Jiangfeng Gong

Direct synthesis and characterization of CdS nanobelts

A method to directly synthesize single crystalline CdS nanobelts has been developed. The advantages of the method in rapid synthesis within several minutes and catalyst free comparing to the previous method propose a potential avenue to the further practical device production and applications. The as-synthesized CdS nanobelts grow along the [100] crystalline direction with usually 500–2000nm in width and about tens to several hundred micrometers in length. Two luminescence peaks around 516 and 758nm in room-temperature photoluminescence spectrum are ascribed to the band-to-band and trap emission, respectively.

Multiform structures of SnO2 nanobelts

Multiform SnO2 microstructures were synthesized by a facile thermal evaporation of tin grains. The product was characterized with a variety of techniques to obtain the structural and optical information. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed a large percentage of acute angle zigzag nanobelts with perfectly periodic morphology. High resolution transmission electron microscopy (HRTEM) images and selected area electron diffraction (SAED) patterns revealed that the zigzag nanobelts were single crystalline and their zone axis was along the [010] crystal direction. The growth mechanism of zigzag nanobelts was proposed based on TEM characterization and thermodynamic analysis. The zigzag nanobelts were deduced to be formed by changing the growth direction from to [101] or vice versa. The photoluminescence (PL) spectroscopy of the nanobelts showed a broad and strong luminescence emission centred at 550?nm.

Controlled synthesis of ZnS nanocombs by self-evaporation using ZnS nanobelts as source and substrates

ZnS nanocombs were fabricated via a two-step growth method. By annealing Au coated ZnS nanobelts with the help of SnO2/C, comb-like nanostructures would be formed. In the absence of SnO2/C, Au coated ZnS nanobelts would be evaporated completely at the same temperature. As revealed by high resolution transmission microscopy, the growth direction of the ZnS nanobelts was [210] while that of the branches was [001], which epitaxially grew on the (00 ± 1) side surfaces of the ZnS nanobelts. Self-evaporation was used to explain the formation of the ZnS nanocombs. Photoluminescence spectrum reveals that the ZnS nanocombs had two emission bands at 570 and 635 nm.

Zinc nanoplates synthesized by a micro-jet under electron-beam irradiation

Zinc nanoplates with interesting shapes have been successfully synthesized by irradiating Zn/ZnS core/shell microballs with electron beams in a transmission electron microscope. The structure characterization reveals that the nanoplates present a wurtzite phase covered with a thin ZnO layer. A systematic study on the microballs has been performed and a formation mechanism for these nanoplates has been proposed. The e-beam radiation technique provides a novel approach for fabrication of novel nanostructured materials.

Fabrication of ZnS/SnO nanowire/nanosheet hierarchical nanoheterostructure and its photoluminescence properties

String-like ZnS/SnO nanowire/nanosheet hierarchical nanoheterostructures were synthesized by a two-stage vapor transport and condensation method. X-Ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to characterize and analyze the as-synthesized products. The results indicated that the synthesized products consisted of numerous rectangular single crystalline SnO nanosheets threaded by single crystalline ZnS nanowires. A growth mechanism for the growth of the string-like nanoheterostructures has been proposed. Room temperature photoluminescence properties of the nanostructures were investigated. Both the emissions from ZnS nanowires and SnO nanosheets were observed in the PL spectrum of the string-like nanoheterostructures. These special heterostructures may find applications in nanoelectronic and photonic devices.

Layered tin dioxide microrods

Single-crystalline layered SnO2 microrods were synthesized by a simple tin?water reaction at 900??C. The structural and optical properties of the sample were characterized by x-ray powder diffraction, energy-dispersive x-ray spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, Raman scattering and photoluminescence (PL) spectroscopy. High resolution transmission electron microscopy studies and selected area electron diffraction patterns revealed that the layered SnO2 microrods are single crystalline and their growth direction is along [1 1 0]. The growth mechanism of the microrods was proposed based on SEM, TEM characterization and thermodynamic analysis. It is deduced that the layered microrods grow by the stacking of SnO2 sheets with a (1?1?0) surface in a vapour?liquid?solid process. Three emission peaks at 523, 569 and 626?nm were detected in room-temperature PL measurements.

High-Performance Flexible In-Plane Micro-Supercapacitors Based on Vertically-Aligned CuSe@Ni(OH)2 Hybrid Nanosheet Films

The orientation and hybridization of ultrathin two-dimensional (2D) nanostructures on interdigital electrodes is vital for developing high-performance flexible in-plane micro-supercapacitors (MSCs). Despite great progress has been achieved, integrating CuSe and Ni(OH)2 nanosheets to generate advanced nanohybrids with oriented arrangement of each component and formation of porous frameworks remains a challenge, and their application for in-plane MSCs has not been explored. Herein, the vertically aligned CuSe@Ni(OH)2 hybrid nanosheet films with hierarchical open channels are skillfully deposited on Au interdigital electrodes/polyethylene terephthalate substrate via a template-free sequential electrodeposition approach, and directly employed to construct in-plane MSCs by choosing polyvinyl alcohol-LiCl gel as both the separator and the solid electrolyte. Because of the unique geometrical structure and combination of intrinsically conductive CuSe and battery-type Ni(OH)2 components, such hybrid nanosheet films can not only resolve the poor conductivity and re-stacking problems of Ni(OH)2 nanosheets but also create the 3D electrons or ions transport pathway. Thus, the in-plane MSCs device fabricated by such hybrid nanosheet films exhibits high volumetric specific capacitance (38.9 F cm-3). Moreover, its maximal energy and power density can reach 5.4 mW h cm-3 and 833.2 mW cm-3, superior to pure CuSe nanosheets, and most of reported carbon materials and metal hydroxides/oxides/sulfides based in-plane MSCs ones. Also, the hybrid nanosheet films device shows excellent cycling performance, good flexibility, and mechanical stability. This work may shed some light on optimizing 2D electrode materials and promote the development of flexible in-plane MSCs or other energy storage systems.