کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1495281 992932 2011 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Selective IR absorption in molecular nanofilms
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Selective IR absorption in molecular nanofilms
چکیده انگلیسی

We have formulated a microscopic theory of optical properties of ultrathin molecular films (nanofilms), i.e. quasi 2D systems parallel to XY planes bounded by two surfaces. Exposure of nanofilms to the external electromagnetic fields has result in creation of excitons – but different than bulk ones. Harmonic exciton states were calculated using the method of two-time, retarded, temperature dependent Green’s functions. It has been shown that two types of optical excitations can occur: bulk and surface exciton states. Exciton energy dispersion law shows discrete behavior with non-zero values. Analysis of the dielectric properties of these crystalline systems for low exciton concentration shows that the permittivity strongly depends on boundary parameters and the thickness of the film. In addition, permittivity shows very narrow and discrete dependence of external electromagnetic field frequency, which is a consequence of both resonance and quantum size effects. Influences of boundary conditions on optical characteristics (through analyses of dynamical absorption coefficient) of these nanostructures were specially and in details explored.


► Microscopic theory of optical properties of ultrathin molecular films is formulated.
► Harmonic exciton states were calculated using the Green’s functions method.
► Absorption index shows discrete peaks at certain frequencies of external EMF.
► All peaks are in infrared region.
► Strongly selective absorption appears.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Optical Materials - Volume 33, Issue 11, September 2011, Pages 1578–1584
نویسندگان
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