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ABSTRACT: Spherical-shaped Gd2O3:Pr3+ phosphor particles were prepared with different concentrations of Pr3+
using the urea homogeneous precipitation method. The resulting Gd2O3:Pr3+ phosphor particles were characterized by X-ray diffraction, field emission scanning electron microscope, and photoluminescence spectroscopy. The effects of the Pr3+ doping concentration on the luminescent properties of Gd2O3:Pr3+ phosphors were investigated. Photoluminescence measurements revealed the Gd2O3:1 %Pr3+ phosphor particles to have the strongest emission. The luminescence properties of Gd2O3:Pr3? particles are strongly affected by the phosphor crystallinity and X-ray diffraction measurements confirmed that the crystallinity of Gd2O3 cubic structure could be enhanced by increasing the firing temperature. The luminescent Gd2O3:Pr3+ phosphor particles have potential applications in areas, such as optical display systems, lamps and etc.
Journal of Sol-Gel Science and Technology 07/2012; · 1.63 Impact Factor
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ABSTRACT: We used Ti meshes for both the photoanodes and counter electrodes of dye-sensitized solar cells (DSSCs) to improve the flexibility and conductivity of the electrodes. These mesh type electrodes showed good transparency and high bendability when subjected to an external force. We demonstrated the advantages of cells using such electrodes compared to traditional transparent conducting oxide based electrodes and back side illuminated DSSCs, such as low sheet resistance, elevated photo-induced current and enhanced sunlight utilization. Nanotube layers of different thicknesses were investigated to determine their effect on the photovoltaic parameters of the cell. The overall efficiency of the best cells was approximately 5.3% under standard air mass 1.5 global (AM 1.5 G) solar conditions. Furthermore, the DSSCs showed an efficiency of approximately 3.15% due to the all Ti-mesh type electrodes even after illumination from the back side.
Nanotechnology 05/2012; 23(22):225602. · 3.98 Impact Factor
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ABSTRACT: This paper presents comprehensive results of the eco-friendly, large scale fabrication of nearly spherical Ho3+-doped Y2O3 submicron particles, synthesized using the urea homogeneous precipitation method. The dependence of the photoluminescence emission on the doping concentration was examined to determine the optimum Ho3+ concentration in the samples. X-ray diffraction data of the Y2O3:Ho3+ particles revealed a cubic Y2O3 structure. Field emission scanning electron microscopy confirmed the formation of nearly spherical shape particles with a mean diameter of 200±50 nm. The luminescence emission intensity significantly increased with increasing calcination temperature due to the improved crystallinity of the synthesized particles. Strong visible green-yellowish emission due to 5F4; 5S2–5I8 Stokes transitions was observed under constant 450 nm excitation. Simple large scale fabrication along with the strong visible green-yellowish emission might give these particles wide area of applications.
Journal of Physics and Chemistry of Solids 01/2012; · 1.63 Impact Factor
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ABSTRACT: We fabricated Volmer-Weber type ZnO nanorods by using a hydrothermal method combing with an RF sputtering system. Volmer-Weber type ZnO seed nanocrystals were formed on Pt(111)/TiO2/SiO2/Si(100) substrates by using RF sputtering method and then the seeded substrates were soaked in an aqueous chemical solution, which was mixed with Zn(NO3)2 x 6H2O and NaOH. We found that ZnO nanorods were perpendicularly grown along the [002] direction by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. We also confirmed that fabricated ZnO nanorods were Volmer-Weber type by using an energy dispersive X-ray spectrometer (EDX) method.
Journal of Nanoscience and Nanotechnology 12/2009; 9(12):6993-7. · 1.56 Impact Factor
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ABSTRACT: Well-aligned ultralong ZnO nanorod arrays with a length of 10 microm have been synthesized on glass substrates using a preheating hydrothermal method. The diameter of the nanorods is in the range from 50 to 80 nm, and the aspect ratio and alignment can be simply controlled by varying the preheating time. Based on the evolution of aspect ratio with preheating time, a possible growth mechanism was proposed. X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that the nanostructures are well oriented with the c-axis perpendicular to the substrate. The photoluminescence (PL) spectrum of the as-grown ZnO nanostructure reveals a near-band-edge (NBE) emission peak and a yellow emission, and the origin of yellow emission was confirmed to be from the absorbed hydroxyl group. The ultralong nanorod arrays made in solution have a desirable diameter, length, density and orientation for ordered nanodevice applications.
Nanotechnology 05/2009; 20(15):155603. · 3.98 Impact Factor
