Effective optical properties of highly ordered mesoporous thin films
Effective optical properties of highly ordered mesoporous thin films
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DOI：
10.1016/j.tsf.2009.08.048
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发表时间：
2010-02-01
期刊：
影响因子：
2.1
通讯作者：
Pilon, Laurent
中科院分区：
文献类型：
--
作者：
Hutchinson, Neal J.;Coquil, Thomas;Pilon, Laurent
本文扩展了我们以前的数值研究预测高度有序的介孔薄膜的光学性质从二维（2D）纳米结构的圆柱形孔的三维（3D）结构的球形孔。考虑了简单的、面心的和体心的球形孔的立方晶格和圆柱形孔的六方晶格，沿着具有各种孔径和孔隙率。通过求解三维麦克斯韦方程组，对垂直入射到介孔薄膜上的横向电和横向磁极化波的透射率和反射率进行了数值计算。薄膜的有效光学性质由逆方法确定。三维立方介孔薄膜的反射率被发现是独立的偏振，孔径，和膜的形态，只依赖于膜的厚度和孔隙率。相比之下，具有圆柱形孔的二维六方介孔膜的反射率取决于孔的形状和偏振。具有圆柱孔的二维六方介孔膜的非偏振反射率与具有相同孔隙率和厚度的三维立方介孔膜的非偏振反射率相同。3D薄膜的有效折射率和吸收率分别与3D Maxwell-Garnett和非对称Bruggeman有效介质近似的预测结果吻合良好。(C)2009爱思唯尔有限公司版权所有。
This paper expands our previous numerical studies predicting the optical Properties of highly ordered mesoporous thin films from two-dimensional (2D) nanostructures with cylindrical pores to three-dimensional (3D) structures with spherical pores. Simple, face centered, and body centered cubic lattices of spherical pores and hexagonal lattice of cylindrical Pores were considered along with various pore diameters and porosities. The transmittance and reflectance were numerically computed by solving 3D Maxwell's equations for transverse electric and transverse magnetic polarized waves normally incident on the mesoporous thin films. The effective optical properties of the films were determined by an inverse method. Reflectance of 3D cubic mesoporous thin films was found to be independent of polarization, pore diameter, and film morphology and depended only on film thickness and porosity. By contrast, reflectance of 2D hexagonal mesoporous films with cylindrical pores depended on pore shape and polarization. The unpolarized reflectance of 2D hexagonal mesoporous films with cylindrical pores was identical to that of 3D cubic mesoporous films with the same porosity and thickness. The effective refractive and absorption indices of 3D films show good agreement with predictions by the 3D Maxwell-Garnett and nonsymmetric Bruggeman effective medium approximations, respectively. (C) 2009 Elsevier B.V. All rights reserved.