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Search Publications by: Dean DeLongchamp (Fed)

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Displaying 51 - 75 of 119

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

Effect of Regioregularity on the Semicrystalline Structure of Poly(3-hexylthiophene

August 25, 2011
Author(s)
Chad R. Snyder, Dean M. DeLongchamp, Jessica S. Henry
The impact of regioregularity in poly(3-hexylthiophene-2,5-diyl) (P3HT) on crystallization behavior and quantitative limits to possible crystal sizes is discussed, and it is explained why regioregularities must be reported for any study to be properly

Characterization of the non-uniform reaction in chemically-amplified calix[4]resorcinarene molecular resist thin films

July 19, 2011
Author(s)
Vivek M. Prabhu, Shuhui Kang, Regis J. Kline, Dean M. DeLongchamp, Daniel A. Fischer, Wen-Li Wu, Sushil K. Satija, Jing Sha, Christopher K. Ober, Peter V. Bonnesen
The ccc stereoisomer-purified tert-butoxycarbonyloxy (t-Boc) protected calix[4]resorcinarene molecular resists blended with photoacid generator exhibit a non-uniform photoacid catalyzed reaction in thin films. The surface displays a reduced reaction extent

Influence of substrate on crystallization in polythiophene/fullerene blends

January 13, 2011
Author(s)
Lee J. Richter, Christine He, David Germack, R Joseph Kline, Dean DeLongchamp, Daniel A. Fischer, Chad R. Snyder, James G. Kushmerick
The nanoscale morphology of the active layer in organic, bulk heterojunction (BHJ) solar cells is crucial to device performance. Often a combination of casting conditions and post deposition thermal treatment are used to optimize the morphology. In general

Mapping Crystal Orientation in High Performance Thienothiophene Copolymer Thin Films

December 8, 2010
Author(s)
Xinran Zhang, Steven D. Hudson, Dean M. DeLongchamp, David J. Gundlach, Martin Heeney, Iain McCulloch
Mapping of crystalline grain orientation for solution-processed semiconducting polymer thin films is key to understanding charge transport in electronic devices based on them and yet challenging. In this work, a high mobility thienothiophene copolymer

Thin film morphology of organic electronic materials

March 1, 2010
Author(s)
Xinran Zhang, Steven Hudson, Dean DeLongchamp, David J. Gundlach
Organic electronic materials are desired for low-cost printed circuits. As expected, the microstructure of these materials is crucial for their performance, such as charge-carrier mobility. These materials typically comprise anisotropic molecules, and the