scholarly journals Silica Sol-gel Coatings with Improved Light Transmittance and Stability

Author(s):  
Lenke Kócs ◽  
Emőke Albert ◽  
Borbála Tegze ◽  
Márta Kabai-Faix ◽  
Csaba Major ◽  
...  

Silica sol-gel coatings on different substrate materials and their use as model systems have been studied. Mesoporous silica coatings with thicknesses of 85 - 135 nm and porosity of 18 ˗ 37% were prepared by dip-coating on polycarbonate and glass substrates. In order to eliminate the shrinkage of the porous structure acid or base vapour treatment was applied. Thickness and refractive index of the coatings were determined by analysing the transmittance spectra of the samples. Ellipsometric porosimetry measurements were carried out to determine the porosity, pore radius distribution, thickness and refractive index. The thickness of the samples was further confirmed by scanning electron microscopy. The adsorption capacity of the porous coatings was also studied by dye impregnation tests. The temporal stability of the samples was investigated by UV-Vis spectrometry and it was found that the advantageous optical properties (Tmax = 98 – 99%) of the samples remained constant even after a 1 year storage period.

2014 ◽  
Vol 26 (7) ◽  
pp. 72005
Author(s):  
张日东 Zhang Ridong ◽  
严鸿维 Yan Hongwei ◽  
吕海兵 Lü Haibing ◽  
张尽力 Zhang Jinli ◽  
晏良宏 Yan Lianghong ◽  
...  

2014 ◽  
Vol 597 ◽  
pp. 165-169
Author(s):  
Jie Hong Lei ◽  
Ri Dong Zhang

The porous sol-gel silica thin films were prepared on silicon substrate by the dip coating process. The surface roughness and microstructure of the film was measured by optical microscopy and AFM .Coating thickness and refractive index were measured by ellipsometry method. Influence of withdrawal speed and concentration of colloid was investigated for the thickness of silica. The relation of the thickness and withdrawal speed was fitted by the linear and power functions, and the results were analyzed and compared. It was found that the films with the same thickness prepared by different concentrations of colloid have different refractive indexes. The experimental results indicated that the thickness and refractive index of the film can be controlled by changing the withdrawal speed and colloid concentration.


2008 ◽  
Vol 8 (8) ◽  
pp. 3868-3876
Author(s):  
Sucheta De ◽  
Samar Kumar Medda ◽  
Goutam De

Au-plasmon tuning has been accomplished by controlling the refractive index (n) of the embedding film matrix. The refractive index of the film matrices were controlled by changing the molar ratios of low (SiO2) and high index (ZrO2) components following sol–gel reactions. Thus, Au nanoparticles doped films were prepared from SiO2-ZrO2 inorganic–organic hybrid sols of variable molar ratios containing HAuCl4 following the dip-coating method. The film samples deposited on glass substrates were obtained after drying, UV-treatment, and subsequent heat-treatment at 500 °C in air. The nominal mol ratios of SiO2:ZrO2 were 1:0, 1:1, 1:2.3, and 1:4. 3 equivalent mol% Au–97% total oxide (SiO2 + ZrO2) was maintained in the final heat-treated films. FTIR studies confirmed good homogeneity of Si-Zr network in the Zr-containing films. The UV-treatment has been introduced to facilitate the decomposition of HAuCl4 in the hybrid matrix prior to the heat-treatment step. The main Au-plasmon peak, in the case of a SiO2 host (SiO2:ZrO2 = 1:0, n = 1.410), observed at about 546 nm, gradually red-shifted to 592 nm upon increasing the ZrO2 content (SiO2:ZrO2 = 1:4, n = 1.847). Transmission electron microscopy of the final heat-treated (500 °C) films showed existence of plate-like (triangular and hexagonal) Au nanoparticles (25–50 nm) along with relatively smaller nanoparticles of about 10 nm in size. X-ray diffraction patterns reveal that the Au nanoparticles have a (111) orientation.


2013 ◽  
Vol 334-335 ◽  
pp. 290-293 ◽  
Author(s):  
N. Baydogan ◽  
T. Ozdurmusoglu ◽  
Huseyin Cimenoglu ◽  
A.B. Tugrul

Doped ZnO:Al thin films were deposited on glass substrates by the solgel dip technique. Optical parameters such as the refractive index and the extinction coefficient tend to change with increasing annealing temperature.


