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Search Publications by: Dean DeLongchamp (Fed)

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Displaying 101 - 125 of 231

Interrogating the Carbon and Oxygen K-edge NEXAFS of a CO2-dosed Hyperbranched Aminosilica

December 19, 2014
Author(s)
Laura Espinal, Martin L. Green, Dean M. DeLongchamp, Watcharop Chaikittisilp, Jarod C. Horn, Miles Sakwa-Novak, Cherno Jaye, Daniel A. Fischer, Nicholas Brunelli, Christopher Jones
Near edge x-ray absorption fine structure (NEXAFS) spectroscopy was used to study the adsorption of CO2 in a hyperbranched aminosilica (HAS) compound, a porous solid state material with great potential for carbon capture applications. After dosing a

In-situ morphology studies of the mechanism for solution additive effects on the formation of bulk heterojunction films.

September 29, 2014
Author(s)
Lee J. Richter, Dean M. DeLongchamp, Kang W. Chou, Aram Amassian, A Hexemer, Eric Schaible, Felicia A. Bokel, Sebastian Engmann
The most successful active film morphology in organic photovoltaics is the bulk heterojunction (BHJ). The performance of a BHJ arises from a complex interplay of the spatial organization of the segregated donor and acceptor phases and the local order

Characterization of Buried Structure in Directed Self Assembly Block Copolymers

July 30, 2014
Author(s)
Daniel F. Sunday, Matthew R. Hammond, Chengqing C. Wang, Wen-Li Wu, Dean M. DeLongchamp, Regis J. Kline, Melia Tjio, Joy Cheng, Jed W. Pitera
The directed self assembly (DSA) of block copolymers (BCP) can multiply or subdivide the pitch of a lithographically defined chemical or topological pattern and is a resolution enhancement candidate to augment conventional lithography for patterning sub-20

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

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

Measuring order in regioregular poly(3-hexylthiophene) with solid-state 13C CPMAS NMR

January 10, 2014
Author(s)
Ryan C. Nieuwendaal, Chad R. Snyder, Dean M. DeLongchamp
We report on details of molecular packing in high molar mass poly(3-hexylthiophene) (P3HT) by solid-state 13C {1H} cross-polarization magic angle spinning (CPMAS) NMR measurements. The degree of polymer order was estimated for two films of varied drying

Vertically Segregated Structure and Properties of small molecule-polymer blend semiconductors for organic thin film transistors

August 27, 2012
Author(s)
Nayool Shin, Dean DeLongchamp, Jihoon Kang, Regis J. Kline, Lee J. Richter, Vivek Prabhu, Balaji Purushothamanc, John E. Anthony, Do Y. Yoon
The phase-segregated structure and the electrical properties of thin film blends of the small-molecule semiconductor fluorinated 5,11-bis(triethylsilylethynyl) anthradithiophene with insulating binder polymers were studied for organic thin film transistor

Polymer-Fullerene Mixing in Organic Solar Cells

August 2, 2012
Author(s)
Hyun Wook Ro, Bulent Akgun, Regis J. Kline, Chad R. Snyder, Sushil K. Satija, Christopher L. Soles, Dean M. DeLongchamp, Michael F. Toney, Alexander L. Ayzner, Brendan T. O'Connor, Matthew Hammond
The mixing behavior of the hole and electron transporting materials in bulk heterojunction (BHJ) organic photovoltaic (OPV) blends plays a key role in determining the nanoscale morphology, which is believed to be a decisive factor in determining device

Measuring domain sizes and compositional heterogeneities in P3HT-PCBM bulk heterojunction thin films with 1H spin diffusion NMR spectroscopy

March 21, 2012
Author(s)
Ryan C. Nieuwendaal, Hyun Wook Ro, David Germack, Regis J. Kline, Calvin Chan, Amit K. Agrawal, David J. Gundlach, David L. VanderHart, Dean M. DeLongchamp
In this manuscript we show that 1H spin diffusion NMR is a valuable method for estimating the domain sizes in thin films of a polymer-fullerene blend for bulk heterojunction (BHJ) photovoltaics. Variations in common BHJ film processing parameters have

Nanoscale structure measurements for polymer-fullerene photovoltaics

February 3, 2012
Author(s)
Dean M. DeLongchamp, Regis J. Kline, Andrew A. Herzing
This review covers methods to measure key aspects of nanoscale structure in organic photovoltaic devices based on polymer-fullerene bulk heterojunctions. The importance of nanoscale structure to the power conversion efficiency and stability of these

Molecular Order in High-Efficiency Polymer/Fullerene Bulk Heterojunction Solar Cells

September 22, 2011
Author(s)
Matthew R. Hammond, Regis J. Kline, Andrew A. Herzing, Lee J. Richter, David Germack, Hyun W. Ro, Christopher L. Soles, Daniel A. Fischer, Tao Xu, Luping Yu, Michael F. Toney, Dean M. DeLongchamp
We report quantitative measurements of ordering, molecular orientation, and nanoscale morphology in the active layer of bulk heterojunction organic photovoltaic cells based on a thieno[3,4-b]thiophene-alt-benzodithiophene copolymer (PTB7), which has been