductors. However, it is difficult to find a suitable solvent and solution process for most semiconductors. For example, metal phthalocyanines (MPcs) are only soluble in non-volatile solvents, which prevent their applications from solution process. For the first time, vectorial diffusion is utilized for solution processing of MPcs. The obtained large F16CuPc and α-phase CuPc crystals and the efficient phase separation of them suggest the vectorial diffusion process is as slow as a self-assembly process, which is helpful to yield large crystals and purify the semiconductors. This method, which only uses common commercial solvents without any complex and expensive instruments and high-temperature operation, provides a facile approach for purification of organic semiconductors and growth of their crystals in large quantities.
Water-soluble orthorhombic colloidal SnSe quantum dots with an average diameter of 4nm were succe... more Water-soluble orthorhombic colloidal SnSe quantum dots with an average diameter of 4nm were successfully prepared by a novel irradiation route using an electronic accelerator as a radiation source and hexadecyl trimethyl ammonium bromide (CTAB) as a surfactant. The quantum dots exhibit a large direct bandgap of 3.89eV, greatly blue shifted compared with that of bulk SnSe (1.0eV) due to the quantum confinement effect. The quantum dots show blue photoluminescence at ∼420nm. The influence of CTAB on the growth of the quantum dots was investigated and a possible reaction/growth mechanism was proposed.
... 11, JG Zhou, C. Booker, RR Li, XT Zhou, TK Sham, XL Sun and ZF Ding, J. Am. Chem. ... 16, BR ... more ... 11, JG Zhou, C. Booker, RR Li, XT Zhou, TK Sham, XL Sun and ZF Ding, J. Am. Chem. ... 16, BR Selvi, D. Jagadeesan, BS Suma, G. Nagashankar, M. Arif, K. Balasubramanyam, M. Eswaramoorthy and TK Kundu, Nano Lett., 2008, 8, 31823188 Article ChemPort . ...
In this article, zinc oxide (ZnO) nanostructures of different shapes were fabricated on silicon s... more In this article, zinc oxide (ZnO) nanostructures of different shapes were fabricated on silicon substrate. Well-aligned and long ZnO nanowire (NW) arrays, as well as leaf-like ZnO nanostructures (which consist of modulated and single-phase structures), were fabricated by a chemical vapor deposition (CVD) method without the assistance of a catalyst. On the other hand, needle-like ZnO NW arrays were first fabricated with the CVD process followed by chemical etching of the NW arrays. The use of chemical etching provides a low-cost and convenient method of obtaining the needle-like arrays. In addition, the field emission properties of the different ZnO NW arrays were also investigated where some differences in the turn-on field and the field-enhancement factors were observed for the ZnO nanostructures of different lengths and shapes. It was experimentally observed that the leaf-like ZnO nanostructure is most suitable for field emission due to its lowest turn-on and threshold field as well as its high field-enhancement factor among the different synthesized nanostructures.
In this article, the important role of the intrinsic defects in size-controlled ZnO nanowires (NW... more In this article, the important role of the intrinsic defects in size-controlled ZnO nanowires (NWs) which play a critical role in the properties of the NWs, was studied with a combined innovative experimental analysis. The NWs prepared by both the aqueous solution method and chemical vapour deposition process were of increasing length and decreasing size-to-volume (S/V) ratio. The combined approach involved different analytical and spectroscopic techniques and from the correlation between the different measurements, the concentration of the oxygen vacancies jointly with the zinc interstitials defects and the zinc vacancy defects was observed to be positively or negatively correlated, respectively, with the magnitude of the photoluminescence intensity and radiative lifetimes. Furthermore, the experimental results also suggest that the oxygen vacancy defects are not only spatially located on the surface of the NW but an increasing fraction of the total oxygen vacancy defects connected with the green emission is also located in an annulus region beneath the surface as the ZnO NWs elongate. On the other hand, as the donor concentration plays a critical function in the properties of the ZnO NWs, an analytical model was derived for the calculation of the donor concentration of the NWs directly from its reverse-biased current-voltage characteristics obtained from the conductive atomic force microscopy measurements.
Size effects on formation energies and electronic structures of oxygen and zinc vacancies in ZnO ... more Size effects on formation energies and electronic structures of oxygen and zinc vacancies in ZnO nanowires: A first-principles study J. Appl. Phys. 109, 044306 (2011); 10.1063/1.3549131 O-vacancy-mediated spin-spin interaction in Co-doped ZnO: First-principles total-energy calculations
Uploads
Papers by Yaoguo Fang