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Search Publications by: Dean DeLongchamp (Fed)

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Displaying 76 - 100 of 119

Substrate-dependent interface composition and charge transport in films for organic photovoltaics

June 9, 2009
Author(s)
David Germack, Calvin Chan, Behrang Hamadani, Lee J. Richter, Daniel A. Fischer, David J. Gundlach, Dean DeLongchamp
The buried interface composition of polymer-fullerene blends is found by near edge X ray absorption fine structure (NEXAFS) spectroscopy to depend on the surface energy of the substrate upon which they are cast. The interface composition determines the

Controlling the Formation and Orientation of Terraced Nanoscale Ribbons of a Thiophene-Based Copolymer

March 24, 2009
Author(s)
Dean M. DeLongchamp, Regis J. Kline, Youngsuk Jung, David Germack, Eric K. Lin, Andrew Moad, Lee J. Richter, Michael F. Toney, Martin Heeney, Iain McCulloch
Terraced nanoscale ribbon domains of a poly(2,5-bis(3-alkylthiophen-2-yl) thieno[3,2-b]thiophene) form after thin films are cooled from its highest-temperature phase. A simple flow coating procedure can induce high levels of ribbon orientation and even

Semiconducting Thienothiophene Copolymers: Design, Synthesis, Morphology and Performance in Thin Film Organic Transistors

March 1, 2009
Author(s)
Iain McCulloch, Martin Heeney, Michael L. Chabinyc, Dean DeLongchamp, Regis J. Kline, Michael Colle, Warren Duffy, Daniel A. Fischer, David J. Gundlach, Behrang Hamadani, Rick Hamilton, Lee J. Richter, Alberto Salleo, Martin Shkunov, David Sparrowe, Steve Tierney, Weimin Zhang
Organic semiconductors are emerging as a viable alternative to amorphous silicon in a range of thin film transistor devices. , With the possibility to formulate these p-type materials as inks and subsequently print into patterned devices, organic based

The molecular basis of mesophase ordering in a thiophene-based copolymer

February 18, 2009
Author(s)
Dean M. DeLongchamp, Regis J. Kline, Youngsuk Jung, Eric K. Lin, Daniel A. Fischer, David J. Gundlach, Andrew Moad, Lee J. Richter, Michael F. Toney, Martin Heeney, Iain McCulloch
The carrier mobility of poly(2,5-bis(3-alkylthiophen-2-yl) thieno[3,2-b]thiophene) semiconductors can be substantially enhanced after heating through a thermotropic mesophase transition, which causes a significant improvement in thin film structural order

The Impact of the Dielectric / Semiconductor Interface on Microstructure and Charge Carrier Transport in High-Performance Polythiophene Transistors

May 14, 2008
Author(s)
Youngsuk Jung, Regis J. Kline, Eric K. Lin, Daniel A. Fischer, Michael F. Toney, Martin Heeney, Iain McCulloch, Dean DeLongchamp
The performance of organic field-effect transistors (OFETs) significantly depends on the properties of the interface between the semiconductor and gate dielectric. Here, we study the impact of chemically modified and morphologically controlled dielectrics

Microstructure of oligofluorene asymmetric derivatives in organic thin film transistors

April 22, 2008
Author(s)
Quan Yuan, Stefan C. Mannsfeld, Ming L. Tang, Mark Roberts, Michael F. Toney, Dean DeLongchamp, Zhenan Bao
In organic thin film transistors (OTFT), modifying the molecular chemical structure affects the molecular packing and thin film morphology, which both sensitively influence the charge carrier mobility. A detailed understanding of the interplay of molecular

The Effect of Interfacial Roughness on the Thin Film Morphology and Charge Transport of High-Performance Polythiophenes

March 11, 2008
Author(s)
Y S. Jung, Regis J. Kline, Daniel A. Fischer, Eric K. Lin, Martin Heeney, Iain McCulloch, Dean DeLongchamp
We control and vary the roughness of a dielectric upon which a high-performance polymer semiconductor, poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (pBTTT) is cast, to determine the effects of roughness on thin-film microstructure and the

Critical Role of Side-Chain Attachment Density on the Order and Device Performance of Polythiophenes

October 30, 2007
Author(s)
Regis J. Kline, Dean DeLongchamp, Daniel A. Fischer, Eric K. Lin, Lee J. Richter, Michael L. Chabinyc, Martin Heeney, Iain McCulloch
High performance, solution processable semiconductors are critical to the realization of low cost, large area electronics. We show that a signature molecular packing motif - side-chain interdigitation - correlates to high performance for a large and

High Carrier Mobility Polythiophene Thin Films: Structure Determination by Experiment and Theory

March 19, 2007
Author(s)
Dean M. DeLongchamp, Regis J. Kline, Eric K. Lin, Daniel A. Fischer, Lee J. Richter, Leah A. Lucas, Martin Heeney, Iain McCulloch, John E. Northrup
We exploit the unprecedented crystallinity of poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophenes) (pBTTTs) high performance semiconducting polymers to study structural detail within 25 nm thick films of a pBTTT with tetradecyl side chains (pBTTT

Controlling Diffusion and Exchange in Layer-by-Layer Assemblies

March 6, 2007
Author(s)
Nicole Zacharia, Dean DeLongchamp, Miguel Modestino, P T. Hammond
Here we present a layer-by-layer (LbL) assembled device architecture that serves as a model heterostructure to study the atypical assembly that can result from the bottom-up combination of multiple multilayers of different compositions. Heterostructure

Measuring Molecular Order in Poly(3-alkylthiophene) Thin Films with Polarizing Spectroscopies

January 16, 2007
Author(s)
Marc Gurau, Dean DeLongchamp, Brandon M. Vogel, Eric K. Lin, Daniel A. Fischer, S Sambasivan, Lee J. Richter
We measured the molecular order of poly(3-alkylthiophene) chains in thin films before and after melting through the combination of several polarized photon spectroscopies: infrared (IR) absorption, variable angle spectroscopic ellipsometry (SE), and near

Combinatorial screening of the effect of temperature on the microstructure and mobility of a high performance polythiophene semiconductor

January 1, 2007
Author(s)
Leah A. Lucas, Dean M. DeLongchamp, Brandon M. Vogel, Eric K. Lin, Michael J. Fasolka, Daniel A. Fischer, Iain McCulloch, Martin Heeney, Ghassan Jabbour
Using a gradient combinatorial approach, the authors report the effects of temperature on the microstructure and hole mobility of poly2,5-bis3-dodecylthiophen-2ylthieno3,2-bthiophene thin films for application in organic field-effect transistors. The