scholarly journals Hybrid Sol-Gel Matrices Doped with Colorimetric/Fluorimetric Imidazole Derivatives

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3401
Author(s):  
Rui P. C. L. Sousa ◽  
Rita B. Figueira ◽  
Bárbara R. Gomes ◽  
Sara Sousa ◽  
R. Cristina M. Ferreira ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Synergetic Effect ◽  
Maximum Absorption ◽  
Imidazole Derivatives ◽  
The Matrix ◽  
Imidazole Compounds ◽  
Maximum Absorption Wavelength ◽  
Intrinsic Emission

Organic-inorganic hybrids (OIH) are materials that can be easily synthesized by the sol-gel method and combine the advantages of organic and inorganic moieties within a single polymeric matrix. Imidazole derivatives are versatile organic compounds that can change their optical properties with the variation of pH due to the protonation or deprotonation of the nitrogen atoms. This work reports the preparation of different OIHs doped with different contents of two imidazole compounds (3a,b). The obtained materials were characterized structurally by FTIR, and the dielectric properties were studied by electrochemical impedance spectroscopy. The optical properties were studied by UV-Vis absorption and fluorescence spectroscopies. The FTIR analysis showed that the presence of the imidazole does not change the structural properties of the matrices. The normalized resistance values obtained for the doped matrices ranged between 8.57 and 9.32 Ω cm2, all being higher than the undoped matrix. The σ ranged between 9.49 and 10.28 S cm−1, being all higher than the pure OIH samples. Compound 3a showed a maximum absorption peak at 390 nm, which is present in the OIH spectra, proving the presence of the compound. In the case of compound 3b, a maximum absorption wavelength at 412 nm was found, and the compound peak was not clear, which may indicate that an interaction between the compound and the matrix occurred. A synergetic effect between the intrinsic emission of the matrix and the fluorescence of 3a is found on the OIH-doped matrices.

Incorporation of CdTe Nanocrystals into Metal Oxide Matrices Towards Inorganic Nanocomposite Materials

2018 ◽  
Vol 232 (9-11) ◽  
pp. 1335-1352 ◽  
Author(s):  
Elena Frolova ◽  
Tobias Otto ◽  
Nikolai Gaponik ◽  
Vladimir Lesnyak
Keyword(s):  
Optical Properties ◽  
Metal Oxide ◽  
Optical Switching ◽  
Sol Gel ◽  
Visible Region ◽  
Point Of View ◽  
Cdte Nanocrystals ◽  
Optically Transparent ◽  
The Matrix ◽  
Heating Up

Abstract In this work we present a technique of incorporation of semiconductor CdTe nanocrystals (NCs) into metal oxide matrices prepared by inorganic sol-gel method. As the matrices, we chose alumina and aluminum tin oxide, which are optically transparent in the visible region. Among them the first is electrically insulating, while the second is conductive and thus can be used in optoelectronic devices. We found optimal synthetic parameters allowing us to maintain optical properties of the NCs in both matrices even after heating up to 150°C in air. Therefore, in our approach we overcame a common problem of degradation of the optical properties of semiconductor NCs in oxide matrices as a result of the incorporation and subsequent interaction with the matrix. The resulting materials were characterized in detail from the point of view of their optical and structural properties. Based on the results obtained, we suggest the formation mechanism of these materials. Semiconductor NCs embedded in robust and optically transparent metal oxides offer promising applications in optical switching, optical filtering, waveguides, light emitting diodes, and solar concentrators.

Protection of Aluminium Alloys via Hybrid Sol-Gel Coatings with Encapsulated Organic Corrosion Inhibitors

2006 ◽  
Vol 519-521 ◽  
pp. 661-666 ◽  
Author(s):  
A.N. Khramov ◽  
V.N. Balbyshev ◽  
R.A. Mantz
Keyword(s):  
Corrosion Protection ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Substrate Surface ◽  
Sol Gel ◽  
Matrix Material ◽  
The Matrix ◽  
Aluminum Alloy 2024 ◽  
Structural Hybrid ◽  
Organic Corrosion Inhibitors

Several heterocyclic organic corrosion inhibitors that contain ionazible functional group were encapsulated into nano-structural hybrid organo-silicate coating to improve its corrosion protection performance on aluminum alloy 2024-T3 substrate. When the coating is formed on the substrate surface, it serves simultaneously as protective barrier and as a reservoir for leachable corrosion inhibitor that is stored and released through the mechanism of reversible ionic interaction with the matrix material. The efficiency of active corrosion protection for these coating systems was examined by electrochemical methods including potentiodynamic polarization (PDS) and electrochemical impedance spectroscopy (EIS). The effects of chemical structure and the loading concentration of the inhibitor within the coating were determined.

