Fabrication of large-area and high-quality colloidal crystal films on nanocrystalline porous substrates by a room temperature floating self-assembly method

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• 作者：Ai Jun Wang^a ; ^b ; Sheng-Li Chen^a ; ^{slchen@cup.edu.cn} ; Peng Dong^a ; ^{p.dong@china.com} ; Chun Tian Hu^a ; Lei Sang^a
• 关键词：Colloidal crystal ; Porous nanocrystalline substrate ; Floating self-assembly ; Air− ; liquid interface
• 刊名：Thin Solid Films
• 出版年：2011
• 出版时间：3 January 2011
• 年：2011
• 卷：519
• 期：6
• 页码：1798-1802
• 全文大小：989 K

文摘

When colloidal crystal films are deposited onto nanocrystalline porous substrates by the commonly used colloidal crystallization method of vertical deposition self-assembly, the colloidal crystal tends to be poorly adhered to the porous film. Herein, we present a fabrication of large-area, three-dimensional (3D) colloidal crystal thin films on nanocrystalline porous substrates by a room temperature floating self-assembly method that has recently been developed for colloidal crystal deposition. Firstly, colloidal suspensions were prepared by dispersing monodisperse colloidal microspheres at high volume fraction in a mixture of ethanol and water. At room temperature, these suspensions were spread onto nanocrystalline porous TiO₂ films. The colloidal particles assembled into 3D ordered structures at the air−liquid interface of the suspensions as a result of rapid evaporation of the solvents. After the solvents (water and ethanol) had evaporated completely, the colloidal crystals were directly deposited on the nanocrystalline porous TiO₂ films. Scanning electron microscopy images and normal-incidence transmission spectra of the samples showed that the colloidal crystal films deposited on the nanocrystalline porous TiO₂ substrates by this method had very high crystalline quality. In addition, the effect of the degree of surface roughness of the nanocrystalline porous substrate on the crystalline quality of the colloidal crystals has been studied.