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Articles 1 - 9 of 9
Full-Text Articles in Condensed Matter Physics
Investigation Of Role Of Tungsten Ions On Structural And Optical Properties Of Sodium Borosilicate Germanate Glass For Optoelectronic Applications, Mohamed Mundher, Mohammed A. Farag, Ayman A. Bendary, Mohamed Y. Hassaan, Abu Bakr El-Bediwi
Investigation Of Role Of Tungsten Ions On Structural And Optical Properties Of Sodium Borosilicate Germanate Glass For Optoelectronic Applications, Mohamed Mundher, Mohammed A. Farag, Ayman A. Bendary, Mohamed Y. Hassaan, Abu Bakr El-Bediwi
Al-Azhar Bulletin of Science
In the current work, the role of tungsten ions on the structural and optical properties of sodium borosilicate germinate glass with the composition [70 Na 2B4O7e15 SiO2e(15-x) (Ge2O3) e x (WO3) while, x ¼ 0,2,4, 6, 8 mol %] were studied. Fast quenching method were used to prepare the glass samples. Experimental and empirical density results confirm the amorphous nature of the prepared samples. Fourier transform infrared, FTIR, results showed N4 decreases as WO3 increases. These results suggest that the decreasing in non-bridging oxygen (NBO), back conversion BO4 to BO3, occur by the increase of WO3. Optical band gap show …
Functional Nanoparticles: Tin Monoxide And Molybdenum Disulfide Quantum Dots On Graphene Nanosheets, Denys Vidish
Functional Nanoparticles: Tin Monoxide And Molybdenum Disulfide Quantum Dots On Graphene Nanosheets, Denys Vidish
Electronic Thesis and Dissertation Repository
Light harvesting can be referred to the use of an ensemble of different nanoparticles, or quantum dots, or other absorbers to optimize the ability to capture a given spectrum of electromagnetic radiation (for example the solar spectrum under specific atmospheric conditions) in a light-absorbing system. To this end, different nanoparticles play complementary functions within the system and absorb or scatter light at different wavelength intervals. Light harvesting finds applications in fields as diverse as solar cells, photosynthesis and photocatalysis. Graphene supporting a set of different semiconducting nanoparticles has often been proposed as light harvesters. To further this concept, my thesis …
First-Principles Density Functional Theory Studies On Perovskite Materials, Aneer Lamichhane
First-Principles Density Functional Theory Studies On Perovskite Materials, Aneer Lamichhane
Dissertations
Perovskites are a family of materials with a diverse combination of different elements. As a consequence, they exhibit numerous functionalities such as pyroelectric, piezoelectric, ferroelectric, and ferromagnetic with applications in photovoltaic cells, LEDs, superconductivity, colossal magneto-resistance, and topological insulators. After 2009, perovskites have gained notoriety as suitable materials for solar cells and alternative candidates to silicon-based conventional solar cells. Generally, oxide perovskites exhibit good dielectric properties, halide perovskites display good photonic qualities, and chalcogenide perovskites are used in applications in solid-state lighting, sensing, and energy harvesting. In this dissertation, various types of perovskites ranging from oxide to halide are investigated …
Properties Of Si Quantum Dots, Carolyn C. F Cadogan
Properties Of Si Quantum Dots, Carolyn C. F Cadogan
Electronic Thesis and Dissertation Repository
The fundamental properties of matter in confined particles change dramatically due to quantum effects. In this work, we have explored the optical properties of silicon quantum dots (Si-QDs) embedded in Si3N4; and the role of crystallinity on the optical properties and formation of Si-QDs in Al2O3. This work examined the role of (1) annealing temperature and the composition of the film, (2) Al doping of the host Si3N4 film, (3) doping Si-QDs and (4) Al and P passivation of Si-QDs on the PL intensity of Si-QDs embedded in Si …
Optical And Scanning Probe Studies Of Isolated Poly (3-Hexylthiophene) Nanofibers, Mina Baghgarbostanabad
Optical And Scanning Probe Studies Of Isolated Poly (3-Hexylthiophene) Nanofibers, Mina Baghgarbostanabad
Doctoral Dissertations
