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Displaying 1376 - 1400 of 2361

Real-time Photoluminescence Studies of Thin Film Formation in Organic Solar Cells

February 29, 2016
Author(s)
Sebastian Engmann, Felicia A. Bokel, Hyun W. Ro, Dean M. DeLongchamp, Lee J. Richter
We present a method to study the structural evolution of organic bulk-heterojunctions via real-time, in-situ, steady state photoluminescence (PL). In-situ PL, in combination with real-time transmission and reflection measurements, allowed us to

The Structural Origin of Electron Injection Enhancements with Fulleropyrrolidine Interlayers

February 25, 2016
Author(s)
Lee J. Richter, Hyunbok Lee, Christopher McNeil, Eliot Gann, Lars Thomsen, S. Park, J. Jeong, Z. A. Page, Egle Puodziukynaite, Todd Emrick, Alejandro Briseno, John C. Stephenson, Dean M. DeLongchamp
Market demand for ubiquitous, increased functionality products at low cost (the internet of things) is spurring development in additive, solution processing of electronic devices. Performance in thin-film functional devices, be they transistors, diodes, or

Interlaboratory study towards a climate-specific test: spectroscopic characterizations of EVA in glass/EVA/glass systems

February 23, 2016
Author(s)
Jae Hyun Kim, Christopher M. Stafford, Yadong Lyu, Li C. Yu, Chiao-Chi Lin, Tinh Nguyen, Xiaohong Gu
EVA as an encapsulant material is exposed to various UV irradiation, thermal cycles, and humidity conditions. Degradation of EVA can reduce not only power generation due to yellowing, but also a structural integrity of a PV module. In order to investigate

Vertical 2D/3D Semiconductor Heterostructures based on Epitaxial Molybdenum Disulfide and Gallium Nitride

February 19, 2016
Author(s)
Dmitry A. Ruzmetov, Kehao Zhang, Gheorghe Stan, Berc Kalanyan, Ganesh R. Bhimanapati, Sarah M. Eichfeld, R A. Burke, Pankaj B. Shah, Terrance P. O'Regan, Frank J. Crowne, A. Glen Birdwell, Joshua A. Robinson, Albert Davydov, Tony G. Ivanov
When designing semiconductor heterostructures, it is expected that epitaxial alignment will facilitate low-defect interfaces and efficient vertical transport. Here, we report lattice-matched epitaxial growth of molybdenum disulfide (MoSub2) directly on

Assessing Electron Backscattered Diffraction and Confocal Raman Microscopy Strain Mapping Using Wedge-indented Si

February 17, 2016
Author(s)
Lawrence Henry Friedman, Mark D. Vaudin, Stephan J. Stranick, Gheorghe Stan, Yvonne B. Gerbig, William Alexander Osborn, Robert F. Cook
The accuracy of electron backscattered diffraction (EBSD) and confocal Raman microscopy (CRM) for small-scale strain mapping are assessed using the multi-axial strain field surrounding a wedge indentation in Si as a test vehicle. The strain field is

Super Stiff and Highly Transparent Multilayer Thin Films Prepared through Hydrogen-Bonding Layer- by-Layer Assembly of Graphene and Polymer

February 8, 2016
Author(s)
Fangming Xiang, Dorsa Parviz, Tara M. Givens, Ping Tzeng, Eric Davis, Christopher Stafford, Micah J. Green, Jaime C. Grunlan
Since its discovery in 2004, graphene has been intensely studied due to its high elastic modulus, thermal conductivity, electrical conductivity, and gas impermeability. Although it is possible to use small quantities of graphene sheets for fundamental

On the Solidification of Multicomponent Alloys

February 1, 2016
Author(s)
William J. Boettinger
Various topics taken from the author's research portfolio that involve multicomponent alloy solidification will be reviewed. Topics include: ternary eutectic solidification and Scheil-Gulliver paths in ternary systems. A case study of the solidification of

Polymer Glass-Formation in Variable Dimension

January 14, 2016
Author(s)
Jack F. Douglas, Freed Karl, Wensheng Xu
We explore the nature of glass-formation in variable spatial dimensionality (d) based on the generalized entropy theory, a synthesis of the Adam-Gibbs model with direct computation of the configurational entropy of polymer fluids using an established

