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Wu Q, Wang K, Simpson A, Hao Y, Wang J, Li D, Hong X. Electrode Effect on Ferroelectricity in Free-Standing Membranes of PbZr 0.2Ti 0.8O 3. ACS Nanosci Au 2023; 3:482-490. [PMID: 38144704 PMCID: PMC10740143 DOI: 10.1021/acsnanoscienceau.3c00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 09/30/2023] [Accepted: 10/02/2023] [Indexed: 12/26/2023]
Abstract
We report the effects of screening capacity, surface roughness, and interfacial epitaxy of the bottom electrodes on the polarization switching, domain wall (DW) roughness, and ferroelectric Curie temperature (TC) of PbZr0.2Ti0.8O3 (PZT)-based free-standing membranes. Singe crystalline 10-50 nm (001) PZT and PZT/La0.67Sr0.33MnO3 (LSMO) membranes are prepared on Au, correlated oxide LSMO, and two-dimensional (2D) semiconductor MoS2 base layers. Switching the polarization of PZT yields nonvolatile current modulation in the MoS2 channel at room temperature, with an on/off ratio of up to 2 × 105 and no apparent decay for more than 3 days. Piezoresponse force microscopy studies show that the coercive field Ec for the PZT membranes varies from 0.75 to 3.0 MV cm-1 on different base layers and exhibits strong polarization asymmetry. The PZT/LSMO membranes exhibit significantly smaller Ec, with the samples transferred on LSMO showing symmetric Ec of about -0.26/+0.28 MV cm-1, smaller than that of epitaxial PZT films. The DW roughness exponent ζ points to 2D random bond disorder dominated DW roughening (ζ = 0.31) at room temperature. Upon thermal quench at progressively higher temperatures, ζ values for PZT membranes on Au and LSMO approach the theoretical value for 1D random bond disorder (ζ = 2/3), while samples on MoS2 exhibits thermal roughening (ζ = 1/2). The PZT membranes on Au, LSMO, and MoS2 show TC of about 763 ± 12, 725 ± 25, and 588 ± 12 °C, respectively, well exceeding the bulk value. Our study reveals the complex interplay between the electrostatic and mechanical boundary conditions in determining ferroelectricity in free-standing PZT membranes, providing important material parameters for the functional design of PZT-based flexible nanoelectronics.
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Affiliation(s)
- Qiuchen Wu
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Kun Wang
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Alyssa Simpson
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Yifei Hao
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Jia Wang
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Dawei Li
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
| | - Xia Hong
- Department
of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska−Lincoln, Lincoln, Nebraska 68588-0299, United
States
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Chatterjee S, Zamani E, Farzin S, Evazzade I, Obewhere OA, Johnson TJ, Alexandrov V, Dishari SK. Molecular-Level Control over Ionic Conduction and Ionic Current Direction by Designing Macrocycle-Based Ionomers. JACS Au 2022; 2:1144-1159. [PMID: 35647599 PMCID: PMC9131371 DOI: 10.1021/jacsau.2c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/22/2022] [Accepted: 04/28/2022] [Indexed: 06/15/2023]
Abstract
Poor ionic conductivity of the catalyst-binding, sub-micrometer-thick ionomer layers in energy conversion and storage devices is a huge challenge. However, ionomers are rarely designed keeping in mind the specific issues associated with nanoconfinement. Here, we designed nature-inspired ionomers (calix-2) having hollow, macrocyclic, calix[4]arene-based repeat units with precise, sub-nanometer diameter. In ≤100 nm-thick films, the in-plane proton conductivity of calix-2 was up to 8 times higher than the current benchmark ionomer Nafion at 85% relative humidity (RH), while it was 1-2 orders of magnitude higher than Nafion at 20-25% RH. Confocal laser scanning microscopy and other synthetic techniques allowed us to demonstrate the role of macrocyclic cavities in boosting the proton conductivity. The systematic self-assembly of calix-2 chains into ellipsoids in thin films was evidenced from atomic force microscopy and grazing incidence small-angle X-ray scattering measurements. Moreover, the likelihood of alignment and stacking of macrocyclic units, the presence of one-dimensional water wires across this macrocycle stacks, and thus the formation of long-range proton conduction pathways were suggested by atomistic simulations. We not only did see an unprecedented improvement in thin-film proton conductivity but also saw an improvement in proton conductivity of bulk membranes when calix-2 was added to the Nafion matrices. Nafion-calix-2 composite membranes also took advantage of the asymmetric charge distribution across calix[4]arene repeat units collectively and exhibited voltage-gating behavior. The inclusion of molecular macrocyclic cavities into the ionomer chemical structure can thus emerge as a promising design concept for highly efficient ion-conducting and ion-permselective materials for sustainable energy applications.