2015 ◽  
Vol 723 ◽  
pp. 528-531
Author(s):  
Jun Wang ◽  
Ling Yun Bai

TiO2 thin films were prepared on glass substrates by sol-gel method. The effect of withdraw speed on the thickness and optical properties of TiO2 thin films was investigated. The films were transparent in the visible wavelength. The thickness of the TiO2 films was increased from 90 nm for the withdraw speed of 1000 μm/s to 160 nm for the withdraw speed of 2000 μm/s. While, The refractive index of the TiO2 thin film decreased from 2.38 to 2.07. It may be due to the porosity of the film was increased. The optical band-gap of the films was around 3.45 eV.


1992 ◽  
Vol 271 ◽  
Author(s):  
Hiroshi Hirashima ◽  
Takao Kusaka

ABSTRUCTThe sol-gel method is one of the most appropriate technologies for the preparation of functional thin oxide coatings. However, few studies on the structure near the interface between sol-gel coatings and substrates have been reported. In this study, the structures of thin TiO2 gel coatings were investigated by XPS in order to elucidate the interaction between the coatings and the glass substrates. TiO2 gel coatings were prepared from Ti-alkoxide by hydrolysis and dip-coating on silica glass plates. Thickness and refractive index measurements were made by ellipsometry. Changes in Ols spectra for the coatings were observed at locations near the interface. Dynamic microhardness measurements for the coatings and the coated glasses were made. These results suggest the formation of a Ti-O-Si bond at the interface.


2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Marek Nocuń ◽  
Sławomir Kwaśny

AbstractIn our investigation, V doped SiO2/TiO2 thin films were prepared on glass substrates by dip coating sol-gel technique. Chemical composition of the samples was studied by X-ray photoelectron spectroscopy (XPS). Transmittance of the samples was characterized using UV-VIS spectrophotometry. Subsequently band-gap energy (Eg) was estimated for these films. Powders obtained from sols were characterized by FTIR spectroscopy. It was found that vanadium decreases optical band gap of SSiO2/TiO2 films.


Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7452
Author(s):  
Muhammad A. Butt ◽  
Andrzej Kaźmierczak ◽  
Cuma Tyszkiewicz ◽  
Paweł Karasiński ◽  
Ryszard Piramidowicz

In this paper, a novel and cost-effective photonic platform based on silica–titania material is discussed. The silica–titania thin films were grown utilizing the sol–gel dip-coating method and characterized with the help of the prism-insertion technique. Afterwards, the mode sensitivity analysis of the silica–titania ridge waveguide is investigated via the finite element method. Silica–titania waveguide systems are highly attractive due to their ease of development, low fabrication cost, low propagation losses and operation in both visible and near-infrared wavelength ranges. Finally, a ring resonator (RR) sensor device was modelled for refractive index sensing applications, offering a sensitivity of 230 nm/RIU, a figure of merit (FOM) of 418.2 RIU−1, and Q-factor of 2247.5 at the improved geometric parameters. We believe that the abovementioned integrated photonics platform is highly suitable for high-performance and economically reasonable optical sensing devices.


2014 ◽  
Vol 9 (3) ◽  
pp. 155892501400900 ◽  
Author(s):  
Marzieh Parhizkar ◽  
Yan Zhao ◽  
Xunagi Wang ◽  
Tong Lin

Photochromic fabrics were prepared by a dip-coating method using a silica sol-gel solution containing photochromic dyes. The coated fabric showed a rapid photochromic response. Three methods; incorporating a UV stabilizer in the coating layer, hydrophobic treatment of the porous surface, and covering the coating layer with an additional silica layer; were used to improve the photostability and durability. All three treatments improved the photostability without noticeably changing the photochromic response/fading speeds. Most of the treatments reduced the washing and abrasion durability. The extra coating layer increased the fabric rigidity.


2014 ◽  
Vol 903 ◽  
pp. 73-77
Author(s):  
Peh Ly Tat ◽  
Karim bin Deraman ◽  
Rosli Hussin ◽  
Wan Nurulhuda Wan Shamsuri ◽  
Zuhairi Ibrahim

ZnO thin films were deposited on the glass substrates via the sol-gel dip coating method. The films were annealed at various temperatures ranging from 350 °C to 550 °C. X-ray diffraction (XRD), and atomic force microscopy (AFM) were used to investigate the effect of annealing temperature on the structural and morphology properties of the films. The as grown films exhibited amorphous pattern while annealed films were polycrystalline structure with (002) preferential growth along c-axis orientation. The AFM micrographs revealed that the RMS roughness of the films increased as the annealing temperature increased. The grain size was ranging from 32.1 nm to 176.0 nm as the annealing temperature increased from 350 °C to 450 °C and decreased to 56.1 nm for 550 °C.


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