1
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Faubel RJ, Santos Canellas VS, Gaesser J, Beluk NH, Feinstein TN, Wang Y, Yankova M, Karunakaran KB, King SM, Ganapathiraju MK, Lo CW. Flow blockage disrupts cilia-driven fluid transport in the epileptic brain. Acta Neuropathol 2022; 144:691-706. [PMID: 35980457 DOI: 10.1007/s00401-022-02463-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 01/28/2023]
Abstract
A carpet of ependymal motile cilia lines the brain ventricular system, forming a network of flow channels and barriers that pattern cerebrospinal fluid (CSF) flow at the surface. This CSF transport system is evolutionary conserved, but its physiological function remains unknown. Here we investigated its potential role in epilepsy with studies focused on CDKL5 deficiency disorder (CDD), a neurodevelopmental disorder with early-onset epilepsy refractory to seizure medications and the most common cause of infant epilepsy. CDKL5 is a highly conserved X-linked gene suggesting its function in regulating cilia length and motion in the green alga Chlamydomonas might have implication in the etiology of CDD. Examination of the structure and function of airway motile cilia revealed both the CDD patients and the Cdkl5 knockout mice exhibit cilia lengthening and abnormal cilia motion. Similar defects were observed for brain ventricular cilia in the Cdkl5 knockout mice. Mapping ependymal cilia generated flow in the ventral third ventricle (v3V), a brain region with important physiological functions showed altered patterning of flow. Tracing of cilia-mediated inflow into v3V with fluorescent dye revealed the appearance of a flow barrier at the inlet of v3V in Cdkl5 knockout mice. Analysis of mice with a mutation in another epilepsy-associated kinase, Yes1, showed the same disturbance of cilia motion and flow patterning. The flow barrier was also observed in the Foxj1± and FOXJ1CreERT:Cdkl5y/fl mice, confirming the contribution of ventricular cilia to the flow disturbances. Importantly, mice exhibiting altered cilia-driven flow also showed increased susceptibility to anesthesia-induced seizure-like activity. The cilia-driven flow disturbance arises from altered cilia beating orientation with the disrupted polarity of the cilia anchoring rootlet meshwork. Together these findings indicate motile cilia disturbances have an essential role in CDD-associated seizures and beyond, suggesting cilia regulating kinases may be a therapeutic target for medication-resistant epilepsy.
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Affiliation(s)
- Regina J Faubel
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15201, USA
| | - Veronica S Santos Canellas
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15201, USA
| | - Jenna Gaesser
- Division of Child Neurology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15201, USA
| | - Nancy H Beluk
- Division of Radiology, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Tim N Feinstein
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15201, USA
| | - Yong Wang
- Laboratory for Fluid Physics, Pattern Formation and Biocomplexity, Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, 37077, Göttingen, Germany
| | - Maya Yankova
- Department of Molecular Biology and Biophysics, And Electron Microscopy Facility, University of Connecticut Health Center, Farmington, CT, 06030-3305, USA
| | - Kalyani B Karunakaran
- Supercomputer Education and Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Stephen M King
- Department of Molecular Biology and Biophysics, And Electron Microscopy Facility, University of Connecticut Health Center, Farmington, CT, 06030-3305, USA
| | - Madhavi K Ganapathiraju
- Department of Biomedical Informatics, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15201, USA
| | - Cecilia W Lo
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15201, USA.
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2
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Han E, Fang W, Stamatakis M, Richardson JO, Chen J. Quantum Tunnelling Driven H 2 Formation on Graphene. J Phys Chem Lett 2022; 13:3173-3181. [PMID: 35362977 DOI: 10.1021/acs.jpclett.2c00520] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
It is commonly believed that it is unfavorable for adsorbed H atoms on carbonaceous surfaces to form H2 without the help of incident H atoms. Using ring-polymer instanton theory to describe multidimensional tunnelling effects, combined with ab initio electronic structure calculations, we find that these quantum-mechanical simulations reveal a qualitatively different picture. Recombination of adsorbed H atoms, which was believed to be irrelevant at low temperature due to high barriers, is enabled by deep tunnelling, with reaction rates enhanced by tens of orders of magnitude. Furthermore, we identify a new path for H recombination that proceeds via multidimensional tunnelling but would have been predicted to be unfeasible by a simple one-dimensional description of the reaction. The results suggest that hydrogen molecule formation at low temperatures are rather fast processes that should not be ignored in experimental settings and natural environments with graphene, graphite, and other planar carbon segments.
