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A High-Yield Synthesis Of Chalcopyrite Cuins2 Nanoparticles With Exceptional Size Control, Aaron Thurber, Alex Punnoose
A High-Yield Synthesis Of Chalcopyrite Cuins2 Nanoparticles With Exceptional Size Control, Aaron Thurber, Alex Punnoose
Physics Faculty Publications and Presentations
We report high-yield and efficient size-controlled syntheses of Chalcopyrite CuInS2 nanoparticles by decomposing molecular single source precursors (SSPs) via microwave irradiation in the presence of 1,2-ethanedithiol at reaction temperatures as low as 100◦C and times as short as 30 minutes. The nanoparticles sizes were 1.8nm to 10.8 nm as reaction temperatures were varied from 100◦C to 200◦C with the bandgaps from 2.71 eV to 1.28 eV with good size control and high yields (64%–95%). The resulting nanoparticles were analyzed by XRD, UV-Vis, ICP-OES, XPS, SEM, EDS, and HRTEM. Titration studies by 1H NMR using SSP 1 with 1,2-ethanedithiol …
A 236-Ghz Fe3+ Epr Study Of Nanoparticles Of The Ferromagnetic Room-Temperature Semiconductor Sn1-XFeXO2 (X = 0.005), Sushil K. Misra, S. I. Andronenko, Alex Punnoose, Dmitry Tipikin, J. H. Freed
A 236-Ghz Fe3+ Epr Study Of Nanoparticles Of The Ferromagnetic Room-Temperature Semiconductor Sn1-XFeXO2 (X = 0.005), Sushil K. Misra, S. I. Andronenko, Alex Punnoose, Dmitry Tipikin, J. H. Freed
Physics Faculty Publications and Presentations
High-frequency (236 GHz) electron paramagnetic resonance (EPR) studies of Fe3+ ions at 255 K are reported in a Sn1-xFexO2 powder with x = 0.005, which is a ferromagnetic semiconductor at room temperature. The observed EPR spectrum can be simulated reasonably well as the overlap of spectra due to four magnetically inequivalent high-spin (HS) Fe3+ ions (S = 5/2). The spectrum intensity is calculated, using the overlap I(BL) + (I(HS1) + I(HS2) + I(HS3) + I(HS4)) 9 x e-0.00001xB, where B is the magnetic field intensity …
Transition From N-Type To P-Type Destroys Ferromagnetism In Semiconducting Sn1-XCoXO2 And Sn1-XCrXO2 Nanoparticles, C. Van Komen, A. Punnoose, M. S. Seehra
Transition From N-Type To P-Type Destroys Ferromagnetism In Semiconducting Sn1-XCoXO2 And Sn1-XCrXO2 Nanoparticles, C. Van Komen, A. Punnoose, M. S. Seehra
Physics Faculty Publications and Presentations
This work reports strong correlations between the structural, magnetic and electronic properties of room temperature ferromagnets (RTFM) Sn1-xCoxO2 and Sn1-xCrxO2 for x = 0 to 0.1. The samples prepared by the sol-gel chemical method show RTFM for x < xL with the limiting concentration xL = 0.01 for Co doping and xL = 0.025 for Cr doping. As doping level x is increased from x = 0, the magnetic moment per ion, μ, increases and the lattice volume VL decreases up to x = xL. …
The Influences Of Cell Type And Zno Nanoparticle Size On Immune Cell Cytotoxicity And Cytokine Induction, Cory Hanley, Aaron Thurber, Charles Hanna, Alex Punnoose, Jianhui Zhang, Denise G. Wingett
The Influences Of Cell Type And Zno Nanoparticle Size On Immune Cell Cytotoxicity And Cytokine Induction, Cory Hanley, Aaron Thurber, Charles Hanna, Alex Punnoose, Jianhui Zhang, Denise G. Wingett
Physics Faculty Publications and Presentations
Nanotechnology represents a new and enabling platform that promises to provide a range of innovative technologies for biological applications. ZnO nanoparticles of controlled size were synthesized, and their cytotoxicity towards different human immune cells evaluated. A differential cytotoxic response between human immune cell subsets was observed, with lymphocytes being the most resistant and monocytes being the most susceptible to ZnO nanoparticle-induced toxicity. Significant differences were also observed between previously activated memory lymphocytes and naive lymphocytes, indicating a relationship between cell-cycle potential and nanoparticle susceptibility. Mechanisms of toxicity involve the generation of reactive oxygen species, with monocytes displaying the highest levels, …
Separation Of Topographic Features From Magnetic Force Images Using Capacitive Coupling Effect, Byung I. Kim
Separation Of Topographic Features From Magnetic Force Images Using Capacitive Coupling Effect, Byung I. Kim
Physics Faculty Publications and Presentations
Separation of topographic features from magnetic images has been an issue for the past two decades in magnetic force microscopy (MFM). The frequent pickups of the topographic features are interpreted as transitions of the tip between bistable states of the tip-sample assembly in the noncontact and tapping regions. MFM using electrostatic force modulation demonstrates the separation of the topographic features from the magnetic images by removing the tapping state from the bistable states through the introduction of a capacitive coupling.