scholarly journals Solvent Effect to the Uniformity of Surfactant-Free Salmon-DNA Thin Films

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1606
Author(s):  
Jake Richter ◽  
Moses Nnaji ◽  
Heungman Park
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Solvent Effect ◽  
Spin Coating ◽  
Physical Parameters ◽  
High Uniformity ◽  
Modified Dna ◽  
Coating Methods ◽  
Dna Solutions ◽  
Focused Beam

Fabrication of surfactant-modified DNA thin films with high uniformity, specifically DNA–CTMA, has been well considered via drop-casting and spin-coating techniques. However, the fabrication of thin films with pure DNA has not been sufficiently studied. We characterize the uniformity of thin films from aqueous salmon DNA solutions mixed with ethanol, methanol, isopropanol, and acetone. Measurements of thickness and macroscopic uniformity are made via a focused-beam ellipsometer. We discuss important parameters for optimum uniformity and note what the effects of solvent modifications are. We find that methanol- and ethanol-added solutions provide optimal fabrication methods, which more consistently produce high degrees of uniformity with film thickness ranging from 20 to 200 nm adjusted by DNA concentration and the physical parameters of spin-coating methods.

Photoluminescence and Electroluminescence Properties of (Ca,Sr)TiO3:Er

2016 ◽  
Vol 698 ◽  
pp. 60-65 ◽  
Author(s):  
Tôru Kyômen ◽  
Miyu Seki ◽  
Minoru Hanaya ◽  
Hiroshi Takashima
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Band Gap ◽  
Solid State Reaction ◽  
Spin Coating ◽  
Sol Gel ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Powder Samples ◽  
Coating Methods

Powder samples of (Ca,Sr)TiO3:Er were prepared by a solid-state reaction method. Photoluminescence due to f-f transitions of Er3+ was not induced by band-gap excitation of (Ca,Sr)TiO3 but by f-f transitions of Er3+. An electroluminescent device in which thin films of Ca0.6Sr0.4TiO3:Er and SnO2:Sb are stacked alternately was prepared by sol-gel and spin-coating methods. Very weak electroluminescence due to f-f transition of Er3+ was observed in the device.

scholarly journals Fabrication by Spin-Coating and Optical Characterization of Poly(styrene-co-acrylonitrile) Thin Films

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1015
Author(s):  
Elizabeth Hedl ◽  
Ivana Fabijanić ◽  
Iva Šrut Rakić ◽  
Ivan Vadla ◽  
Jordi Sancho-Parramon
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Film Thickness ◽  
Spin Coating ◽  
Visible Range ◽  
Force Microscopy ◽  
Atomic Force ◽  
Linear Behavior ◽  
Concentrated Solution ◽  
Dependent Viscosity

The optical characteristics of poly(styrene-co-acrylonitrile) thin films obtained by spin-coating of polymer blend in tetrahydrofuran were investigated by spectroscopic ellipsometry, spectrophotometry, and atomic force microscopy. Film thickness can be broadly varied by changing the polymer concentration.The film thickness dependence on PSAN concentration shows a non-linear behavior that can be explained by a concentration-dependent viscosity. According to previously proposed models, prepared solutions are close to the concentrated solution regime. Films show a broad transparency range and refractive index independent of film thickness. The refractive index values range from 1.55 to 1.6 in the visible range. Thermal treatment revealed good stability of the films up to 220 °C and a progressive deterioration for larger temperatures, with evident damage at 300 °C. UV-induced photodegradation was observed and results showed a progressive decrease of transmittance in the range between 200 and 300 nm but PSAN thin films show no changes when exposed to light from a solar illuminator. These investigations indicate that PSAN is an excellent candidate for thin film polymer-based optical uses like interference coatings or encapsulation of solar cells.

scholarly journals Fractal-Stereometric Correlation of Nanoscale Spatial Patterns of GdMnO3 Thin Films Deposited by Spin Coating

