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Displaying 626 - 650 of 1856

Fullerene-free polymer solar cells with strongly reduced bimolecular recombination and field- independent charge carrier generation

August 21, 2014
Author(s)
Steffen Roland, Marcel Schubert, Brian A. Collins, Jona Kurpiers, Zhihua Chen, Antonio Facchetti, Harald Ade, Dieter Neher
Photogeneration, recombination and transport of free charge carriers in all-polymer bulk heterojunction solar cells incorporating P3HT as donor and P(NDI2OD-T2) as acceptor polymer have been investigated by the use of time delayed collection field (TDCF)

Combining nanocalorimetry and dynamic transmission electron microscopy for in situ characterization of materials processes under rapid heating and cooling

August 18, 2014
Author(s)
Michael D. Grapes, Thomas LaGrange, Lawrence Henry Friedman, Bryan W. Reed, Geoffrey H. Campbell, Timothy P. Weihs, David A. LaVan
Nanocalorimetry is a chip-based thermal analysis technique capable of analyzing endothermic and exothermic reactions at very high heating and cooling rates. Here we couple a nanocalorimeter with an extremely fast in situ microstructural characterization

Device-Level PBTI-induced Timing Jitter Increase in Circuit-Speed Random Logic Operation

July 31, 2014
Author(s)
Jiwu Lu, Canute I. Vaz, Jason P. Campbell, Jason T. Ryan, Kin P. Cheung, Guangfan Jiao, Gennadi Bersuker, Chadwin D. Young
We utilize eye-diagram measurements of timing jitter to investigate the impact of PBTI in devices subject to DC as well as ring oscillator (RO) and pseudo-random binary sequence (PRBS) stress waveforms. We observe that RO measurements miss the relevant

Ontology Analysis if Global Gene Expression Differences of Human Bone Marrow Stromal Cells Cultured on 3D Scaffolds or 2D Films

July 31, 2014
Author(s)
Bryan A. Baker, Patrick S. Pine, Kaushik Chatterjee, Girish Kumar, Jennifer H. McDaniel, Marc L. Salit, Carl G. Simon Jr.
Differences in gene expression of human bone marrow stromal cells (hBMSCs) during culture in three-dimensional (3D) nanofiber scaffolds or on two-dimensional (2D) films were investigated via pathway analysis of microarray mRNA expression profiles. Previous

Dielectric characterization by microwave cavity perturbation corrected for non-uniform fields

July 23, 2014
Author(s)
Nathan D. Orloff, Jan Obrzut, Christian J. Long, Thomas F. Lam, James C. Booth, David R. Novotny, James A. Liddle, Pavel Kabos
The non-uniform fields that occur due to the slot in the cavity through which the sample is inserted and those due to the sample geometry itself decrease the accuracy of dielectric characterization by cavity perturbation at microwave frequencies. To

Comparing Matched Polymer:Fullerene Solar Cells Made by Solution-Sequential Processing and Traditional Blend Casting: Nanoscale Structure and Device Performance

July 8, 2014
Author(s)
Andrew Herzing, Steven A. Hawks, Jordan C. Aguirre, Laura T. Schelhas, Robert Thompson, Rachel Huber, Amy Ferreira, Guangye Zhang, Robert A. Street, Sarah Tolbert, Benjamin Schwartz
Efficient bulk heterojunction (BHJ) solar cells based on polymer:fullerene photoactive layers can be created either by traditional blend casting (BC), where the components are mixed together in solution before being cast, or by solution-sequential

Cathodoluminescence Quantum Efficiency of Quantum Dot Thin Films

July 7, 2014
Author(s)
Heayoung Yoon, Christopher C. Bohn, Youngmin Lee, Seung H. Ko, Jonathan S. Steckel, Seth Coe-Sullivan, Nikolai B. Zhitenev
A thin film of quantum dots (QD) was used to visualize the local photo-response of polycrystalline CdTe solar cells by down-converting an electron beam of high energy to photons of visible light. The efficient photon generation in the QD film is compared

Accurate Fast Capacitance Measurements for Reliable Device Characterization

July 1, 2014
Author(s)
Pragya R. Shrestha, Kin P. Cheung, Jason P. Campbell, Jason T. Ryan, Helmut Baumgart
As device dimensions continue to scale, transient phenomena are becoming increasingly more important to understand for both performance and reliability considerations. Recently, fast capacitances versus voltage (CV) measurements have been gaining attention

DNA-Controlled Carbon Nanotube Partition in Polymer Aqueous Two-Phase Systems

June 28, 2014
Author(s)
Geyou Ao, Constantine Y. Khripin, Ming Zheng
Sorting single-wall carbon nanotubes (SWCNTs) of different chiralities is both scientifically interesting and technologically important. Recent studies have shown that polymer aqueous two-phase extraction is a very effective way to achieve nanotube sorting

Interface Engineering to Control Magnetic Field Effects of Organic-Based Devices by Using a Molecular Self-Assembled Monolayer

