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Search Publications by: Lee J Richter (Fed)

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Displaying 1 - 25 of 300

Correlation of Structure and Morphology in an Ethylene-glycol Side-chain Modified Polythiophene via Combined X-ray Scattering and Four-dimensional Scanning Transmission Electron Microscopy

October 10, 2024
Author(s)
Andrew Herzing, Lucas Flagg, Chad R. Snyder, Lee Richter, Jonathan Onorato, Christine Luscombe, Ruipeng Li
We report the results of a combined grazing incidence wide-angle X-ray scattering (GIWAXS) and four-dimensional scanning transmission microscopy (4D-STEM) analysis of the effects of thermal processing on poly(3[2-(2-methoxyethoxy)ethoxy]-methylthiophene- 2

Salts as additives: A route to improve performance and stability of n-type organic electrochemical transistors

March 9, 2023
Author(s)
David Ohayon, Lucas Flagg, Andrea Giugni, Shofarul Wustoni, Ruipeng Li, Tania Hidalgo, Abdul Hamid Emwas, Rajendar Sheelamanthula, Iain McCulloch, Lee J. Richter, Sahika Inal
Organic electrochemical transistors (OECTs) are becoming increasingly ubiquitous in a wide variety of applications at the interface with biological systems, including biosensing, neuromorphic computing, and logic circuits. The widespread use of these

Certification of Standard Reference Material(R) 2196 Axial Resolution Standard for Optical Medical Imaging

February 7, 2023
Author(s)
Jeeseong C. Hwang, Kimberly Briggman, Nikki Rentz, Hyun-Jin Kim, David W. Allen, Lee J. Richter, Sowon Yoon, John Lu
Medical imaging devices and systems must be calibrated to ensure uniformity and reliability of test results. A standard reference material (SRM) or "phantom", as it is known in the medical imaging community, is used to replicate fundamental characteristics

Hydration of a side-chain-free n-type ladder semiconducting polymer driven by electrochemical doping

January 11, 2023
Author(s)
Jiajie Guo, Lucas Flagg, Duyen Tran, Shinya Chen, Ruipeng Li, Nagesh Kolhe, Rajiv Giridharagopal, Samson A. Jenekhe, Lee J. Richter, David Ginger
We study the organic electrochemical transistor (OECTs) performance of the ladder polymer, poly(benzimidazobenzophenanthroline) (BBL) in an attempt to better understand how an apparently insoluble side-chain free polymer is able to operate as an OECT with

All-Printed Ultrahigh-Responsivity MoS2 Nanosheet Photodetectors Enabled by Megasonic Exfoliation

July 5, 2022
Author(s)
Lee J. Richter, Lidia Kuo, Vinod Sangwan, Sonal Rangnekar, Ting-Ching Chu, David Lam, Shehao Zhu, Ruipeng Li, Julia Downing, Benjamin Luijten, Lincoln Lauhon, Mark Hersam
Printed two-dimensional materials, derived from solution-processed inks, offer scalable and cost-effective routes to mechanically flexible optoelectronics. With micron-scale control and broad processing latitude, aerosol-jet printing (AJP) is of particular

Fast Near-Infrared Photodetection using III-V Colloidal Quantum Dots

June 29, 2022
Author(s)
Lee J. Richter, Bin Sun, Amin M. Najarian, Chao Zheng, Laxmi K. Sagar, Min-Jae Choi, Xiyan Li, Larissa Levina, Se-Woong Baek, Seungjin Lee, Ahmad R. Kirmani, Jehad Abed, Mengxia Liu, Peicheng Li, Oleksandr Voznyy, Zheng H. Lu, F. Pelayo G. de Arquer, Edward H. Sargent
Colloidal quantum dots (CQDs) are promising materials for IR light detection due to their tunable bandgap and their solution processing; however, to date, the time response of CQD IR photodiodes has been inferior to that provided by Si and InGaAs. We

In-situ studies of the swelling by electrolyte in the electrochemical doping of an ethylene glycol substituted polythiophene

June 13, 2022
Author(s)
Lee J. Richter, Lucas Flagg, Lauren Asselta, Nicholas D'Antona, Natalie Stingelin, Tommaso Nicolini, Jonathan Onorato, Christine Luscombe, Ruipeng Li
Organic mixed ionic electronic conductors (OMIECs) have the potential to enable diverse new technologies, ranging from biosensors to flexible energy storage devices and neuromorphic computing platforms. However, study of these materials in their operating

Impact of Varying Side Chain Structure on Organic Electrochemical Transistor Performance: A Series of Oligoethylene Glycol-substituted Polythiophenes

April 19, 2022
Author(s)
Shinya Chen, Lucas Flagg, Jonathan Onorato, Lee J. Richter, Christine Luscombe, David Ginger
We study the electrochemical doping/dedoping kinetics, and the organic electrochemical transistor (OECT) performance of a series polythiophene homopolymers with ethylene glycol units in their side chains using both kosmotropic and chaotropic anion

Enhanced Near-Field Raman Spectroscopy

October 12, 2021
Author(s)
C E. Dentinger, Stephan J. Stranick, Lee J. Richter, Richard R. Cavanagh
Near-field Raman spectroscopy can be used to obtain chemical specificity with the subwavelength spatial resolution of near-field scanning optical microscopy (NSOM). We report detailed measurements of near-field Raman spectra from a single crystal diamond

Side Chain Engineering Control of Mixed Conduction in Oligoethylene Glycol-Substituted Polythiophenes

August 31, 2021
Author(s)
Jonathan Onorato, Zhongyang Wang, Yangyang Sun, Christian Nowak, Ban Dong, Lucas Flagg, Ruipeng Li, Lee J. Richter, Fernando Escobedo, Paul Nealey, Shrayesh Patel, Christine Luscombe
A major limitation for polymeric mixed ionic/electronic conductors (MIECs) is the trade-off between ionic and electronic conductivity; changes made that improve one typically hinder the other. In order to address this fundamental problem, this work

Polarized X-ray scattering measures molecular orientation in polymer-grafted nanoparticles

August 12, 2021
Author(s)
Subhrangsu Mukherjee, Dean DeLongchamp, Eliot Gann, Daniel Sunday, Lee J. Richter, Jason Streit, Richard A. Vaia, Baskar Ganapathysubramanian, Kumar Saurabh, Adarsh Krishnamurthy
Polymer chains are attached to nanoparticle surfaces for many purposes, including altering solubility, influencing aggregation, dispersion, and even tailoring immune responses in drug delivery. The most unique structural motif of polymer-grafted