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Er3+/Yb3+ co-doped TiO2 nanocrystals were prepared by Sol-gel method in which titanium tetrachloride was adopted as the precursor. The structure, particle size, and optical properties of samples were characterized by X-ray diffraction(XRD), Field emission-Scanning Electron Microscopy(FE-SEM) and photoluminescence(PL) spectra. Er3+ concentration was fixed at 1.0mol%, and Yb3+ concentration was changed from 3 to 10mol%. Intense upconversion luminescence was observed when the samples were excited by 980nm laser. The dependence of upconversion luminescence on Yb3+ concentration was presented. The results show that the upconversion luminescence increases with the Yb3+ concentration and gets its peak at 5%. The ratio of red emission to green emission(R/G) was strikingly enhanced with the increase of Yb3+ concentration. Under the excitation of 980nm, the green emission in the range of 520-570nm (2H11/2, 4S3/2→4I15/2) and the red emission in the range of 640~690nm (4F9/2 →4I15/2) are both due to two photons process. The possible upconversion mechanism was discussed.

Noble metal nanoparticles have been a source of immense interest due to their novel properties and the uniqueness in properties due to high aspect ratio and quantum size effect resulting from their reduced size. In this paper, silver nanowires with an uniform diameter of 50nm were simply and successfully synthesized by solvothermal method using ethylene glycol as reducer in the presence of anodic alumina oxide (AAO) template. The experiment process is repeatable and the condition is moderate. The results of the field emission scanning electron microscope (FE-SEM) and the transmission electron microscope (TEM) show that there are more Ag nanowires with high aspect ratio produced on the surface of AAO and they are formed by many short nanowires connecting with each other from beginning to end. X-ray diffraction (XRD) and High-resolution transmission electron microscope (HRTEM) reveal that the prepared product is made of pure silver with face centered cubic structure. The optical properties were characterized by UV–Vis spectroscopy. The results reveal that Ag nanowires have a strong absorption band at about 378nm and 715nm which can be attributed to the transverse surface plasmon response(SPR) and the longitudinal surface plasmon response of the long silver nanowires.

A novel deposition way of nickel film for crystallization amorphous silicon film is introduced. Electroless nickel planting is a convenient and inexpensive way to deposit nickel without using the electric field or any large facility. A 200 nm nickel film is deposited on the glass substrates and then a 300nm a-Si film is deposited on the nickel film with a horizontal electric field assisted to enhance amorphous silicon crystallization. The bi-layer film is annealed at 500°C for several hours in the nitrogen atmosphere. The crystallized Si thin films were characterized by Raman spectroscopy, Field emission scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The Raman demonstrates that the a-Si has been crystallized. Furthermore the FE-SEM shows the lateral crystalline morphology, the length of grain is up to 5µm and the EDS reveals the nickel distribution in the MILC and MIC area.