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Gao Y, Liu Y, Jiang J, Zhu C, Zuhlke C, Alexander D, Francisco JS, Zeng XC. Multiple Wetting-Dewetting States of a Water Droplet on Dual-Scale Hierarchical Structured Surfaces. JACS Au 2021; 1:955-966. [PMID: 34467342 PMCID: PMC8395622 DOI: 10.1021/jacsau.1c00183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Indexed: 06/12/2023]
Abstract
Surfaces with microscale roughness can entail dual-scale hierarchical structures such as the recently reported nano/microstructured surfaces produced in the laboratory (Wang et al. Nature2020, 582, 55-57). However, how the dual-scale hierarchical structured surface affects the apparent wetting/dewetting states of a water droplet, and the transitions between the states are still largely unexplored. Here, we report a systematic large-scale molecular dynamics (MD) simulation study on the wetting/dewetting states of water droplets on various dual-scale nano/near-submicrometer structured surfaces. To this end, we devise slab-water/slab-substrate model systems with a variety of dual-scale surface structures and with different degrees of intrinsic wettability (as measured based on the counterpart smooth surface). The dual-scale hierarchical structure can be described as "nanotexture-on-near-submicrometer-hill". Depending on three prototypical nanotextures, our MD simulations reveal five possible wetting/dewetting states for a water droplet: (i) Cassie state; (ii) infiltrated upper-valley state; (iii) immersed nanotexture-on-hill state; (iv) infiltrated valley state; and (v) Wenzel state. The transitions between these wetting/dewetting states are strongly dependent on the intrinsic wettability (E in), the initial location of the water droplet, the height of the nanotextures (H 1), and the spacing between nanotextures (W 1). Notably, E in-H 1 and E in-W 1 diagrams show that regions of rich wetting/dewetting states can be identified, including regions where between one to five states can coexist.
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Affiliation(s)
- Yurui Gao
- Department
of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States
- Laboratory
of Theoretical and Computational Nanoscience, National Center for Nanoscience and Technology, Chinese Academy of
Sciences, Beijing 100190, P. R. China
| | - Yuan Liu
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Jian Jiang
- Department
of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States
| | - Chongqin Zhu
- College
of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry
of Ministry of Education, Beijing Normal
University, Beijing 100875, P. R. China
- Department
of Earth and Environmental Science, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Craig Zuhlke
- Department
of Electrical and Computer Engineering, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States
| | - Dennis Alexander
- Department
of Electrical and Computer Engineering, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States
| | - Joseph S. Francisco
- Department
of Earth and Environmental Science, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Xiao Cheng Zeng
- Department
of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States
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Fan L, Constantin L, Wu ZP, McElveen KA, Chen XG, He T, Wang F, Debiemme-Chouvy C, Cui B, Lai RY, Li X, Silvain JF, Lu YF. Laser vibrational excitation of radicals to prevent crystallinity degradation caused by boron doping in diamond. Sci Adv 2021; 7:7/4/eabc7547. [PMID: 33523921 PMCID: PMC7817095 DOI: 10.1126/sciadv.abc7547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
Pursuing high-level doping without deteriorating crystallinity is prohibitively difficult but scientifically crucial to unleashing the hidden power of materials. This study demonstrates an effective route for maintaining lattice integrity during the combustion chemical vapor deposition of highly conductive boron-doped diamonds (BDDs) through laser vibrational excitation of a growth-critical radical, boron dihydride (BH2). The improved diamond crystallinity is attributed to a laser-enabled, thermal nonequilibrium suppression of the relative abundance of boron hydrides (BH), whose excessive presence induces boron segregation and disturbs the crystallization. The BDDs show a boron concentration of 4.3 × 1021 cm-3, a film resistivity of 28.1 milliohm·cm, and hole mobility of 55.6 cm2 V-1 s-1, outperforming a commercial BDD. The highly conductive and crystalline BDDs exhibit enhanced efficiency in sensing glucose, confirming the advantages of laser excitation in producing high-performance BDD sensors. Regaining crystallinity with laser excitation in doping process could remove the long-standing bottlenecks in semiconductor industry.