Fe-catalyzed etching of exfoliated graphite through carbon hydrogenation

January 8, 2016
Author(s)
Guangjun Cheng, Christina A. Hacker, Curt A. Richter, Angela R. Hight Walker
We present an investigation on the etching of graphite catalyzed by the particles produced by dewetting Fe thin films on graphite in forming gas. Raman mapping of the etched graphite shows the thickness variation in the etched channels and reveals that the

Unexpected ?-Phase Formation in Additive Manufactured Ni-based Super Alloy

January 8, 2016
Author(s)
Yaakov S. Idell, Lyle E. Levine, Andrew J. Allen, Fan Zhang, Carelyn E. Campbell, Greg Olson, Jiadong Gong, David Snyder
An as-built and solutionized Ni-based super alloy built by additive manufacturing through a direct metal laser sintering technique is characterized to understand the microstructural differences as compared to the as-wrought alloy. The rapid solidification

Structure of Periodic Crystals and Quasicrystals in Ultrathin Films of Ba-Ti-O

January 7, 2016
Author(s)
Eric J. Cockayne, Marek Mihalkovic, Christopher L. Henley
We model the remarkable thin-film Ba-Ti-O structures formed by heat treatment of an initial perovskite BaTiO$_3$ thin film on a Pt(111) surface. All structures contain a rumpled Ti-O network with all Ti threefold coordinated with O, and with Ba occupying

ASTM Workshop on Standards & Measurements for Tissue Engineering Scaffolds

January 1, 2016
Author(s)
Carl G. Simon Jr., John Test, Michael Yaszemski, Reto Luginbuehl, Anthony Ratcliffe, Paul Tomlins
A “Workshop on Standards & Measurements for Tissue Engineering Scaffolds” was held on May 21, 2013 and was sponsored by the American Society of Testing and Materials International (ASTM International) in Indianapolis, IN. The purpose of the workshop was to

The Impact of the Crystallite Orientation Distribution on Exciton Transport in Donor-Acceptor Conjugated Polymers

December 30, 2015
Author(s)
Alexander L. Ayzner, Jianguo Mei, Anthony Appleton, Dean DeLongchamp, Alexandre Nardes, Stephanie Benight, Nikos Kopidakis, Michael F. Toney, Zhenan Bao
Conjugated polymers are widely used materials in organic photovoltaic devices. Owing to their extended electronic wavefunctions, they often form semicrystalline thin films. Although it is known that the polymer crystal orientation plays a large role in

Broadband Optical Properties of Graphene by Spectroscopic Ellipsometry

December 11, 2015
Author(s)
Wei Li, Nhan Van Nguyen, Guangjun Cheng, Angela R. Hight Walker, David J. Gundlach, Yiran Liang, boyuan Tian, Xuelei Liang, Lian-Mao Peng
The broadband (0.7 eV to 9.0 eV) optical properties of chemical-vapor-deposition (CVD) grown graphene are determined by spectroscopic ellipsometry. The optical absorption follows the fine structure constant in the energy range from 1.0 eV to 2.0 eV, but

Shape critical properties of patterned Permalloy thin films

December 7, 2015
Author(s)
Robert D. Shull, Y. P. Kabanov, V S. Gornakov, Andrew P. Chen, Valerian I. Nikitenko
The effects of shape and edges in magnetic elements with reduced dimensions on the magnetization reversal of cross- and framed cross- shaped Ni(sub79)Fe(sub21) (30mn) films were studied. Remagnetization details in the stripes of the patterned structures

Quantized Hall resistance in large-scale monolayer graphene

November 28, 2015
Author(s)
Yanfei Yang, Chiashain Chuang, Chieh W. Liu, Randolph Elmquist
Abstract: Graphene is an atomic-thickness carbon lattice that can be exfoliated from solid graphite or grown using high temperature processing methods on a variety of substrates. Many practical applications of large-area graphene, however, are limited by
Displaying 1376 - 1400 of 2361
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