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Time-Resolved Sensitivity of a Cadmium-Doped Copper Oxide Thin Film as a Chlorine Gas Detector

Alotibi Turki, Shirbeeny Waleed, Alshahrie Ahmed, Aida Mohammed, Iqbal Jawid

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 2

365--373

EN

Due to its strong affinity for chlorine gas, Cd can potentially form CdCl2. Cd-doped CuO thin films are sensitive to chlorine gas, as careful inclusion of Cd in the CuO crystal structure modifies the energy gap depending on the dopant concentration. We employed spray pyrolysis to deposit Cd-doped CuO on FTO (Fluorine Tin Oxide) while heating the substrate to 500 oC. The XRD (X-ray Diffraction) analysis revealed that Cd was interstitially incorporated in the CuO lattice structure, as verified by SEM (Scanning Electron Microscopy imaging). The photoluminescence study demonstrated that increasing the Cd concentration in CuO resulted in higher emission intensity, providing valuable insights into Cu2+ and O2- energy levels. Exposing a Cd-doped CuO thin film to chlorine gas modifies the bandgap, depending on the Cd concentration. The fluctuation in the bandgap energy of copper oxide doped with cadmium indicates the chlorine gas concentration nearby. Time-resolved measurements for the I-V characteristics of the thin film revealed considerable current variation during the exposure to chlorine gas.

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The Effect of Layer Thickness on the Reflectance of a Quasi One-Dimensional Composite Built with Zr55Cu30Ni5Al10 Amorphous Alloy and Epoxy Resin

Garus Sebastian, Sochacki Wojciech

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 2

503--510

EN

The study examined the impact of the angle of incidence of mechanical waves on various types of quasi one-dimensional superlattice. Binary periodic structure, quasi-periodic distribution of Thue-Morse layers and Severin’s aperiodic multilayer were used. Using the concatenation and recursive rules, the distribution of layers was determined for individual structure types for generation numbers equal to 3, 4 and 5. The structures were selected so that the thickness of the composite was the same for each type of distribution for a given generation number value. Transfer Matrix Method algorithm was used to determine reflectance. The band structure of reflectance has been demonstrated for incidence angles up to 90 degrees at mechanical wave frequencies up to 50 kHz. The existence of wide bands of high reflectance above the acoustic frequencies was demonstrated for the analyzed structures. Increasing the layer thickness caused an inhomogeneous shifts of transmission peaks towards lower frequencies.

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Enhancement of electronic, photophysical and optical properties of 5,5′-Dibromo-2,2′-bithiophene molecule : new aspect to molecular design

Muz İ., Kurban M.

Opto-Electronics Review

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2019

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Vol. 27, No. 2

113--118

EN

The aims of this study were to enhance electronic, photophysical and optical properties of molecular semiconductors. For this purpose, the isomers of the B-doped molecule (5,5′-Dibromo-2,2′-bithiophene) have been investigated by density functional theory (DFT) based on B3LYP/6-311++G** level of theory. The isomers were first calculated using kick algorithm. The most stable isomers of the B-doped molecule are presented depending on the binding energy, fragmentation energy, ionization potential, electron affinity, chemical hardness, refractive index, radial distribution function and HOMO-LUMO energy gap based on DFT. Ultraviolet-visible (UV–vis) spectra have been also researched by time-dependent (TD) DFT calculations. The value of a band gap for isomer with the lowest total energy decreases from 4.20 to 3.47 eV while the maximum peaks of the absorbance and emission increase from 292 to 324 nm and 392 to 440 nm with boron doped into 5,5′-Dibromo-2,2′-bithiophene. Obtained results reveal that the B-doped molecule has more desirable optoelectronic properties than the pure molecule.

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Modelling of electronic and optical properties of Cu2SnS3 quantum dots for optoelectronics applications

Ahamed M. Irshad, Kumar K. Sathish

Materials Science Poland

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2019

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Vol. 37, No. 1

108--115

EN

Copper tin sulfide (Cu2SnS3) is a unique semiconductor, whose nanocrystals have attracted researchers’ attention for its tunable energy bandgap and wavelength in visible and near infrared range. Quantum dots which are fabricated from this material are highly suitable for optoelectronics and solar cell applications. This paper discusses the tunable energy bandgap, exciton Bohr radius and wavelength range of wurtzite structure of Cu2SnS3quantum dots to assess the opportunity to use them in optoelectronics applications. The considerations show that the mole fraction of copper increases as energy bandgap decreases and tunable energy bandgap of this quantum dot material is inversely proportional to the wavelength.