scholarly journals Silica-Copper Oxide Composite Thin Films as Solar Selective Coatings Prepared by Dipping Sol Gel

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
E. Barrera-Calva ◽  
J. Méndez-Vivar ◽  
M. Ortega-López ◽  
L. Huerta-Arcos ◽  
J. Morales-Corona ◽  
...  

Silica-copper oxide (silica-CuO) composite thin films were prepared by a dipping sol-gel route using ethanolic solutions comprised TEOS and a copper-propionate complex. Sols with different TEOS/Cu-propionate (Si/Cu) molar ratios were prepared and applied on stainless steel substrates using dipping process. During the annealing process, copper-propionate complexes developed into particulate polycrystalline CuO dispersed in a partially crystallized silica matrix, as indicated by the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. The gel thermal analysis revealed that the prepared material might be stable up to400°C. The silica-CuO/stainless steel system was characterized as a selective absorber surface and its solar selectivity parameters, absorptance (α), and emittance (ε) were evaluated from UV-NIR reflectance data. The solar parameters of such a system were mostly affected by the thickness and phase composition of theSiO2-CuO film. Interestingly, the best solar parameters (α= 0.92 andε= 0.2) were associated to the thinnest films, which comprised a CuO-Cu2Omixture immersed in the silica matrix, as indicated by XPS.

2007 ◽  
Vol 280-283 ◽  
pp. 795-800 ◽  
Author(s):  
Huogen Yu ◽  
Jia Guo Yu ◽  
Bei Cheng ◽  
C.H. Ao ◽  
S.C. Lee

TiO2 thin films were prepared on soda lime glass, fused quartz and stainless steel substrates by liquid phase deposition (LPD) method from a (NH4)2TiF6 aqueous solution upon the addition of boric acid (H3BO3), and then calcined at 500oC for 2 h. The prepared films were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It was found that the substrates obviously influenced the element composition and microstructure of TiO2 thin films. Except Ti, O and a small amount of F and N elements, which came from the precursor solution, some Si (or Fe) element in the thin films deposited on soda lime glass and quartz substrates (or on stainless steel substrate) was confirmed. The Si (or Fe) element in the thin films could be attributed to two sources. One was from the SiF6 2- ions (or FeF6 2- ions) formed by a reaction between the treatment solution and soda lime glass or quartz (or stainless steel) substrates. The other was attributed to the diffusion of Si (or Fe) from the surface of substrates into the TiO2 thin films after calcination at 500oC. The Si (or Fe) element in the TiO2 thin films could behave as a dopant and resulted in the formation of composite SiO2/TiO2 (or Fe2O3/TiO2) thin films on the substrates.


Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 478
Author(s):  
Wan Mohd Ebtisyam Mustaqim Mohd Daniyal ◽  
Yap Wing Fen ◽  
Silvan Saleviter ◽  
Narong Chanlek ◽  
Hideki Nakajima ◽  
...  

In this study, X-ray photoelectron spectroscopy (XPS) was used to study chitosan–graphene oxide (chitosan–GO) incorporated with 4-(2-pyridylazo)resorcinol (PAR) and cadmium sulfide quantum dot (CdS QD) composite thin films for the potential optical sensing of cobalt ions (Co2+). From the XPS results, it was confirmed that carbon, oxygen, and nitrogen elements existed on the PAR–chitosan–GO thin film, while for CdS QD–chitosan–GO, the existence of carbon, oxygen, cadmium, nitrogen, and sulfur were confirmed. Further deconvolution of each element using the Gaussian–Lorentzian curve fitting program revealed the sub-peak component of each element and hence the corresponding functional group was identified. Next, investigation using surface plasmon resonance (SPR) optical sensor proved that both chitosan–GO-based thin films were able to detect Co2+ as low as 0.01 ppm for both composite thin films, while the PAR had the higher binding affinity. The interaction of the Co2+ with the thin films was characterized again using XPS to confirm the functional group involved during the reaction. The XPS results proved that primary amino in the PAR–chitosan–GO thin film contributed more important role for the reaction with Co2+, as in agreement with the SPR results.


2009 ◽  
Vol 79-82 ◽  
pp. 747-750 ◽  
Author(s):  
Dong Qing Liu ◽  
Wen Wei Zheng ◽  
Hai Feng Cheng ◽  
Hai Tao Liu

Thermochromic vanadium dioxide (VO2) exhibits a semi-conducting to metallic phase transition at about 68°C, involving strong variations in electrical and optical properties. A simple method was proposed to prepare VO2 thin films from easily gained V2O5 thin films. The detailed thermodynamic calculation was done and the results show that V2O5 will decompose to VO2 when the post annealing temperature reaches 550°C at the atmospheric pressure of less than 0.06Pa. The initial V2O5 films were prepared by sol-gel method on fused-quartz substrates. Different post annealing conditions were studied. The derived VO2 thin film samples were characterized using X-ray diffraction and X-ray photoelectron spectroscopy. The electrical resistance and infrared emissivity of VO2 thin films under different temperatures were measured. The results show that the VO2 thin film derived from the V2O5 thin film annealed at 550°C for 10 hours is pure dioxide of vanadium without other valences. It was observed that the resistance of VO2 thin film with thickness about 600nm can change by 4 orders of magnitude and the 7.5-14μm emissivity can change by 0.6 during the phase transition.