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Affiliation(s)
- L Fan
- Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - L Constantin
- Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
- The French National Centre for Scientific Research, CNRS, University of Bordeaux, Bordeaux INP, ICMCB UMR 5026, F-33608 Pessac, France
| | - Z P Wu
- Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - K A McElveen
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - X G Chen
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - T He
- Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - F Wang
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - C Debiemme-Chouvy
- Laboratoire Interfaces et Systémes Electrochimiques, UMR 8235, CNRS, Sorbonne Université, F-75252 Paris Cedex, France
| | - B Cui
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - R Y Lai
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - X Li
- Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - J F Silvain
- The French National Centre for Scientific Research, CNRS, University of Bordeaux, Bordeaux INP, ICMCB UMR 5026, F-33608 Pessac, France
| | - Y F Lu
- Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
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Allen JW, Tevatia R, Demirel Y, DiRusso CC, Black PN. Induction of oil accumulation by heat stress is metabolically distinct from N stress in the green microalgae Coccomyxa subellipsoidea C169. PLoS One 2018; 13:e0204505. [PMID: 30261009 PMCID: PMC6160078 DOI: 10.1371/journal.pone.0204505] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 09/10/2018] [Indexed: 11/25/2022] Open
Abstract
Algae are often promoted as feedstock organisms to produce a sustainable petroleum fossil fuel alternative. However, to induce lipid accumulation most often requires a severe stress that is difficult to induce in large batch cultures. The objective of this study is to analyze and mathematically model heat stress on growth, chlorophyll content, triacylglyceride, and starch synthesis in algae. We initially screened 30 algal species for the most pronounced induction of lipid droplets from heat stress using confocal microscopy and mass spectroscopy techniques. One species, Coccomyxa subellipsoidea C169, was selected and subjected to further biochemical analyses using a jacketed bioreactor amended with 1% CO2 at 25°C, 30°C, 32°C, 33°C, 34°C, 35°C, and 36°C. Lipid and starch accumulation was less extreme than N stress. Growth was reduced above 25°C, but heat stress induced lipid droplet synthesis was negatively correlated with growth only past a demonstrated threshold temperature above 32°C. The optimal temperature for lipid accumulation was 35°C, which led to 6% of dry weight triglyceride content and a 72% reduction from optimal growth after 5 days. Fatty acid influx rates into triglycerides and 15N labeling of amino acids and proteins indicate that heat stress is mechanistically distinct from N stress. Thus, this study lends support to a novel hypothesis that lipid droplet triglycerides result from a redistribution of carbon flux as fatty acids to neutral storage lipids over membrane or other lipids.
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Affiliation(s)
- James W. Allen
- Department of Biochemistry, Beadle Center, University of Nebraska-Lincoln, University of Nebraska-Lincoln, Lincoln, NE, United States of America
| | - Rahul Tevatia
- Department of Chemical and Biomolecular Engineering, Othmer Hall, University of Nebraska-Lincoln, Lincoln, NE, United States of America
| | - Yaşar Demirel
- Department of Chemical and Biomolecular Engineering, Othmer Hall, University of Nebraska-Lincoln, Lincoln, NE, United States of America
| | - Concetta C. DiRusso
- Department of Biochemistry, Beadle Center, University of Nebraska-Lincoln, University of Nebraska-Lincoln, Lincoln, NE, United States of America
| | - Paul N. Black
- Department of Biochemistry, Beadle Center, University of Nebraska-Lincoln, University of Nebraska-Lincoln, Lincoln, NE, United States of America
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