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Affiliation(s)
- Erxun Han
- School of Physics, Peking University, Beijing 100871, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, People's Republic of China
| | - Wei Fang
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
- Department of Chemistry, Fudan University, Shanghai 200438, China
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Michail Stamatakis
- Thomas Young Centre and Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
| | | | - Ji Chen
- School of Physics, Peking University, Beijing 100871, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing 100871, People's Republic of China
- Frontiers Science Center for Nano-Optoelectronics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
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3
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Lee S, Min B, Bang J. Substrate effect on hydrogen evolution reaction in two-dimensional Mo 2C monolayers. Sci Rep 2022; 12:6076. [PMID: 35414153 PMCID: PMC9005693 DOI: 10.1038/s41598-022-09935-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/29/2022] [Indexed: 11/11/2022] Open
Abstract
The physical and chemical properties of atomically thin two-dimensional (2D) materials can be modified by the substrates. In this study, the substrate effect on the electrocatalytic hydrogen evolution reaction (HER) in 2D Mo2C monolayers was investigated using first principles calculations. The isolated Mo2C monolayer shows large variation in HER activity depending on hydrogen coverage: it has relatively low activity at low hydrogen coverage but high activity at high hydrogen coverage. Among Ag, Au, Cu, and graphene substrates, the HER activity is improved on the Ag and Cu substrates especially at low hydrogen coverage, while the effects of the Au and graphene substrates on the HER activity are insignificant. The improvement is caused by the charge redistribution in the Mo2C layer on the substrate, and therefore the HER activity becomes high for any hydrogen coverage on the Ag and Cu substrates. Our results suggest that, in two-dimensional electrocatalysis, the substrate has a degree of freedom to tune the catalytic activity.
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Affiliation(s)
- Sujin Lee
- Department of Energy and Materials Engineering, Dongguk University-Seoul, Seoul, 04620, Korea
| | - Byungjoon Min
- Department of Physics, Chungbuk National University, Cheongju, 28644, Republic of Korea.,Research Institute for Nanoscale Science and Technology, Cheongju, 28644, Republic of Korea
| | - Junhyeok Bang
- Department of Physics, Chungbuk National University, Cheongju, 28644, Republic of Korea. .,Research Institute for Nanoscale Science and Technology, Cheongju, 28644, Republic of Korea.
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4
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Delayed Implantation Induced by Letrozole in Mice. Reprod Sci 2022; 29:2864-2875. [PMID: 35257352 DOI: 10.1007/s43032-022-00902-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 02/23/2022] [Indexed: 11/27/2022]
Abstract
Implantation timing is critical for a successful pregnancy. A short delay in embryo implantation caused by targeted gene ablation produced a cascading problem in the later stages of the pregnancy. Although several delayed implantation models have been established in wild mice, almost none of them is suitable for investigating the early delay's effects on the late events of pregnancy. Here, we report a new delayed implantation model established by the intraperitoneal administration of letrozole at 5 mg/kg body weight on day 3 of pregnancy. In these mice, initiation of implantation was induced at will by the injection of estradiol (E2). When the estradiol (3 ng) was injected on day 4 of pregnancy (i.e., without delay), the embryo implantation restarted, and the pregnancy continued normally. However, 25 ng estrogen caused compromised implantation. We also found that 67% of the female mice could be pregnant normally and finally gave birth when the estradiol injection (3 ng) was on day 5 of pregnancy (i.e., 1-day delay). Most failed pregnancies had impaired decidualization, decreased serum progesterone levels, and compromised angiogenesis. Progesterone supplementation could rescue decidualization failure in the mice. Collectively, we established a new model of delayed implantation by letrozole, which can be easily applied to study the effect and mechanisms of delay of embryo implantation on the progression of late pregnancy events.
