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Yu X.,Sun Yat Sen University | Xu H.,Sun Yat Sen University | Xin L.,Sun Yat Sen University | Wang X.,Sun Yat Sen University | And 6 more authors.
Journal of Materials Chemistry A | Year: 2013

In this study, we report a facile one-step solvothermal approach for growing nanoparticle aggregates-texture nanosheets hierarchical TiO2 core-shell structure (HTCSS) via the synergistic interaction of butylamine and ethanol. Under specific conditions, the products obtained in ethanol tended to aggregate into spherical structures, but in butylamine preferred to form nanosheet structures. Optimal cooperation between butylamine and ethanol leads to the formation of a core-shell structure with nanoparticle aggregates as the core and texture nanosheets as the shell. The HTCSSs cover a wide radius range from 150 to 800 nm, which is comparable to the wavelength of visible light. Therefore, they can be effectively used as light scattering materials to improve light harvesting in dye-sensitized solar cells (DSCs). Furthermore, the HTCSSs possess a very high surface area of 228.5 m2 g-1 and main pore size centered at 2.0 nm. DSCs using HTCSSs with bifunctional character of light scattering and high surface area properties showed an photoconversion efficiency of 8.90% under AM1.5 illumination, which was much higher than that derived from P25 nanoparticles of an optimized film thickness (6.09%). © 2013 The Royal Society of Chemistry. Source

Wang Y.,Hong Kong Polytechnic University | Yang H.,Hong Kong Polytechnic University | Xu H.,Institute for Solar Energy Systems
Materials Letters | Year: 2010

This paper reports a two-step formation of a TiO2 nanowire-covered nanotube bilayer film technique and its application in DNA-like dye-sensitized solar cells. The bilayer film was prepared by the electrochemical anodization first and then the hydrothermal method. From the reflectivity spectrum and scanning electron microscopy it is observed that the nanowire layer on the top cannot only decrease the reflectivity of the film, but also play a role to modify the film cracks. Compared with the dye-sensitized solar cells based on a single layer electrode, the cell with the bilayer film showed higher photovoltaic parameters and a lower dark current, which is due to its higher light harvesting efficiency and lower charge recombination between the electrolyte and the substrates. © 2009 Elsevier B.V. All rights reserved. Source

Wang Y.,Institute for Solar Energy Systems | Wang Y.,Hong Kong Polytechnic University | Liu Y.,Institute for Solar Energy Systems | Yang H.,Hong Kong Polytechnic University | And 4 more authors.
Current Applied Physics | Year: 2010

This paper reports a 3D DNA-like structured dye-sensitized solar cell (DSSC) with all-Ti substrates. A self-organized TiO2 nanotubular arrays layer was directly grown on the photoanode surface by electrochemical anodization. Compared with the traditional flat-type DSSC, the DNA-like DSSC showed superiority of light utilization due to its symmetrical double-helix structure. Different thickness of the nanotubular arrays layers were investigated to find their influence on the cell's photovoltaic parameters, and the cell with a 15.3 μm layer exhibited the highest Pmax, about 0.49 mW. The series-parallel connection characteristics of the DNA-like DSSCs reveal that the total voltage and the total short current equalled the sum of each cell's in series and in parallel, respectively. It is anticipated that the novel DNA-like structured DSSCs have great application potential in larger modules using integrated circuit. © 2009. Source

Liao Z.H.,Institute for Solar Energy Systems | Zhou J.X.,Institute for Solar Energy Systems | Zhuang L.,Institute for Solar Energy Systems | Shen H.,Institute for Solar Energy Systems | And 2 more authors.
2011 International Conference on Consumer Electronics, Communications and Networks, CECNet 2011 - Proceedings | Year: 2011

The bare magnetic Mn0.5Zn0.5Fe2O 4 nanoparticles were prepared by the hydro-thermal method. The optimized preparation conditions were obtained by the orthogonal experiment. Crystal structure and the grain diameter of the particles were observed by X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM), and the Curie temperature of the bare particles and the performance of the magnetic moment of the particles at different temperatures were characterized by the Vibrating Sample Magnetometer (VSM). The bare particles were modified by the oleic acid, and the modification effect was verified by the Infrared Test (IR). Mn 0.5Zn0.5Fe2O4 thermal-sensitive magnetic ferrofluid with excellent performance were prepared by dissolving the modified particles in the kerosene carrier. The saturation magnetization could reach up to 278Gs and the Curie temperature is confirmed to be 322K, which indicates that the quality of the Mn0.5Zn0.5Fe 2O4 thermal-sensitive ferrofluid is better than other Mn0.5Zn0.5Fe2O4 thermal-sensitive ferrofluids prepared by the coprecipitation method previously reported (Saturation magnetization: 150Gs, Curie temperature: 340K[1]). © 2011 IEEE. Source

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