International School of Photonics, CUSAT, Kochi, India.
J Fluoresc. 2012 Nov;22(6):1563-9. doi: 10.1007/s10895-012-1096-3. Epub 2012 Jul 5.
TiO(2) colloidal nanoparticles and nanocrystals are prepared by hydrolysis of titanium isopropoxide employing a surfactant-free synthetic hydrothermal method. The synthesized samples are characterized by X-ray diffraction (XRD), HRTEM and FTIR. The XRD study confirms that the size of the colloidal nanoparticle is around 4 nm which the HRTEM analysis indicates the sizes of the colloidal nanoparticles are in the range of 2.5 nm. The fluorescence property of the TiO(2) colloidal nanoparticles studied by the emission spectrum confirms the presence of defect levels caused by the oxygen vacancies. We have observed new emission bands at 387 nm,421 nm, 485 nm, 530 nm and 574 nm wavelengths, first one (387 nm) being emission due to annihilation of excitons while remaining four could be arising from surface states. The emission spectrum of annealed nanocrystallites is also having these four band emissions. It is observed that the surface state emission basically consists of two categories of emission.
采用无表面活性剂的水热合成方法，通过钛异丙醇盐的水解制备 TiO(2)胶体纳米粒子和纳米晶体。通过 X 射线衍射（XRD）、高分辨率透射电子显微镜（HRTEM）和傅里叶变换红外光谱（FTIR）对合成的样品进行了表征。XRD 研究证实胶体纳米粒子的尺寸约为 4nm，HRTEM 分析表明胶体纳米粒子的尺寸在 2.5nm 范围内。通过发射光谱研究 TiO(2)胶体纳米粒子的荧光性质，证实了氧空位引起的缺陷能级的存在。我们观察到在 387nm、421nm、485nm、530nm 和 574nm 波长处出现新的发射带，第一个（387nm）是激子湮灭引起的发射，而其余四个可能是由表面态引起的。退火纳米晶的发射光谱也具有这四个带的发射。观察到表面态发射基本上由两类发射组成。
