Open Access. Powered by Scholars. Published by Universities.®

Nanoscience and Nanotechnology Commons

Open Access. Powered by Scholars. Published by Universities.®

Semiconductor and Optical Materials

PDF

2014

Institution
Keyword
Publication
Publication Type

Articles 1 - 12 of 12

Full-Text Articles in Nanoscience and Nanotechnology

Highly Transparent, Self-Cleaning, And Antireflective Nanoparticle Coatings, Corey Seth Thompson Dec 2014

Highly Transparent, Self-Cleaning, And Antireflective Nanoparticle Coatings, Corey Seth Thompson

Graduate Theses and Dissertations

Current solar panel technologies require a sheet of glass to serve as both mechanical support and to protect the cells from the environment. The reflection from the glass sheet can reflect up to 8% of the incident light, reducing the power output of the panel. Antireflective coatings can be used to allow more light to enter the panel to be converted into usable electricity. However, no solid thin film materials exhibit a low enough index of refraction to serve as antireflective coatings for common solar glass. The main goal of this research was to investigate the self-cleaning, antifogging, and antireflective …


Engineering Surface Functionality Of Nanoparticles For Biological Applications, Yi-Cheun Yeh Nov 2014

Engineering Surface Functionality Of Nanoparticles For Biological Applications, Yi-Cheun Yeh

Doctoral Dissertations

Engineering the surface functionality of nanomaterials is the key to investigate the interactions between nanomaterials and biomolecules for potent biological applications such as therapy, imaging and diagnostics. My research has been orientted to engineer both of the surface monolayers and core materials to fabricate surface-functionalized nanomaterials through the synergistic multidisciplinary approach that combine organic chemistry, materials science and biology. This thesis illustrates the design and synthesis of the surface-funcitonalized quantum dots (QDs) and gold nanoparticles (AuNPs) for the fundamental studies and practical applications. For QDs, A new class of cationic QDs with quaternary ammonium derivatives was synthesized to provide permanent …


Investigation Of The Dynamics Of Photocarriers During Photoelectrochemical Water Splitting By Combination Of Photoelectrochemistry And Transient Absorption Spectroscopy, Wen-Hua Leng Aug 2014

Investigation Of The Dynamics Of Photocarriers During Photoelectrochemical Water Splitting By Combination Of Photoelectrochemistry And Transient Absorption Spectroscopy, Wen-Hua Leng

Journal of Electrochemistry

Semiconductor photoelectrochemical hydrogen production is an important and promising technology for utilizing solar energy. The efficiency of hydrogen production depends on the efficiencies of separation and transport of photo-generated carriers. A deep understanding of the behavior of these processes has guiding significance for designing efficient solar hydrogen device. photoelectrochemical and transient absorption spectroscopy methods are powerful tool for studying the microscopic dynamics and mechanism of photocatalytic reaction. This review describes the part of the latest results of the author regarding the semiconductor photoelectrochemical hydrogen production obtained by these methods,and the problems and future research priorities in this field are proposed.


Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus, Andrew Stephens, Zhe Luo, Xianfan Xu Aug 2014

Development Of A Nanomanufacturing Process To Produce Atomically Thin Black Phosphorus, Andrew Stephens, Zhe Luo, Xianfan Xu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Atomically thin black phosphorus (phosphorene) has both unique and desirable properties that differ from bulk black phosphorus. Unlike graphene, phosphorene has a bandgap, which makes it potentially useful for applications in the next generation of transistors. Large-scale applications of phosphorene, like other 2D materials, are limited by current production methods. The most common method of making phosphorene is mechanical exfoliation, which can only produce small and irregular quantities. In this work we investigate a top-down method of producing phosphorene by using a scanning ultrafast laser to thin black phosphorus flakes. Because the bandgap of phosphorene increases as layers are removed, …


Implementing The ‘Frozen Potential’ Approach On Adept To Analyze Thin Film Solar Cells, Abhirit Kanti, Raghu Vamsi Krishna Chavali, Mark S. Lundstrom Phd, Muhammad A. Alam Phd Aug 2014

Implementing The ‘Frozen Potential’ Approach On Adept To Analyze Thin Film Solar Cells, Abhirit Kanti, Raghu Vamsi Krishna Chavali, Mark S. Lundstrom Phd, Muhammad A. Alam Phd

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thin film solar cells have higher absorption coefficients than traditional Silicon solar cells. This means that lesser material is required to produce the same power output for a given intensity of solar illumination. As a result, they are less expensive, easier to install and have a wider range of applications. Analyzing the performance of cells requires separating the current into the photocurrent and the injection current based on the ‘Superposition Principle’. For thin film solar cells, this cannot be done using the conventional method. This is because these components are interdependent, and so modeling one’s behavior requires understanding the other. …


Effects Of Nanoholes Grown By Molecular Beam Droplet Epitaxy On Electrical Properties Of Two Dimensional Electron Gas, Yusuke Hirono Aug 2014

Effects Of Nanoholes Grown By Molecular Beam Droplet Epitaxy On Electrical Properties Of Two Dimensional Electron Gas, Yusuke Hirono

Graduate Theses and Dissertations

The effects of nanoholes, grown by molecular beam droplet epitaxy, on the electrical properties of quantum well (QW) heterostructures are reported. To investigate how the depth of nanoholes affect the electrical properties of the QW heterostructures, the growth conditions for nanoholes were optimized with respect to their depth and density. Using the results of the optimization of the nanohole growth, three InGaAs pseudomorphic quantum wells with nanoholes were investigated with varied depth and a constant density. A QW heterostructure without nanoholes was grown as a reference structure. For all the samples, temperature dependent Hall effect measurements, noise studies as a …