June 26, 2014
Author(s)
Hyuk-Jae Jang, Sujitra J. Pookpanratana, Alyssa N. Brigeman, Regis J. Kline, James I. Basham, David J. Gundlach, Christina A. Hacker, Oleg A. Kirillov, Oana Jurchescu, Curt A. Richter
Organic semiconductors hold immense promise for the development of a wide range of innovative devices with their excellent electronic and manufacturing characteristics. Of particular interest are non-magnetic organic semiconductors that show unusual

Effects of Temperature on Surface Accumulation and Release of Silica Nanoparticles in an Epoxy Nanocoating Exposed to UV Radiation

June 16, 2014
Author(s)
Chun-Chieh Tien, Ching-Hsuan Chang, Bernard Hao-Chih Liu, Deborah Jacobs, Savelas A. Rabb, Lee L. Yu, Tinh Nguyen, Li Piin Sung
Polymer nanocoatings are increasingly used outdoors and in harsh environments. However, because most common polymers degraded by the weathering elements, nanoparticles in polymer nanocoatings may be released into the environments. Such nanoparticle release

Morphological origin of charge transport anisotropy in aligned polythiophene thin films

June 11, 2014
Author(s)
Brendan T. O'Connor, Obadiah G. Reid, Xinran Zhang, Regis J. Kline, Lee J. Richter, David J. Gundlach, Dean DeLongchamp, Michael F. Toney, Nikos Kopidakis, Garry Rumbles
The morphological origin of anisotropic charge transport in uniaxially strain aligned poly(3-hexylthiophene) (P3HT) films is investigated. The macroscale field effect mobility anisotropy is measured in an organic thin film transistor (OTFT) configuration

Spray-deposition and photopolymerization of organic-inorganic thiol-ene resins for fabrication of superamphiphobic surfaces

June 9, 2014
Author(s)
Li Xiong, Laken Kendrick, Hannele Heusser, Bradley J. Sparks, Christopher Stafford, James T. Goetz, Sergei Nazarenko, Derek L. Patton
Superamphiphobic surfaces, exhibiting high contact angles and low contact angle hysteresis to both water and low surface tension liquids, have attracted a great deal of attention in recent years due to the importance in many practical applications. In this

Energy Control Paradigm for Compliance-Free Reliable Operation of RRAM

June 5, 2014
Author(s)
Pragya R. Shrestha, David M. Nminibapiel, Jihong Kim, Jason P. Campbell, Kin P. Cheung, Shweta Deora, G. Bersuker, Helmut Baumgart
We demonstrate reliable RRAM operation by controlling the forming energy via short voltage pulses (picosecond range) which eliminates the need for a current compliance element. We further show that the dissipated energy during forming and SET/RESET

A study of shear banding in polymer solutions

June 4, 2014
Author(s)
Michael E. Cromer, Glenn Fredrickson, Gary Leal
In a recent letter (Cromer et al. Phys. Fluids 2013) we showed, for the first time, the existence of a steady shear-banded velocity profile for a polymer solution with an underlying monotonic constitutive curve. The driving mechanism is the coupling of the

Quantifying Crystallinity in High Molar Mass Poly(3-hexylthiophene)

June 3, 2014
Author(s)
Chad R. Snyder, Ryan C. Nieuwendaal, Dean M. DeLongchamp, Christine K. Luscombe, Prakash Sista, Shane D. Boyd
We extend a recent comprehensive study of 3-hexylthiophene oligomers to high molar mass poly(3-hexylthiophene) (P3HT) fractions, such as those used in organic photovoltaic devices. Through a combination of differential scanning calorimetry (DSC) and 13C

Predicting the J-V Curve in Organic Photovoltaics Using Impedance Spectroscopy

June 2, 2014
Author(s)
James I. Basham, Thomas N. Jackson, David J. Gundlach
We employ impedance spectroscopy as a method to predict the current-voltage curve in organic photovoltaics. This technique allows the quantification of the recombination rate, series resistance, carrier density and lifetime very close to normal operating

Circuit Speed Timing Jitter Increase in Random Logic Operation after NBTI Stress

June 1, 2014
Author(s)
Guangfan Jiao, Jiwu Lu, Jason Campbell, Jason Ryan, Kin P. Cheung, Chadwin D. Young, Gennadi Bersuker
Recently, much effort has been spent trying to relate NBTI observations to real circuit impacts. While many of these efforts rely on circuit simulation to bridge this gap, an experimental approach is, of course, preferred. In this study we provide this

Microsensors for Mars: Trace Analyte Detection in a Simulated Martian Environment

May 23, 2014
Author(s)
Kurt D. Benkstein, Phillip H. Rogers, Christopher B. Montgomery, C. Jin, Baranidharan Raman, Stephen Semancik
Chemiresistive microsensor arrays are being developed and tested in a simulated Martian environment. Target analyte species include trace small molecules that may indicate current geological or, potentially, biological activity on Mars. The sensing films
Displaying 626 - 650 of 1856