2021 ◽  
Vol 11 (9) ◽  
pp. 3886
Author(s):  
Yonny Romaguera-Barcelay ◽  
Ştefan Ţălu ◽  
Robert Saraiva Matos ◽  
Rosane Maria Pessoa Betânio Oliveira ◽  
Joaquim Agostinho Moreira ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Spatial Patterns ◽  
Spin Coating ◽  
Lower Surface ◽  
Physical Parameters ◽  
Si Substrates ◽  
Topographic Roughness ◽  
Atomic Force ◽  
Fractal Parameters

Multiferroic systems are of great interest for technological applications. To improve the fabrication of thin films, stereometric and fractal analysis of surface morphology have been extensively performed to understand the influence of physical parameters on the quality of spatial patterns. In this work, GaMnO3 was synthesized and thin films were deposited on Pt(111)/TiO2/SiO2/Si substrates using a spin coating apparatus to study the correlation between their stereometric and fractal parameters. All films were studied by X-ray diffraction (XRD), where the structure and microstructure of the film sintered at 850 °C was investigated by Rietveld refinement. Topographic maps of the films were obtained using an atomic force microscope (AFM) in tapping mode. The results show that the film sintered at 850 °C exhibited a clear formation of a GdMnO3 orthorhombic structure with crystallite size of ~14 nm and a microstrain higher than other values reported in the literature. Its surface morphology presented a rougher topography, which was confirmed by the height parameters. Topographic differences due to different asymmetries and shapes of the height distributions between the films were observed. Specific stereometric parameters also showed differences in the morphology and microtexture of the films. Qualitative rendering obtained by commercial image processing software revealed substantial differences between the microtextures of the films. Fractal and advanced fractal parameters showed that the film sintered at 850 °C had greater spatial complexity, which was due to their higher topographic roughness, lower surface percolation and greater topographic uniformity, being dominated by low dominant special frequencies. Our combination of stereometric and fractal measurements can be useful to improve the fabrication process by optimizing spatial patterns as a function of the sintering temperature of the film.

Electroluminescence of a Multilayer in which Thin Films of NaNbO3:Pr Phosphor and SnO2:Sb Transparent Conductor Are Alternately Stacked

2015 ◽  
Vol 643 ◽  
pp. 33-37 ◽  
Author(s):  
Tôru Kyômen ◽  
Sayaka Hasuko ◽  
Minoru Hanaya ◽  
Hiroshi Takashima
Keyword(s):  
Thin Films ◽  
Spin Coating ◽  
Sol Gel ◽  
Transparent Conductor ◽  
Electroluminescent Device ◽  
Coating Methods

Oxide inorganic electroluminescent device in which thin films of Pr-doped NaNbO3 phosphor and Sb-doped SnO2 transparent conductor are alternately stacked was prepared by sol-gel and spin-coating methods. Red electroluminescence was observed due to f-f transitions of Pr3+ ions by applying 5-kHz ac voltages to the device. The luminance was 1.0 cd m−2 at 25 V ac and5.0 cd m−2 at 34 V ac.

Influence of Film Thickness and Annealing Temperature on Optical Properties of Nanostructured-TiO2 Thin Films Prepared by Sol–Gel Spin Coating Technique

2016 ◽  
Vol 16 (02) ◽  
pp. 1650028 ◽  
Author(s):  
A. A. A. Darwish ◽  
F. S. Abu-Samaha ◽  
Z. Mohamed ◽  
M. M. El-Nahass
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Spin Coating ◽  
Optical Constants ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Spin Coating Technique ◽  
Tio2 Thin Films ◽  
Coating Technique ◽  
Quartz Substrates

TiO2 powder was found to be polycrystalline with rutile system. TiO2 films were deposited on quartz substrates by a sol–gel spin coating technique. X-ray diffraction and transmission electron microscope results have confirmed that the TiO2 films have nanostructure nature. It is found the crystallite size increased with annealing temperature. The optical constants of nanostructured TiO2 films were found to be independent of film thickness in the range from 100[Formula: see text]nm to 500[Formula: see text]nm. It is found that the optical constants and the dielectric constant of the thin films were all affected by annealing temperature. The existing allowed optical transitions in the as-deposited and annealed films were found to be direct and indirect transitions. Finally, the bandgaps of the as-deposited film were found to decrease with the annealing temperature.

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