Interfacial Interactions Between Carbon Nanoparticles And Conjugated Polymers, Yanqi Luo Aug 2014

Interfacial Interactions Between Carbon Nanoparticles And Conjugated Polymers, Yanqi Luo

Master's Theses

Conjugated polymer based electronics, a type of flexible electronic devices, can be produced from solution by traditional printing and coating processes in a roll-to-roll format such as papers and graphic films. This shows great promise for the emerging energy generation and conversion. The device performance of polymer electronics is largely dependent of crystalline structures and morphology of photoactive layers. However, the solution crystallization kinetics of conjugated polymers in the presence of electron acceptor nanoparticles has not been fully understood yet. In this study, solution crystallization kinetics of poly (3-hexylthiophene) in the presence of carbon nanotubes and graphene oxide has been …


Effects Of Conformational Transformations On Electronic Transport Properties Of Optical Molecular Switches: An Ab Initio Study, Yuan-Yuan He, Jian-Wei Zhao Jun 2014

Effects Of Conformational Transformations On Electronic Transport Properties Of Optical Molecular Switches: An Ab Initio Study, Yuan-Yuan He, Jian-Wei Zhao

Journal of Electrochemistry

A series of model molecules with 4 kinds of conformational transformations have been investigated as optical molecular switches by using density functional theory combined with nonequilibrium Green’s function method. The theoretical calculations show that molecules after conformational transformations have photoswitching characteristics. We find that the photochromic molecules with the same conformational transformation usually have a similar current on/off state when they are applied as photoshwitches. Among these transformations, the molecular switch with E(“trans”)/Z(“cis”)-isomerisation of the NN double bond has the highest current on-off ratio. The influences of the energy gap (HLG) between the highest occupied molecular orbital …


Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications, Logan Grimes Jun 2014

Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications, Logan Grimes

Master's Theses

The American Cancer Society predicts that 1,665,540 people will be diagnosed with cancer, and 585,720 people will die from cancer in 2014. One of the most common types of cancer in the United States is skin cancer. Melanoma alone is predicted to account for 10,000 of the cancer related deaths in 2014. As a highly mobile and aggressive form of cancer, melanoma is difficult to fight once it has metastasized through the body. Early detection in such varieties of cancer is critical in improving survival rates in afflicted patients. Present methods of detection rely on visual examination of suspicious regions …


Fabrication And Characterization Of Amorphous/Nanocrystalline Thin Film Composite, Benjamin Seth Newton May 2014

Fabrication And Characterization Of Amorphous/Nanocrystalline Thin Film Composite, Benjamin Seth Newton

Graduate Theses and Dissertations

Combining the absorption abilities of amorphous silicon and the electron transport capabilities of crystalline silicon would be a great advantage to not only solar cells but other semiconductor devices. In this work composite films were created using molecular beam epitaxy and electron beam deposition interchangeably as a method to create metallic precursors. Aluminum induced crystallization techniques were used to convert an amorphous silicon film with a capping layer of aluminum nanodots into a film composed of a mixture of amorphous silicon and nanocrystalline silicon. This layer was grown into the amorphous layer by cannibalizing a portion of the amorphous silicon …


Biogenic Fabrication Of Au@Ceo2 Nanocomposite With Enhanced Visible Light Activity, Mohammad Mansoob Khan Dr, S. A. Ansari, M. O. Ansari, B. K. Min, J Lee, M. H. Cho Apr 2014

Biogenic Fabrication Of Au@Ceo2 Nanocomposite With Enhanced Visible Light Activity, Mohammad Mansoob Khan Dr, S. A. Ansari, M. O. Ansari, B. K. Min, J Lee, M. H. Cho

Dr. Mohammad Mansoob Khan

This study reports a biogenic approach to the synthesis of Au@CeO2 nanocomposite using electrochemically active biofilms (EABs) in water under normal pressure and 30 °C. This work presents the results of extensive morphological, structural, optical, visible light photoelectrochemical and photocatalytic studies of Au@CeO2 nanocomposite. The presence of a large number of interfaces between Au nanoparticles and CeO2 for charge transfer is believed to play a key role in enhancing the optical and visible light photoelectrochemical and photocatalytic performance of Au@CeO2 nanocomposite. The enhanced visible light degradation of methyl orange and methylene blue by Au@CeO2 nanocomposite was much higher than that …


Band Gap Engineered Tio2 Nanoparticles For Visible Light Induced Photoelectrochemical And Photocatalytic Studies, Mohammad Mansoob Khan Dr, S A. Ansari, D Pradhan, D H. Han, J Lee, M. H. Cho Dec 2013

Band Gap Engineered Tio2 Nanoparticles For Visible Light Induced Photoelectrochemical And Photocatalytic Studies, Mohammad Mansoob Khan Dr, S A. Ansari, D Pradhan, D H. Han, J Lee, M. H. Cho

Dr. Mohammad Mansoob Khan

Visible light-active TiO2 (m-TiO2) nanoparticles were obtained by an electron beam treatment of commercial TiO2 (p-TiO2) nanoparticles. The m-TiO2 nanoparticles exhibited a distinct red-shift in the UV-visible absorption spectrum and a much narrower band gap (2.85 eV) due to defects as confirmed by diffuse reflectance spectroscopy (DRS), photoluminescence (PL), X-ray diffraction, Raman spectroscopy, electron paramagnetic resonance, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and linear scan voltammetry (LSV). The XPS revealed changes in the surface states, composition, Ti4+ to Ti3+ ratio, and oxygen deficiencies in the m-TiO2. The valence band XPS, DRS and PL results were …