Plastic electronics have an essential role in the future technologies owing to their compelling characteristics such as light weight, biocompatibity, low cost fabrication, and tunable optoelectronic properties. However, the performance of polymer-based devices strongly depends on the efficiency of exciton formation and dynamics that are themselves strongly sensitive to polymer molecular packing and structural order. Therefore, the current challenge in achieving high efficiency is establishing a correlation between molecular packing and exciton coupling. P3HT nanofibers represent an attractive platform for studying optical and electronic properties of exciton coupling because their nominal (highly crystalline) internal chain packing structure is known. A …
Synthesis And Characterization Of Copper Nanoparticles And Copper-Polymer Nanocomposites For Plasmonic Photovoltaic Applications, Sabastine Chukwuemeka Ezugwu
Synthesis And Characterization Of Copper Nanoparticles And Copper-Polymer Nanocomposites For Plasmonic Photovoltaic Applications, Sabastine Chukwuemeka Ezugwu
Electronic Thesis and Dissertation Repository
Deposition techniques for the fabrication of metal nanostructures influence their morphological properties, which in turn control their optical behavior. Here, copper nanoparticles (np-Cu’s) were grown using a deposition system that was specifically set up during this work, and is based on a radio frequency (RF) sputtering source that can operate at high temperature and under bias voltage. The effect of deposition conditions (RF power, chamber pressure and substrate bias voltage) on RF sputtered np-Cu’s using RF sputtering has been studied. The study included a comparison between the morphological and optical properties of as-grown np-Cu’s and thermally treated samples. The characterization …
Optical Properties Of Photopolymer Layers Doped With Aluminophosphate Nanocrystals, Elsa Leite, Tzvetanka Babeva, E Ng, Vincent Toal, Svetlana Mintova, Izabela Naydenova
Optical Properties Of Photopolymer Layers Doped With Aluminophosphate Nanocrystals, Elsa Leite, Tzvetanka Babeva, E Ng, Vincent Toal, Svetlana Mintova, Izabela Naydenova
Articles
The optical properties of photopolymer layers consisting of an acrylamide–based matrix and microporous aluminophosphate nanocrystals of AEI- type are investigated. The compatibility of the photopolymer doped with the nanoparticles is studied. The surface and volume properties of the layers with different levels of doping with microporous nanocrystals are characterized. The effective refractive indices and absorption coefficients of the doped photopolymer layers are determined and used to calculate the refractive index and porosity of pure AEI nanoparticles used as dopants. Volume transmission gratings were recorded in the doped photopolymer layers at different spatial frequencies. By spatial monitoring of the characteristic Raman …
Optical Properties Of Silica-Mfi Doped Acrylamide-Based Photopolymer, Tzvetanka Babeva, Rosen Todorov, Svetlana Mintova, Temenujka Yovcheva, Izabela Naydenova, Vincent Toal
Optical Properties Of Silica-Mfi Doped Acrylamide-Based Photopolymer, Tzvetanka Babeva, Rosen Todorov, Svetlana Mintova, Temenujka Yovcheva, Izabela Naydenova, Vincent Toal
Articles
The optical properties of acrylamide-based photopolymer doped with pure silica MFI-type zeolites are studied by refractometric and spectrophotometric means. Dynamic Light Scattering and Transmission Electron Microscopy are used for zeolite characterization and laser refractometry and White Light Interferometric profilometry are used for surface characterization of the composites. Refractive indices and absorption coefficients of composites are determined from their transmittance and reflectance spectra. The calculated dispersion curves are further used for deriving the zeolites refractive index and porosity and the latter compared to the values of total pore volume obtained from N2-sorption measurements. The impact of the doping level on the …
Optical Properties Of Charged Polymer With Nano-Sized Zeolite Inclusions, Temenujka Yovcheva, Izabela Naydenova, Ivanka Vlaeva, Rosen Todorov, Vincent Toal, Simeon Sainov
Optical Properties Of Charged Polymer With Nano-Sized Zeolite Inclusions, Temenujka Yovcheva, Izabela Naydenova, Ivanka Vlaeva, Rosen Todorov, Vincent Toal, Simeon Sainov
Conference Papers
The optical characteristics of photopolymer films doped with nanoparticles are studied. The investigated systems consist of a soft polymer matrix containing porous zeolite nanoparticles with concentrations varied in the range from 0wt.% to 7wt.%. 40μm thick layers are obtained by casting the photopolymer nanocomposite solution on glass substrates. The corona charging influence on the transmission spectra and on the surface and the effective refractive index of the dry layers is investigated.