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Wang Y, Ma R, Nie W, Zhao X, Yin J. Enhanced Electrorheological Performance of Core-Shell-Structured Polymerized Ionic Liquid@Doubly Polymerized Ionic Liquid Microspheres Prepared via Evaporation-Assisted Dispersion Polymerization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:14006-14014. [PMID: 37738145 DOI: 10.1021/acs.langmuir.3c01745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
A polymerized ionic liquid (PIL) provides a platform for the development of a high-performance water-free polyelectrolyte-based electrorheological fluid (ERF) because of the presence of large-size hydrophobic ion pairs. However, the large-size hydrophobic ion pairs also easily result in a low glass-transition temperature of an ordinary linear PIL, and consequently, the PIL-based ERF has to be subject to a high leaking current density and a narrow working temperature range. In this paper, we prepared a kind of core-shell-structured polymerized ionic liquid@doubly polymerized ionic liquid (PIL@D-PIL) microsphere with a linear PIL as the core and a physically cross-linked D-PIL as the shell via an evaporation-assisted dispersion polymerization method. The core-shell structure of the sample was observed by scanning electron microscopy and transmission electron microscopy. The thermal properties of the sample were tested by differential scanning calorimetery and thermogravimetric analysis. The ER effect and dielectric polarization of PIL@D-PIL microspheres when dispersed in an insulating nonpolar liquid were studied by a rheometer and dielectric spectroscopy. It shows that the glass-transition temperature and thermal stability of a PIL increased after coating with the D-PIL shell. Under electric fields, the ERF of the PIL@D-PIL microspheres exhibits a significantly reduced leaking current density and an enhanced operating temperature range compared to the ERF of single-PIL microspheres. The PIL@D-PIL microspheres can still maintain good ER effect even if the temperature is higher than the glass-transition point of the PIL core due to the protection of the D-PIL shell.
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Affiliation(s)
- Yudong Wang
- Smart Materials Laboratory, Department of Applied Physics, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, Shaanxi 710129, China
| | - Ruijing Ma
- Smart Materials Laboratory, Department of Applied Physics, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, Shaanxi 710129, China
| | - Wuyang Nie
- Smart Materials Laboratory, Department of Applied Physics, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, Shaanxi 710129, China
| | - Xiaopeng Zhao
- Smart Materials Laboratory, Department of Applied Physics, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, Shaanxi 710129, China
| | - Jianbo Yin
- Smart Materials Laboratory, Department of Applied Physics, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, Shaanxi 710129, China
- Shaanxi Basic Discipline (Liquid Physics) Research Center, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, Shaanxi 710129, China
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Affiliation(s)
- Swati Arora
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Julisa Rozon
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Jennifer E. Laaser
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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Liu M, Jaiswal HN, Shahi S, Wei S, Fu Y, Chang C, Chakravarty A, Liu X, Yang C, Liu Y, Lee YH, Perebeinos V, Yao F, Li H. Two-Dimensional Cold Electron Transport for Steep-Slope Transistors. ACS NANO 2021; 15:5762-5772. [PMID: 33705651 DOI: 10.1021/acsnano.1c01503] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Room-temperature Fermi-Dirac electron thermal excitation in conventional three-dimensional (3D) or two-dimensional (2D) semiconductors generates hot electrons with a relatively long thermal tail in energy distribution. These hot electrons set a fundamental obstacle known as the "Boltzmann tyranny" that limits the subthreshold swing (SS) and therefore the minimum power consumption of 3D and 2D field-effect transistors (FETs). Here, we investigated a graphene (Gr)-enabled cold electron injection where the Gr acts as the Dirac source to provide the cold electrons with a localized electron density distribution and a short thermal tail at room temperature. These cold electrons correspond to an electronic refrigeration effect with an effective electron temperature of ∼145 K in the monolayer MoS2, which enables the transport factor lowering and thus the steep-slope switching (across for three decades with a minimum SS of 29 mV/decade at room temperature) for a monolayer MoS2 FET. Especially, a record-high sub-60-mV/decade current density (over 1 μA/μm) can be achieved compared to conventional steep-slope technologies such as tunneling FETs or negative capacitance FETs using 2D or 3D channel materials. Our work demonstrates the potential of a 2D Dirac-source cold electron transistor as a steep-slope transistor concept for future energy-efficient nanoelectronics.
