scholarly journals Optical and Structural Investigation of CdSe Quantum Dots Dispersed in PVA Matrix and Photovoltaic Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Pallabi Phukan ◽  
Dulen Saikia
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Quantum Dots ◽  
Hexagonal Wurtzite Structure ◽  
Xrd Analysis ◽  
Cdse Quantum Dots ◽  
X Ray Diffraction ◽  
Morphological Studies ◽  
Transmission Electron ◽  
Particle Size Determination

CdSe quantum dots (QDs) dispersed in polyvinyl alcohol (PVA) matrix with their sizes within the quantum dot regime have been synthesized via a simple heat induced thermolysis technique. The effect of the concentrations of the cadmium source on the optical properties of CdSe/PVA thin films was investigated through UV-Vis absorption spectroscopy. The structural analysis and particle size determination as well as morphological studies of the CdSe/PVA nanocomposite thin films were done with the help of X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD analysis reveals that CdSe/PVA nanocomposite thin film has a hexagonal (wurtzite) structure. A prototype thin film solar cell of CdSe/CdTe has been synthesized and its photovoltaic parameters were measured.

Microstructure and Magnetic Properties of CoFeHfO Rich Nanocrystalline Thin Films Application for High Frequency

2007 ◽  
Vol 558-559 ◽  
pp. 975-978
Author(s):  
L.V. Tho ◽  
K.E. Lee ◽  
Cheol Gi Kim ◽  
Chong Oh Kim ◽  
W.S. Cho
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetic Properties ◽  
Rf Sputtering ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
Electrical And Magnetic Properties ◽  
Transmission Electron ◽  
Nanocrystalline Thin Films

Nanocrystalline CoFeHfO thin films have been fabricated by RF sputtering method. Co52Fe23Hf10O15 thin film is observed, exhibit good magnetic properties with magnetic coercivity (Hc) of 0.18 Oe; anisotropy fild (Hk) of 49 Oe; saturation magnetization (4лMs) of 21 kG, and electrical resistivity (ρ) of 300 01cm. The frequency response of permeability of the film is excellent. The effect of microstructure on the electrical and magnetic properties of thin film was studied using X-ray diffraction (XRD) analysis and conventional transmission electron microscopy (TEM). The results showed that excellent soft magnetic properties were associated with granular nannoscale grains of α-CoFe and α-Co(Fe) phases.

Palladium Nanowire Thin Films via Template Growth

2003 ◽  
Vol 775 ◽  
Author(s):  
Donghai Wang ◽  
David T. Johnson ◽  
Byron F. McCaughey ◽  
J. Eric Hampsey ◽  
Jibao He ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Conductive Substrate ◽  
Palladium Nanowires ◽  
Efficient Route ◽  
Silica Thin Film

AbstractPalladium nanowires have been electrodeposited into mesoporous silica thin film templates. Palladium continually grows and fills silica mesopores starting from a bottom conductive substrate, providing a ready and efficient route to fabricate a macroscopic palladium nanowire thin films for potentially use in fuel cells, electrodes, sensors, and other applications. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate it is possible to create different nanowire morphology such as bundles and swirling mesostructure based on the template pore structure.

Microstructure characteristics of non-monodisperse quantum dots: on the potential of transmission electron microscopy combined with X-ray diffraction

CrystEngComm ◽  
2020 ◽  
Vol 22 (21) ◽  
pp. 3644-3655
Author(s):  
Stefan Neumann ◽  
Christina Menter ◽  
Ahmed Salaheldin Mahmoud ◽  
Doris Segets ◽  
David Rafaja
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Cdse Quantum Dots ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure Characteristics ◽  
Scale Bridging ◽  
Transmission Electron ◽  
Hot Injection

Capability of TEM and XRD to reveal scale-bridging information about the microstructure of non-monodisperse quantum dots is illustrated on the CdSe quantum dots synthesized using an automated hot-injection method.

A Critical Investigation on the Existence of Selective Microwave Absorption in the Synthesis of CdSe Quantum Dots

2014 ◽  
Vol 67 (9) ◽  
pp. 1180 ◽  
Author(s):  
Mojtaba Mirhosseini Moghaddam ◽  
C. Oliver Kappe
Keyword(s):  
Quantum Dots ◽  
Microwave Absorption ◽  
Transmission Electron Microscopy Data ◽  
Microwave Assisted Synthesis ◽  
Cdse Quantum Dots ◽  
X Ray Diffraction ◽  
Heating And Cooling ◽  
Transmission Electron ◽  
Microscopy Data ◽  
Heating Mode

The existence of selective microwave absorption phenomena in the synthesis of CdSe quantum dots has been investigated. These types of microwave effects involving selective microwave absorption by specific reagents have recently been proposed in the microwave-assisted synthesis of various nanoparticles. In the present study, the microwave synthesis of CdSe quantum dots was investigated according to a protocol published by Washington and Strouse to clarify the presence of selective microwave heating. Importantly, control experiments involving conventional conductive heating were executed under otherwise (except for the heating mode) identical conditions, ensuring the same heating and cooling profiles, stirring rates, and reactor geometries. Comparison of powder X-ray diffraction, UV-vis, photoluminescence, and transmission electron microscopy data of the obtained CdSe quantum dots reveals that identical types of nanoparticles are obtained independently of the heating mode. Therefore, no evidence for a selective microwave absorption phenomenon could be obtained.

