Fabrication And Optical Properties Of Barium Borate And Lithium Niobate Nanorods

In this thesis, we choose the barium borate (β-BaB2O4, so calledβ-BBO) and Lithium Niobate (LiNbO3, so called LN), both of which have excellent nonlinear optical properties, to investigate the structure and optical preoperties of one-dimesion nanomatirials. In our experiments,β-BBO and LN nanorods were synthesized by the cetyltrimethylammonium bromide (CTAB) assisted hydrothermal method. The as-prepared nanorods were studied by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectra (XPS). The luminescence properties of the products were investigated by photoluminescence (PL) spectroscopy. The main contents are as the following:1, we synthesized pureβ-BBO single crystal phase by the CTAB assisted hydrothermal method, which have uniform diameters of 10²0 nm and lengths of several micro-meter.β-BBO nanorods have no obvious absorption edge in the range of UV-Vis-NIR. The measured SHG intensity ofβ-BBO nanorods are about 1.2 times that of urea. The room temperature PL spectrum indicate that there is a strong emission bands at 382 nm under photon excitation of 250 nm.2, The transition metal ions of Cu²⁺,Pb²⁺ and the rare earth metal ions of Er³⁺,Ce³⁺/Ce⁴⁺ were doped inβ-BBO nanorods. The results indicate that the structure of theβ-BBO nanorods doped with metal ions was unchanged. The novel emission phenomena were associated to the interaction of the metal ions and the host. The PL of Cu²⁺,Pb²⁺ co-dopedβ-BBO nanorods indicated a strong emission bands at 382 nm. Compared withβ-BBO nanorods, the center of luminescence was not chaged. At the same time, the results suggest that Cu²⁺ have sensitive action to Pb²⁺ and the luminescence intensity of the doped nanorods are enhanced remarkably. Upon excitation with 400 nm light, the Er³⁺, Ce³⁺/Ce⁴⁺ dopedβ-BBO nanorods exhibit a strong green light emission. PL spectra indicate that the emission bands at 515 and 542 nm correspond to the 2H11/2 and 4S3/2→4I15/2 transitions of Er³⁺, respectively. Compared with Er³⁺ dopedβ-BBO nanorods, the PL intensities of Er³⁺, Ce³⁺/Ce⁴⁺ co-dopedβ-BBO nanorods were enhanced remarkably. Ce³⁺ sensitizes Er³⁺ and energy transfer from Ce³⁺→Er³⁺ was observed.3, LN nanorods with uniform diameters of about 20 nm and lengths of about 100 nm were synthesized by the CTAB assisted hydrothermal method. The synthesis factors such as Lithium source, the molar ratio of Lithium and Niobium, temperature and reaction time were discussed. PL spectrum of LN nanorods showed novel properties. The intensity and position of emission peak were chaged with different the laser excitation wavelengthes. A strong emission bands at 390 nm under photon excitation of 240 nm was observed.