Second Order Nonlinear Optical Films by Alternating Polyelectrolyte Deposition on Hydrophilic and Hydrophobic Substrates

1999 ◽  
Vol 598 ◽  
Author(s):  
M. Joseph Roberts ◽  
Warren N. Herman
Keyword(s):  
Film Thickness ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Linear Increase ◽  
Second Order ◽  
Force Microscopy ◽  
Atomic Force ◽  
Layer Deposition ◽  
Optical Films ◽  
Nonlinear Optical Polymers

ABSTRACTAlternating polyelectrolyte deposition (APD) is a room temperature process that can be used to produce noncentrosymmetric ordered films of nonlinear optical polymers (NLOP). In this study, second-order NLOP APD films of a stilbazolium-substituted polyepichlorohydrin, poly (diallyldimethylammonium chloride), and polyacrylic acid were prepared by alternately dipping a substrate into aqueous solutions of each polymer. Evidence for uniform layer to layer deposition includes a linear increase of UV-Visible absorbance, thickness measurements, and quadratic increase of second harmonic generated light intensity as a function of film thickness. Films have been uniformly deposited up to 0.1 micrometer thick. The surface morphology, roughness, and film thickness have been characterized by Tapping Mode Atomic Force Microscopy (TM AFM ). Work is in progress to deposit thicker films of the same quality and to improve NLO figures of merit.

Second-Order Nonlinear Optical Polymers With Different Chromophore Arrangements

1993 ◽  
Vol 328 ◽  
Author(s):  
Bo Wu ◽  
Chengzeng Xu ◽  
Larry R. Dalton ◽  
Srinath Kalluri ◽  
Yongqiang Shi ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Main Chain ◽  
Second Harmonic ◽  
Polymeric Materials ◽  
Second Order ◽  
Side Chain ◽  
Optical Polymers ◽  
Nonlinear Optical Polymers ◽  
Main Chain Polymers

ABSTRACTSecond-order nonlinear optical polymers can be divided into four groups regarding arrangements of chromophore dipoles in polymer backbones, namely, side-chain polymers, random, head-to-tail, and head-to-head Main-chain polymers. A variety of polymers with the aforementioned configurations have been designed and synthesized from functionalized amino-nitro azobenzene chromophores. Poling processes of these polymeric materials have been investigated by in-situ poling and second-harmonic generation detection.

Effect of Water Temperature, pH Value, and Film Thickness on the Wettability Behaviour of Copper Surfaces Coated with Copper Using EB-PVD Technique

2019 ◽  
Vol 60 ◽  
pp. 124-141 ◽  
Author(s):  
Naser Ali ◽  
Joao Amaral Teixeira ◽  
Abdulmajid Addali
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Film Thickness ◽  
Water Temperature ◽  
Ph Value ◽  
Surface Wettability ◽  
Copper Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Static Contact

This research investigates the effect of surface roughness, water temperature, and pH value on the wettability behaviour of copper surfaces. An electron beam physical vapour deposition technique was used to fabricate 25, 50, and 75 nm thin films of copper on the surface of copper substrates. Surface topographical analysis, of the uncoated and coated samples, was performed using an atomic force microscopy device to observe the changes in surface microstructure. A goniometer device was then employed to examine the surface wettability of the samples by obtaining the static contact angle between the liquid and the attached surface using the sessile drops technique. Waters of pH 4, 7, and 9 were employed as the contact angle testing fluids at a set of fixed temperatures that ranged from 20°C to 60°C. It was found that increasing the deposited film thickness reduces the surface roughness of the as-prepared copper surfaces and thus causing the surface wettability to diverge from its initial hydrophobic nature towards the hydrophilic behaviour region. A similar divergence behaviour was seen with the rise in temperature of water of pH 4, and 9. In contrast, the water of pH 7, when tested on the uncoated surface, ceased to reach a contact angle below 90o. It is believed that the observed changes in surface wettability behaviour is directly linked to the liquid temperature, pH value, surface roughness, along with the Hofmeister effect between the water and the surface in contact.

scholarly journals A Molecular Architectural Approach to Second-Order Nonlinear Optical Materials

1995 ◽  
Vol 392 ◽  
Author(s):  
Xiaoguang Yang ◽  
Duncan McBranch ◽  
Basil Swanson ◽  
Dequan Li
Keyword(s):  
Nonlinear Optical ◽  
Second Harmonic ◽  
Fused Silica ◽  
Second Order ◽  
Nonlinear Susceptibility ◽  
Design And Synthesis ◽  
Fundamental Wavelength ◽  
Assembled Monolayers ◽  
Methylene Groups ◽  
Nlo Chromophores