Structural/Property Relationships for Optical Materials

1993 ◽  
Vol 329 ◽  
Author(s):  
Vivien D.
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Electronic Structure ◽  
Chemical Composition ◽  
Field Strength ◽  
Optical Materials ◽  
Site Occupancy ◽  
Laser Materials ◽  
Crystal Field Strength ◽  
The Matrix

AbstractIn this paper the relationships between the crystal structure, chemical composition and electronic structure of laser materials, and their optical properties are discussed. A brief description is given of the different laser activators and of the influence of the matrix on laser characteristics in terms of crystal field strength, symmetry, covalency and phonon frequencies. The last part of the paper lays emphasis on the means to optimize the matrix-activator properties such as control of the oxidation state and site occupancy of the activator and influence of its concentration.

STRUCTURAL, OPTICAL PROPERTIES AND PHOTOCATALYTIC ACTIVITY OF NANOCRYSTALLINE TiO2 THIN FILMS DEPOSITED BY SOL-GEL SPIN COATING

2019 ◽  
Vol 7 (1) ◽  
pp. 28
Author(s):  
KOMARAIAH DURGAM ◽  
RADHA EPPA ◽  
REDDY M. V. RAMANA ◽  
KUMAR J. SIVA ◽  
R. SAYANNA ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Photocatalytic Activity ◽  
Spin Coating ◽  
Sol Gel ◽  
Tio2 Thin Films ◽  
Nanocrystalline Tio2

Preparation and Optical Properties of CuAlO2 Microcrys-tallites by Complexing Sol-Gel

2011 ◽  
Vol 26 (3) ◽  
pp. 275-280
Author(s):  
Kang LI ◽  
Jian-Feng HUANG ◽  
Li-Yun CAO ◽  
Bo WANG ◽  
Zhe-Yong SHI
Keyword(s):  
Optical Properties ◽  
Sol Gel

Sol-Gel Synthesis, Structure and Optical Properties of Nickel-Manganese Ferrites

2019 ◽  
Vol 11 (3) ◽  
pp. 03021-1-03021-5
Author(s):  
V. S. Bushkova ◽  
◽  
I. P. Yaremiy ◽  
B. K. Ostafiychuk ◽  
N. I. Riznychuk ◽  
...  
Keyword(s):  
Optical Properties ◽  
Sol Gel ◽  
Sol Gel Synthesis ◽  
Nickel Manganese

Sol-gel growth of Ni doped CdS on glass substrates: effect of spin coating speed and dopant concentration

2020 ◽  
Vol 10 ◽  
Author(s):  
Atefeh Nazari Setayesh ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spin Coating ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Rotation Speed ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Glass Substrates

Background: In this work, CdS thin films were synthesized by sol-gel method (spin coating technique) on glass substrates to investigate the optical behavior of the film. Methods: Different substrate spin coating speeds of 2400, 3000, 3600 rpm and different Ni dopant concentrations of 0 wt.%, 2.5 wt.%, 5 wt.%) were investigated. The optical properties of thin films such as refraction index, extinction coefficient, dielectric constant and optical band gap energy of the layers were discussed using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. Results: It can be deduced that substrate rotation speed and dopant concentration has influenced the optical properties of thin films. By decreasing rotation speed of the substrate which results in films with more thicknesses, more optical interferences were appeared in the results. Conclusion: The samples doped with Ni comparing to pure ones have had more optical band gap energy.

scholarly journals Influence of HAP on the Morpho-Structural Properties and Corrosion Resistance of ZrO2-Based Composites for Biomedical Applications

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 202
Author(s):  
Réka Barabás ◽  
Carmen Ioana Fort ◽  
Graziella Liana Turdean ◽  
Liliana Bizo
Keyword(s):  
Electrochemical Impedance ◽  
Artificial Saliva ◽  
Synergetic Effect ◽  
Composite Layer ◽  
Charge Transfer Resistance ◽  
Processing Route ◽  
Dental Alloys ◽  
Metallic Electrode ◽  
Transfer Resistance ◽  
X Ray

In the present work, ZrO2-based composites were prepared by adding different amounts of antibacterial magnesium oxide and bioactive and biocompatible hydroxyapatite (HAP) to the inert zirconia. The composites were synthesized by the conventional ceramic processing route and morpho-structurally analyzed by X-ray powder diffraction (XRPD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Two metallic dental alloys (i.e., Ni–Cr and Co–Cr) coated with a chitosan (Chit) membrane containing the prepared composites were exposed to aerated artificial saliva solutions of different pHs (i.e., 4.3, 5, 6) and the corrosion resistances were investigated by electrochemical impedance spectroscopy technique. The obtained results using the two investigated metallic dental alloys shown quasi-similar anticorrosive properties, having quasi-similar charge transfer resistance, when coated with different ZrO2-based composites. This behavior could be explained by the synergetic effect between the diffusion process through the Chit-composite layer and the roughness of the metallic electrode surface.

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