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Search Publications by: Behrang Hamadani (Fed)

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Displaying 51 - 70 of 70

Origin of Nanoscale Variations in Photoresponse of an Organic Solar Cell

April 22, 2010
Author(s)
Behrang H. Hamadani, Suyong S. Jung, Paul M. Haney, Lee J. Richter, Nikolai B. Zhitenev
Photo generated charge transport in bulk heterojunction (BHJ) solar cells is strongly dependent on the active layer nanomorphology resulting from phase segregation and connectivity of the donor and acceptor regions. Scanning probe-based techniques and in

Three-Dimensionally Structured Thin Film Heterojunction Photovoltaics on Interdigitated Back-Contacts

February 1, 2010
Author(s)
Daniel Josell, Carlos R. Beauchamp, Behrang H. Hamadani, Suyong S. Jung, Jonathan E. Guyer, Abhishek Motayed, Carlos M. Hangarter, Nadine E. Gergel-Hackett, Hua Xu, Nikolai B. Zhitenev
Fabrication and properties of three-dimensionally structured back-contact heterojunction solar cells are described. A variety of devices are explored, all of which were fabricated by electrochemical deposition of a semiconducting material on one of two

Flexible Memristors

December 3, 2009
Author(s)
Nadine E. Gergel-Hackett, Laurie A. Stephey, Barbara Dunlap, Behrang H. Hamadani, David J. Gundlach, Curt A. Richter

Flexible Memristors

December 3, 2009
Author(s)
Nadine Gergel-Hackett, Laurie Stephey, Barbara Dunlap, Behrang Hamadani, David J. Gundlach, Curt A. Richter

Nanoscale Photoresponse in Blended Organic Photovoltaics

August 16, 2009
Author(s)
Behrang H. Hamadani, Suyong S. Jung, Nikolai B. Zhitenev
Organic solar cells, which have attracted considerable interest over the last few years as low-cost, simply-processed alternatives for harvesting the solar energy, have interesting nanoscale properties; a thorough understanding of which is currently

Three-Dimensionally Structured CdTe Thin Film Photovoltaic Devices with Self-Aligned Back Contacts: Electrodeposition on Interdigitated Electrodes.

June 25, 2009
Author(s)
Daniel Josell, Carlos R. Beauchamp, Suyong S. Jung, Behrang H. Hamadani, Abhishek Motayed, Lee J. Richter, Maureen E. Williams, John E. Bonevich, Alexander J. Shapiro, Nikolai B. Zhitenev, Thomas P. Moffat
Cadmium-telluride photovoltaic cells were deposited on substrates patterned with two interdigitated electrodes. Deposition involved application of different potentials to the two electrodes in order to obtain a 3-d gradient of film properties within the

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

Flexible Solution-Processed Memristors

June 3, 2009
Author(s)
Nadine E. Gergel-Hackett, Behrang H. Hamadani, B Dunlap, John S. Suehle, Curt A. Richter, Christina A. Hacker, David J. Gundlach
We have fabricated physically flexible nonvolatile memory devices using inexpensive, room-temperature, solution processing. The behavior of these devices is consistent with that of a memristor device, the missing fourth circuit element theoretically

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

Surface Potential Imaging of Solution Processable Acene-Based Thin Film Transistors

December 2, 2008
Author(s)
Lucile C. Teague, Behrang H. Hamadani, John E. Anthony, David J. Gundlach, James G. Kushmerick, Sanker Subramanian, Thomas Jackson, Curt A. Richter, Oana Jurchescu
We report scanning Kelvin probe microscopy (SKPM) of electrically biased difluoro bis(triethylsilylethynyl) anthradithiophene (diF-TESADT) organic thin film transistors. SKPM reveals the relationship between the diF-TESADT film structure and device

High Performance Organic Thin-Film Transistors Made Simple Through Molecular Design and Processing

October 17, 2008
Author(s)
Oana Jurchescu, Marina Feric, Behrang H. Hamadani, M. Devin, Sankar Subramanian, Balaji Purushothamanc, John E. Anthony, Thomas Jackson, David J. Gundlach
We report on a simple a method of inducing self-isolation of the thin film transistors via manipulation of the chemical interactions between the organic molecules and the surfaces where they are deposited. We use pentafluorobenzenethiol (PFBT) treatment of

Correlation Between Microstructure, Electronic Properties and Ficker Noise in Organic Thin Film Transistors

March 31, 2008
Author(s)
Oana Jurchescu, Behrang H. Hamadani, Hao Xiong, Sungkyu Park, Sankar Subramanian, Neil M. Zimmerman, John E. Anthony, Thomas Jackson, David J. Gundlach
We report on observations of a direct correlation between the microstructure of the organic thin films and their electronic properties when incorporated in field-effect transistors. We present a simple method to induce enhanced grain growth in solution

Contact-induced crystallinity for high-performance soluble acene-based transistors and circuits

March 8, 2008
Author(s)
David J. Gundlach, James E. Royer, SK Park, Sankar Subramanian, Oana Jurchescu, Behrang H. Hamadani, Andrew Moad, Regis J. Kline, LC Teague, Oleg A. Kirillov, Curt A. Richter, Lee J. Richter, Sean R. Parkin, Thomas Jackson, JE Anthony
The use of organic materials presents a tremendous opportunity to significantly impact the functionality and pervasiveness of large-area electronics. Commercialization of this technology requires reduction in manufacturing costs by exploiting inexpensive

Contact Induced Crystallinity for High Performance Soluble Acene-Based TFTs

February 17, 2008
Author(s)
David J. Gundlach, James Royer, Behrang Hamadani, Lucile C. Teague, Andrew J. Moad, Oana Jurchescu, Oleg A. Kirillov, Lee J. Richter, James G. Kushmerick, Curt A. Richter, Sungkyu Park, Thomas Jackson, Sankar Subramanian, John E. Anthony
Organic electronics present a tremendous opportunity to significantly impact the functionality and pervasiveness of large-area electronics. However, the lack of low-temperature low-cost deposition and patterning techniques limits the potential for the

Undoped polythiophene FETs with field-effect mobility of 1 cm^2 V^-1 s^-1

December 29, 2007
Author(s)
Behrang Hamadani, Iain McCulloch, Martin Heeney, David J. Gundlach
We report on charge transport in organic field-effect transistors based on (2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) as the active polymer layer with saturation field-effect mobilities as large as 1 cm2 V-1 s-1. The dependence of mobility

Distinguishing Between Nonlinear Channel Transport and Contact Effects in Organic FETs

August 30, 2007
Author(s)
Behrang Hamadani, Jeremy LeBoeuf, R J. Kline, Iain McCulloch, Martin Heeney, Curt A. Richter, Lee J. Richter, David J. Gundlach
We investigate charge injection and transport in organic field-effect transistors fabricated by using poly(2,5-bis(3-tetradecylthiophene-2-yl)thieno[3,2-b]thiophene) (pBTTT-C14) as the active polymer layer. We show that in high mobility devices where the