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Affiliation(s)
- Maomao Liu
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Hemendra Nath Jaiswal
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Simran Shahi
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Sichen Wei
- Department of Materials Design and Innovation, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Yu Fu
- Department of Materials Design and Innovation, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Chaoran Chang
- Department of Materials Design and Innovation, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Anindita Chakravarty
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Xiaochi Liu
- School of Physics and Electronics, Central South University, Changsha 410083, China
| | - Cheng Yang
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Yanpeng Liu
- Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Korea
| | - Vasili Perebeinos
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Fei Yao
- Department of Materials Design and Innovation, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Huamin Li
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
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Kelsheimer CJ, Garrett-Roe S. Intramolecular Vibrational Energy Relaxation of CO 2 in Cross-Linked Poly(ethylene glycol) Diacrylate-Based Ion Gels. J Phys Chem B 2021; 125:1402-1415. [PMID: 32955891 DOI: 10.1021/acs.jpcb.0c06685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultrafast two-dimensional infrared spectroscopy (2D-IR) and Fourier transform infrared spectroscopy (FTIR) were used to measure carbon dioxide (CO2) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]), cross-linked low-molecular-weight poly(ethylene glycol) diacrylate (PEGDA), and an ion gel composed of a 50 vol % blend of the two. The center frequency of the antisymmetric stretch, ν3, of CO2 shifts monotonically to lower wavenumbers with increasing polymer content, with the largest line width in the ion gel (6 cm-1). Increasing polymer content slows both spectral diffusion and vibrational energy relaxation (VER) rates. An unexpected excited-state absorbance peak appears in the 2D-IR of cross-linked PEGDA due to VER from the antisymmetric stretch into the bending mode, ν2. Thirty-two response functions are necessary to describe the observed features in the 2D-IR spectra. Nonlinear least-squares fitting extracts both spectral diffusion and VER rates. In the ion gel, CO2 exhibits spectral diffusion dynamics that lie between that of the pure compounds. The kinetics of VER reflect both fast excitation and de-excitation of the bending mode, similar to the ionic liquid (IL), and slow overall vibrational population relaxation, similar to the cross-linked polymer. The IL-like and polymer-like dynamics suggest that the CO2 resides at the interface of the two components in the ion gel.
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Affiliation(s)
- C J Kelsheimer
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Sean Garrett-Roe
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
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Fathipour S, Paletti P, Fullerton-Shirey SK, Seabaugh AC. Electric-double-layer p-i-n junctions in WSe 2. Sci Rep 2020; 10:12890. [PMID: 32732940 PMCID: PMC7393156 DOI: 10.1038/s41598-020-69523-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/10/2020] [Indexed: 12/01/2022] Open
Abstract
While p-n homojunctions in two-dimensional transition metal dichalcogenide materials have been widely reported, few show an ideality factor that is constant over more than a decade in current. In this paper, electric double layer p-i-n junctions in WSe2 are shown with substantially constant ideality factors (2-3) over more than 3 orders of magnitude in current. These lateral junctions use the solid polymer, polyethylene oxide: cesium perchlorate (PEO:CsClO4), to induce degenerate electron and hole carrier densities at the device contacts to form the junction. These high carrier densities aid in reducing the contact resistance and enable the exponential current dependence on voltage to be measured at higher currents than prior reports. Transport measurements of these WSe2 p-i-n homojunctions in combination with COMSOL multiphysics simulations are used to quantify the ion distributions, the semiconductor charge distributions, and the simulated band diagram of these junctions, to allow applications to be more clearly considered.
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Affiliation(s)
- Sara Fathipour
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Paolo Paletti
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Susan K Fullerton-Shirey
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Alan C Seabaugh
- Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA.
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