Fine Tuning Magnetic Properties of FePt:C Thin Films by FePt UnderLayers

2013 ◽  
Vol 313-314 ◽  
pp. 254-257
Author(s):  
Ling Fang Jin ◽  
Hong Zhuang
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Magnetic Properties ◽  
Fine Tuning ◽  
Nanocomposite Films ◽  
Nanocomposite Thin Film ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Nonepitaxially grown FePt (x)/FePt:C thin films were synthesized, where FePt (x) (x=2, 5, 8, 11, 14 nm) layers were served as underlayers and FePt:C layer was nanocomposite with thickness of 5 nm. The effect of FePt underlayer on the ordering, orientation and magnetic properties of FePt:C thin films has been investigated by adjusting FePt underlayer thicknesses from 2 nm to 14 nm. X-ray diffraction (XRD), together with transmission electron microscopy (TEM) confirmed that the desired L10 phase was formed and films were (001) textured with FePt underlayer thickness decreased less 5 nm. For 5 nm FePt:C nanocomposite thin film with 2 nm FePt underlayer, the coercivity was 8.2 KOe and the correlation length of FePt:C nanocomposite film was 67 nm. These results reveal that the better orientation and magnetic properties for FePt:C nanocomposite films can be tuned by decreasing FePt underlayer thickness.

Initial Evolution of Cobalt Silicides in The Cobalt/Amorphous-Silicon Thin Film System

1991 ◽  
Vol 230 ◽  
Author(s):  
Hideo Miura ◽  
En Ma ◽  
Carl V. Thompson
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Amorphous Silicon ◽  
Amorphous Layer ◽  
X Ray Diffraction ◽  
Silicon Thin Film ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Initial Evolution ◽  
Cobalt Silicides

AbstractThe initial phase formation sequence for reactions in cobalt/ amorphous-silicon multi-layer thin films has been investigated using a combination of differential scanning calorimetry, thin film X-ray diffraction, and transmission electron microscopy. Multilayer thin films with various overall atomic concentration ratios and various bilayer thicknesses were used in this study. It was found that crystalline CoSi is always the first phase to nucleate in the interdiffused amorphous layer which preexisted at the as-deposited coba It/amorphous-si licon interface. The CoSi nucleates at temperatures as low as about 530 K, but does not grow until the next phase, which is Co2 Si when excess Co is available, starts to nucleate and grow. The activation energy of the CoSi nucleation was found to be 1.-6±0.1 eV.

Crystallographic and Magnetic Properties of CoCrPt Thin Films Investigated Using Single-Crystal Perpendicular Magnetic Thin Film Samples

2002 ◽  
Vol 721 ◽  
Author(s):  
Masaaki Futamoto ◽  
Kouta Terayama ◽  
Katsuaki Sato ◽  
Nobuyuki Inaba ◽  
Yoshiyuki Hirayama
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetic Properties ◽  
Single Crystal ◽  
Film Plane ◽  
Magnetic Thin Film ◽  
X Ray Diffraction ◽  
Easy Magnetization ◽  
Transmission Electron ◽  
Magnetization Axis

AbstractConditions to prepare good single-crystal CoCrPt magnetic thin film with the easy magnetization axis perpendicular to the film plane were investigated using oxide single-crystal substrates, Al2O3(0001), LaAlO3(0001), mica(0001), SrTiO3(111), and MgO(111). The best CoCrPt(0001) single-crystal thin film was obtained on an Al2O3(0001) substrate employing a non-magnetic CoCrRu underlayer. The crystallographic quality of single-crystal thin film was investigated using X-ray diffraction and high-resolution transmission electron microscopy. Some intrinsic magnetic properties (Hk, Ku) were determined for the single-crystal CoCrxPty thin films for a compositional range of x=17-20at% and y=0-17at%.

scholarly journals Properties of RF Magnetron-Sputtered Copper Gallium Oxide (CuGa2O4) Thin Films

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 921
Author(s):  
Ashwin Kumar Saikumar ◽  
Sreeram Sundaresh ◽  
Shraddha Dhanraj Nehate ◽  
Kalpathy B. Sundaram
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Wavelength Region ◽  
Rf Magnetron Sputtering ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Morphological Studies ◽  
Increasing Trend ◽  
First Time ◽  
Post Deposition

