Lu S G, Mak C L, Pang G K H, Wong K H, Cheah K W
Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
Nanotechnology. 2008 Jan 23;19(3):035702. doi: 10.1088/0957-4484/19/03/035702. Epub 2007 Dec 11.
Transparent PbZr(0.52)Ti(0.48)O(3) (PZT)-doped silica nanocomposites were fabricated via a modified sol-gel process. The nanocomposites were annealed at different temperatures between 740 and 800 °C in order to produce PZT crystallites with different particle sizes. X-ray diffraction analysis indicated that the embedded PZT nanoparticles were crystallized with a perovskite structure while the SiO(2) matrix was still in an amorphous state. Transmission electron microscopy confirmed that the PZT particles were of nanosize with perovskite structure and dispersed within the SiO(2) matrix. Photoluminescence spectra of the samples were measured between 10 and 290 K. The pure silica matrix showed an emission band at 3.20 eV and a weak emission band at 2.65 eV. They were noticeably suppressed in the PZT/SiO(2) nanocomposites. An additional emission band at ∼2.30 eV, due to transition within the PZT crystallites, was identified. This emission band showed a large blue-shift with decreasing PZT crystallite size and a substantially enhanced intensity as compared with that of bulk PZT ceramics. Our studies demonstrate the typical quantum size effect of ferroelectric-doped nanocomposites and the large influence of the silica matrix on the PL intensity of the embedded PZT particles.
通过改进的溶胶 - 凝胶法制备了透明的掺杂PbZr(0.52)Ti(0.48)O(3)（PZT）的二氧化硅纳米复合材料。为了制备具有不同粒径的PZT微晶，将纳米复合材料在740至800 °C之间的不同温度下进行退火。X射线衍射分析表明，嵌入的PZT纳米颗粒以钙钛矿结构结晶，而SiO(2)基体仍处于非晶态。透射电子显微镜证实，PZT颗粒为纳米尺寸，具有钙钛矿结构，并分散在SiO(2)基体内。在10至290 K之间测量了样品的光致发光光谱。纯二氧化硅基体在3.20 eV处有一个发射带，在2.65 eV处有一个弱发射带。它们在PZT/SiO(2)纳米复合材料中明显受到抑制。由于PZT微晶内的跃迁，在约2.30 eV处发现了一个额外的发射带。与块状PZT陶瓷相比，该发射带随着PZT微晶尺寸的减小呈现出较大的蓝移，并且强度大幅增强。我们的研究证明了铁电掺杂纳米复合材料的典型量子尺寸效应以及二氧化硅基体对嵌入的PZT颗粒的光致发光强度的重大影响。
