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Antireflection Coatings (antireflection + coating)
Selected AbstractsPorous Polymer Films with Gradient-Refractive-Index Structure for Broadband and Omnidirectional Antireflection CoatingsADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Xiao Li Abstract Porous polymer films that can be employed for broadband and omnidirectional antireflection coatings are successfully shown. These films form a gradient-refractive-index structure and are achieved by spin-coating the solution of a polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA)/PMMA blend onto an octadecyltrichlorosilane (OTS)-modified glass substrate. Thus, a gradient distribution of PMMA domains in the vertical direction of the entire microphase-separated film is obtained. After those PMMA domains are removed, a PS porous structure with an excellent gradient porosity ratio in the vertical direction of the film is formed. Glass substrates coated with such porous polymer film exhibit both broadband and omnidirectional antireflection properties because the refractive index increases gradually from the top to the bottom of the film. An excellent transmittance of >97% for both visible and near-infrared (NIR) light is achieved in these gradient-refractive-index structures. When the incident angle is increased, the total transmittance for three different incident angles is improved dramatically. Meanwhile, the film possesses a color reproduction character in the visible light range. [source] Broad-band and Omnidirectional Antireflection Coatings Based on Semiconductor NanorodsADVANCED MATERIALS, Issue 9 2009Silke L. Diedenhofen A broad-band and omnidirectional antireflection coating consisting of semiconductor nanowires is fabricated. The reflection is reduced due to a graded refractive index, which is achieved by a certain nanorod-length distribution of cylindrical and conically shaped rods. An increased transmission and, accordingly, a reduced reflection are demonstrated for the visible and near-infrared parts of the spectrum. [source] Erasable Nanoporous Antireflection Coatings Based on the Reconstruction Effect of Layered Double Hydroxides,ANGEWANDTE CHEMIE, Issue 12 2010Jingbin Han Auf Wunsch Entspiegelung: Die Entspiegelungseigenschaften eines nanoporösen Überzugs, der aus Nanopartikel aus einem schichtförmigen Doppelhydroxid und Polyanionen aufgebaut wurde, ändern sich reversibel beim Schalten zwischen porösem und nichtporösem Zustand durch Kalzinieren und Rehydratisieren. [source] Flexible nanocrystalline-titania/polyimide hybrids with high refractive index and excellent thermal dimensional stabilityJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2010Guey-Sheng Liou Abstract In this study, a novel synthetic route was developed to prepare polyimide,nanocrystalline,titania hybrid optical films with a relatively high titania content (up to 50 wt %) and thickness (20,30 ,m) from soluble polyimides containing hydroxyl groups. Two series of newly soluble polyimides were synthesized from the hydroxy-substituted diamines with various commercial tetracarboxylic dianhydrides. The hydroxyl groups on the backbone of the polyimides could provide the organic,inorganic bonding and resulted in homogeneous hybrid solutions by controlling the mole ratio of titanium butoxide/hydroxyl group. AFM, SEM, TEM, and XRD results indicated the formation of well-dispersed nanocrystalline-titania. The flexible hybrid films could be successfully obtained and revealed relatively good surface planarity, thermal dimensional stability, tunable refractive index, and high optical transparency. A three-layer antireflection coating based on the hybrid films was prepared and showed a reflectance of less than 0.5% in the visible range indicated its potential optical applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1433,1440, 2010 [source] Investigation of graded index SiOxNy antireflection coating for silicon solar cell manufacturingPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2007M. Lipi Abstract An optimization of SiOxNy anti-reflective coatings with graded index layers for silicon solar cells based on the Bruggeman's effective medium approximation is presented. For simulation of reflectance and absorption of graded layer, the experimental optical data of silicon nitride SiNx:H and oxynitride SiOxNy obtained by Low Frequency (440 kHz) Plasma Enhanced Chemical Vapour Deposition (LF-PECVD) were used. We have shown that the graded index oxynitride antireflection coating can reduce the effective reflectance to about 2.5% but the high absorption due to high extinction coefficient compensates this improvement and reduces the short circuit current (Jsc) of the solar cell. The improvement in the Jsc can be obtained for graded SiNxOy layer with smaller value of refractive index of SiNx (n = 2.2). In this case the graded SiOxNy layer is characterized by an abrupt concentration profile and can be considered as a double antireflection coating SiO2/SiNx. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] GaAs converters for high power densities of laser illuminationPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 4 2008E. Oliva Abstract Photovoltaic power converters can be used to generate electricity directly from laser light. In this paper we report the development of GaAs PV power converters with improved conversion efficiency at high power densities. The incorporation of a lateral conduction layer (LCL) on top of the window layer resulted in a considerable gain in efficiency at high illumination levels. Additional performance improvements were obtained by using a metal electrode grid design and antireflection coating optimised for monochromatic and inhomogeneous laser light. Maximum monochromatic (810,nm) optical-to-electrical conversion efficiency of 54·9% at 36·5,W/cm2 has been achieved. The characteristics of laser power converters with p/n and n/p polarity are discussed in this paper. Moreover, different materials and doping levels were applied in the LCL. The performance of these different device structures at high laser intensity is presented and discussed. It is shown that the lateral series resistance of the cell has a major impact on the overall device performance. Copyright © 2008 John Wiley & Sons, Ltd. [source] Porous Polymer Films with Gradient-Refractive-Index Structure for Broadband and Omnidirectional Antireflection CoatingsADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Xiao Li Abstract Porous polymer films that can be employed for broadband and omnidirectional antireflection coatings are successfully shown. These films form a gradient-refractive-index structure and are achieved by spin-coating the solution of a polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA)/PMMA blend onto an octadecyltrichlorosilane (OTS)-modified glass substrate. Thus, a gradient distribution of PMMA domains in the vertical direction of the entire microphase-separated film is obtained. After those PMMA domains are removed, a PS porous structure with an excellent gradient porosity ratio in the vertical direction of the film is formed. Glass substrates coated with such porous polymer film exhibit both broadband and omnidirectional antireflection properties because the refractive index increases gradually from the top to the bottom of the film. An excellent transmittance of >97% for both visible and near-infrared (NIR) light is achieved in these gradient-refractive-index structures. When the incident angle is increased, the total transmittance for three different incident angles is improved dramatically. Meanwhile, the film possesses a color reproduction character in the visible light range. [source] | ||||||||||