AbstractThe design and synthesis of a family of calix[4]arene-based nonlinear optical (NLO) chromophores are discussed. The calixarene chromophores are macrocyclic compounds consisting of four simple D-π-A units bridged by methylene groups. These molecules were synthesized such that four D-π-A units of the calix[4]arene were aligned along the same direction with the calixarene in a cone conformation. These nonlinear optical super-chromophores were subsequently fabricated into covalently bound self-assembled monolayers on the surfaces of fused silica and silicon. Spectroscopic second harmonic generation (SHG) measurements were carried out to determine the absolute value of the dominant element of the second-order nonlinear susceptibility, d33, and the average molecular alignment, ψ. We find a value of d33 = 60 pm/V at a fundamental wavelength of 890 nm, and ψ˜ 36° with respect to the surface normal.

Zinc Oxide Thin Film Morphology as Function of Substrate Position During Sputtering Process

2021 ◽  
Vol 900 ◽  
pp. 103-111
Author(s):  
Christelle Habis ◽  
Jean Zaraket ◽  
Michel Aillerie
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Low Cost ◽  
Linear Increase ◽  
Oxide Thin Film ◽  
Central Position ◽  
Zinc Oxide Thin Film ◽  
Force Microscopy ◽  
Atomic Force ◽  
Great Transparency

Transparent conductive oxides are materials combining great transparency with high conductivity. In photovoltaic applications, they are developed under thin layer for the realization of upper electrodes of solar cells. Among transparent oxide materials, Zinc Oxide (ZnO) presents unique properties, starting with its first qualities to be abundant, low-cost and non-toxic oxide. Zinc Oxide thin film was deposited on rectangular glass substrate by magnetron sputtering. After an overview of the properties expected for good transparent conductive materials, the effect of distance from the center of the cell on the morphology of the film was investigated by Atomic Force Microscopy (AFM). The scanning was done on different area of the sample as function of the distance from the central position of the direct sputtering jet. As far as the distance increased, it has been noticed a quasi-linear increase in thickness of the ZnO deposited film and a change in the grain shape from spherical to pyramidal with an increase in the size of the particles. Controlling the sputtering distance allows the control of texture, thus of the Haze factor, the photo-generation of excitons, as well the optical transmission of the TCO layer and finally an improvement in the efficiency of the so-built photovoltaic cells.

scholarly journals Development of Second-Order Nonlinear Optical Polymers without Visible Absorption

2003 ◽  
Vol 60 (12) ◽  
pp. 682-692 ◽  
Author(s):  
Tatsumi KIMURA ◽  
Takashi FUKUDA ◽  
Hiro MATSUDA ◽  
Masao KATO ◽  
Hachiro NAKANISHI
Keyword(s):  
Nonlinear Optical ◽  
Second Order ◽  
Optical Polymers ◽  
Visible Absorption ◽  
Nonlinear Optical Polymers

Structural and Morphological Characterization of Ultrathin Films of an Asymmetric Polydiacetylene

1996 ◽  
Vol 440 ◽  
Author(s):  
H. C. Wang ◽  
D. W. Cheong ◽  
J. Kumar ◽  
C. Sung ◽  
S. K. Tripathy
Keyword(s):  
Second Harmonic ◽  
Morphological Characterization ◽  
Lb Films ◽  
Force Microscopy ◽  
Langmuir Blodgett ◽  
Glass Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Air Water Interface

AbstractA soluble, asymmetrically substituted polydiacetylene, poly(BPOD), has been reported to form stable monolayers at the air-water interface by the Langmuir-Blodgett (LB) technique [2]. Preformed polydiacetylene has been deposited onto hydrophobic substrates as multilayers to form second order nonlinear optical thin films. Second harmonic generation was found to increase with the number of layers. From previous atomic force microscopy (AFM) studies backbone orientation along the dipping direction with an interchain spacing of about 5 A° was indicated [2].The film morphology and preferential molecular orientation of these LB films are further investigated by transmission electron microscopy (TEM). A specifically tailored sample preparation method for the ultrathin LB films was used. Multilayer films were deposited on hydrophobic collodion covered glass substrates for this purpose. Electron diffraction was employed to study the crystalline organization of mono and multilayers of LB films as well as cast films.

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