含碳纳米颗粒凝胶玻璃的制备及其量子尺寸效应

以磷酸三乙酯、硝酸铝和正硅酸乙酯为原料,通过它们的不完全水解制备了含有有机基团的xAl₂O₃-xP₂O₅-100SiO₂(x=0.25—3)凝胶.在空气中在400℃或450℃或在氮气中从300到700℃对凝胶进行热处理,使凝胶中的有机基团炭化,从而得到含有碳纳米颗粒的xAl₂O₃-xP₂O₅-100SiO₂(x=0.25—2)凝胶玻璃.利用吸收光谱和TEM对含有碳纳米颗粒的凝胶玻璃进行了表征,结果发现随着碳纳米颗粒尺寸的减小吸收边向高能边移动,这种现象是由碳纳米颗粒中电子和空穴的量子限制效应引起的.电子衍射表明凝胶玻璃中的纳米碳为非晶碳. 关键词： 溶胶凝胶法 碳 纳米颗粒

SYNTHESIS AND QUANTUM SIZE EFFECT OF CARBON NANOPARTICLES DOPED IN GEL-GLASSES

C-nanoparticles with a diameter smaller than 60 nm in xAl2O3xP2O5-100SiO2(x=0.25—2) gel-glasses have been prepared by sol-gel process. The gels synthesized through partial hydrolysis of PO(OC2H5)3,Al(NO3)3·9H2O and Si(OC2H5)4 were heated at 400℃ or 450℃ in air atmosphere or from 300 to 700℃ in N2 atmosphere, in which —OC\-2H\-5 were carbonized to form nanosized C particles. These C-nanoparticles-doped gel-glasses were characterized by optical absorption and TEM.The optical absorption edge shifts to the higher-energy side as the size of the C particle decreases. This phenomenon is interpreted in terms of a quantum confinement effect of electron and hole in the C-nanoparticles. The C-nanoparticles structures were found to be amorphous carbon in the gel-glasses by electron diffraction pattern.