Thin films of CuGa2O4 were deposited using an RF magnetron-sputtering technique for the first time. The sputtered CuGa2O4 thin films were post-deposition annealed at temperatures varying from 100 to 900 °C in a constant O2 ambience for 1.5 h. Structural and morphological studies were performed on the films using X-ray diffraction analysis (XRD) and a Field Emission Scanning Electron Microscope (FESEM). The presence of CuGa2O4 phases along with the CuO phases was confirmed from the XRD analysis. The minimum critical temperature required to promote the crystal growth in the films was identified to be 500 °C using XRD analysis. The FESEM images showed an increase in the grain size with an increase in the annealing temperature. The resistivity values of the films were calculated to range between 6.47 × 103 and 2.5 × 108 Ωcm. Optical studies were performed on all of the films using a UV-Vis spectrophotometer. The optical transmission in the 200–800 nm wavelength region was noted to decrease with an increase in the annealing temperature. The optical bandgap value was recorded to range between 3.59 and 4.5 eV and showed an increasing trend with an increase in the annealing temperature.

Photocatalytic Activity of Bilayer TiO2/ZnO and ZnO TiO2 Thin Films

2020 ◽  
Vol 1010 ◽  
pp. 411-417
Author(s):  
Rosniza Hussin ◽  
Nur Syahraain Zulkiflee ◽  
Zakiah Kamdi ◽  
Ainun Rahmahwati Ainuddin ◽  
Zawati Harun ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Photocatalytic Activity ◽  
Reaction Rate ◽  
Electronic Devices ◽  
Xrd Analysis ◽  
Optical Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Crystal

Thin film is a thin material that is resulting from the condensation of species through the deposition of atoms on the substrate. Thin films are usually used in the production of electronic devices, optical coatings, solar cells, and for decorative items. The bilayer of TiO2/ZnO and ZnO TiO2 thin films have some advantages such as can enhance the surface state and surface atomic mobility, which are useful for improving the photocatalytic activity. The motivation to a used double layer of ZnO and TiO2 is to enhance the properties and photocatalytic activity using the different deposition temperature between the layers. The structural of ZnO/TiO2 thin films were studied using X-Ray diffraction (XRD). Field Emission Scanning Electron Microscope (FESEM) was used to determine the surface morphology of ZnO/TiO2 thin films. The photocatalytic activity of ZnO/TiO2 thin films was analysed using the photodegradation of methylene blue (MB) solution. The XRD analysis revealed that highest anatase crystalline phase for TiO2 growth with orientation (1 0 1), while the ZnO crystal phase, zincite occurred at the highest intensity with (1 0 1) orientation.. The bilayer TiO2/ZnO thin film had the highest reaction rate, K, which is 0.0972 h-1 for photocatalytic activity. The characteristics of bilayer TiO2/ZnO and ZnO/TiO2 thin-film is strongly influenced by the calcination temperature and the presence and combination between the two types of materials.

Preparation of Helical Monosubstituted Polyacetylene@CdSe Quantum Dots Composite and its Application for Low Infrared Emissivity

2014 ◽  
Vol 1044-1045 ◽  
pp. 88-91
Author(s):  
Xiao Hai Bu ◽  
Yu Ming Zhou ◽  
Man He ◽  
Tao Zhang ◽  
Hu Chuan Wang
Keyword(s):  
Quantum Dots ◽  
Optically Active ◽  
Helical Conformation ◽  
Cdse Quantum Dots ◽  
Infrared Emissivity ◽  
X Ray Diffraction ◽  
Cdse Qds ◽  
Transmission Electron ◽  
Ft Ir ◽  
Ester Linkage

Helical monosubstituted polyacetylene@CdSe quantum dots (HPA@CdSe QDs) nanocomposites were fabricated by grafting helical HPA polymers onto the surface of semiconductor QDs through ester linkage. Optically active HPA derived from chiral serine was polymerized by a rhodium zwitterion catalyst, and evidently proved to adopt a predominately single-handed helical conformation. The HPA@QDs nanocomposites were characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The results indicate that the HPA matrix exhibits an enhancement in thermal stability after hybridization with CdSe QDs, while the QDs can maintain their original crystalline structure during the grafting process. The infrared emissivity property of the HPA@QDs nanocomposites at 8-14 μm was further investigated. These data demonstrated that the HPA@QDs composite film with doped CdSe QDs possesses an infrared emissivity value of 0.393, which was much lower than pristine HPA and QDs. This might be attributed to the incorporation of optically active helical HPA and semiconductor QDs in a hybrid phase and their strengthened interfacial interaction.

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