2013 ◽  
Vol 295-298 ◽  
pp. 413-417 ◽  
Author(s):  
Zai Feng Shi ◽  
Su Min Zhang ◽  
Su Guo

To study the effects of substrate materials on the photocatalytic activity, TiO2films were immobilized on the inner wall surface of ceramic, glass and stainless steel tubes by sol-gel method. X-ray diffraction (XRD) results indicated that the crystal form of TiO2were all anatase type with theoretical particle size of 15 nm. According to the X-ray photoelectron spectroscopy (XPS) results, appearance of the element Na was observed which would decrease the photocatalytic activity. Scanning electron microscope (SEM) photos showed that the film coating on the ceramic and glass were even and uniform with thickness of about 300 nm and practical particle size of 20 nm to 100 nm. However, the film coating on stainless steel was hackly which would lead to diffraction of lights. The degradation rate constants of methylene blue (MB) with initial concentration of 5 mg.L-1were 0.049 min-1、0.029 min-1and 0.023 min-1with films coating on ceramic, stainless steel and glass tubes respectively. Degraded with TiO2film coating on ceramic tube, the according rate constants of phenol were 0.37, 0.14, 0.04 and 0.02 min-1for initial concentration of 2, 10, 50 and 100 mg.L-1respectively.


1984 ◽  
Vol 32 ◽  
Author(s):  
R. K. Brow ◽  
C. G. Pantano

ABSTRACTSol/gel derived silica thin films were thermally treated in NH3 for four hours at temperatures up to 1300C. The films were analyzed by ellipsometry, X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR). Over 30 mol% nitrogen was incorporated in the film treated at 1300C. Using IR and XPS analyses, -NHx groups were found to be present after low temperature treatments, while nitrogen was incorporated in an oxynitride structure after the higher temperature treatments.


2021 ◽  
Vol 2070 (1) ◽  
pp. 012098
Author(s):  
P K Ojha ◽  
S K Mishra

Abstract Vanadium dioxides are strongly correlated systems which undergo an insulator-metal transition (IMT) from a low-temperature semiconducting phase to a high-temperature metallic phase. Among them, Vanadium dioxide (VO2) undergoes IMT close to room temperature, accompanied by a structural transition resulting change of several orders of magnitude in the electrical and optical properties. Here, we present the synthesis of VO2 by sol-gel process which employs cost-effective precursors to synthesize pure phase of VO2 thin films. The synthesized thin films were characterized using an X-ray diffraction (XRD) to confirm phase purity and high resolution scanning electron microscope (HR-SEM) to study the crystallite and particle size for the synthesized films. The film’s surface was analyzed by X-ray photoelectron spectroscopy (XPS) to determine the valence state and chemical composition of vanadium dioxide.


Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1124 ◽  
Author(s):  
Chao-Feng Liu ◽  
Xin-Gui Tang ◽  
Lun-Quan Wang ◽  
Hui Tang ◽  
Yan-Ping Jiang ◽  
...  

The resistive switching (RS) characteristics of flexible films deposited on mica substrates have rarely been reported upon, especially flexible HfO2 films. A novel flexible Au/HfO2/Pt/mica resistive random access memory device was prepared by a sol-gel process, and a Au/HfO2/Pt/Ti/SiO2/Si (100) device was also prepared for comparison. The HfO2 thin films were grown into the monoclinic phase by the proper annealing process at 700 °C, demonstrated by grazing-incidence X-ray diffraction patterns. The ratio of high/low resistance (off/on) reached 1000 and 50 for the two devices, respectively, being relatively stable for the former but not for the latter. The great difference in ratios for the two devices may have been caused by different concentrations of the oxygen defect obtained by the X-ray photoelectron spectroscopy spectra indicating composition and chemical state of the HfO2 thin films. The conduction mechanism was dominated by Ohm’s law in the low resistance state, while in high resistance state, Ohmic conduction, space charge limited conduction (SCLC), and trap-filled SCLC conducted together.


2012 ◽  
Vol 1449 ◽  
Author(s):  
Chen Zhao ◽  
Dan Jiang ◽  
Shundong Bu ◽  
Jinrong Cheng

ABSTRACTFerroelectric 0.7BiFeO3-0.3PbTiO3 (BFO-PT) films were deposited on stainless steel substrates by the sol-gel method. A thin layer of PbTiO3 (PT) was introduced between the substrates and BFO-PT films in order to decrease the annealing temperature of BFO-PT films. X-ray diffraction analysis reveals that BFO-PT films could be well crystallized into the perovskite structure at about 575 oC. Scanning electron microscope (SEM) images show that BFO-PT thin films have grain size of about 50∼60 nm. Our results indicated BFO-PT films deposited on stainless steel substrates maintained the excellent ferroelectric properties with remnant polarization of about 40∼50 μC/cm2.


2013 ◽  
Vol 834-836 ◽  
pp. 112-116 ◽  
Author(s):  
Tatiana Myasoedova ◽  
G.E. Yalovega ◽  
V.V. Petrov ◽  
O.V. Zabluda ◽  
V.A. Shmatko ◽  
...  

SiOxCuOythin films were prepared by the deposition on to the Si/SiO2substrates from the alcoholic solutions employing the sol-gel technique. The various analytic techniques were applied to characterize structure and properties of the films under study . The both X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies showed the presence CuO as well as CuO2phases and formation of a dual-oxide CuSiO3with the average crystallites sizes of 35-50 nm. The conductance of the films was rather sensitive to the presence of 1-20 ppm NO2concentration at the operating temperatures in the range of 20–200◦C.


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