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5
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Linker T, Tiwari S, Fukushima S, Kalia RK, Krishnamoorthy A, Nakano A, Nomura KI, Shimamura K, Shimojo F, Vashishta P. Optically Induced Three-Stage Picosecond Amorphization in Low-Temperature SrTiO 3. J Phys Chem Lett 2020; 11:9605-9612. [PMID: 33124829 DOI: 10.1021/acs.jpclett.0c02873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photoexcitation can drastically modify potential energy surfaces of materials, allowing access to hidden phases. SrTiO3 (STO) is an ideal material for photoexcitation studies due to its prevalent use in nanostructured devices and its rich range of functionality-changing lattice motions. Recently, a hidden ferroelectric phase in STO was accessed through weak terahertz excitation of polarization-inducing phonon modes. In contrast, whereas strong laser excitation was shown to induce nanostructures on STO surfaces and control nanopolarization patterns in STO-based heterostructures, the dynamic pathways underlying these optically induced structural changes remain unknown. Here nonadiabatic quantum molecular dynamics reveals picosecond amorphization in photoexcited STO at temperatures as low as 10 K. The three-stage pathway involves photoinduced charge transfer and optical phonon activation followed by nonlinear charge and lattice dynamics that ultimately lead to amorphization. This atomistic understanding could guide not only rational laser nanostructuring of STO but also broader "quantum materials on demand" technologies.
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Affiliation(s)
- Thomas Linker
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Subodh Tiwari
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Shogo Fukushima
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Rajiv K Kalia
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Aravind Krishnamoorthy
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Aiichiro Nakano
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Ken-Ichi Nomura
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Kohei Shimamura
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Fuyuki Shimojo
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Priya Vashishta
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
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6
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Cheng K, Wang H, Bang J, West D, Zhao J, Zhang S. Carrier Dynamics and Transfer across the CdS/MoS 2 Interface upon Optical Excitation. J Phys Chem Lett 2020; 11:6544-6550. [PMID: 32693591 DOI: 10.1021/acs.jpclett.0c01188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Carrier dynamics across the interface of heterostructures have important technological, photovoltaic, and catalytic implications. Using first-principles time-dependent density functional theory, we have systematically investigated the charge transfer of excited carriers from CdS to MoS2 and found that two interdependent mechanisms are responsible for the transfer, one slow and one fast. While the slower process may be attributed to typical electron-phonon coupling, the interfacial dipole resulting from this transfer enables a fast secondary process involving a level crossing of the excited carrier state in CdS with receiving states in MoS2. An analysis based on the interfacial binding energy reveals that the Cd-terminated (001) interface is by far the most energetically favorable, which in addition to its calculated fast resonant electron transfer suggests it is a good candidate to explain the experimentally observed charge transfer between CdS and MoS2.
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Affiliation(s)
- Kai Cheng
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China
| | - Han Wang
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Junhyeok Bang
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Department of Physics, Chungbuk National University, Chungbuk 28644, Republic of Korea
| | - Damien West
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Jijun Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China
| | - Shengbai Zhang
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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7
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Si C, Choe D, Xie W, Wang H, Sun Z, Bang J, Zhang S. Photoinduced Vacancy Ordering and Phase Transition in MoTe 2. NANO LETTERS 2019; 19:3612-3617. [PMID: 31096752 DOI: 10.1021/acs.nanolett.9b00613] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We show that non-equilibrium dynamics plays a central role in the photoinduced 2H-to-1T' phase transition of MoTe2. The phase transition is initiated by a local ordering of Te vacancies, followed by a 1T' structural change in the original 2H lattice. The local 1T' region serves as a seed to gather more vacancies into ordering and subsequently induces a further growth of the 1T' phase. Remarkably, this process is controlled by photogenerated excited carriers as they enhance vacancy diffusion, increase the speed of vacancy ordering, and are hence vital to the 1T' phase transition. This mechanism can be contrasted to the current model requiring a collective sliding of a whole Te atomic layer, which is thermodynamically highly unlikely. By uncovering the key roles of photoexcitations, our results may have important implications for finely controlling phase transitions in transition metal dichalcogenides.
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Affiliation(s)
- Chen Si
- School of Materials Science and Engineering , Beihang University , Beijing 100191 , People's Republic of China
- Department of Physics, Applied Physics, & Astronomy , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Dukhyun Choe
- Department of Physics, Applied Physics, & Astronomy , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Weiyu Xie
- Department of Physics, Applied Physics, & Astronomy , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Han Wang
- Department of Physics, Applied Physics, & Astronomy , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Zhimei Sun
- School of Materials Science and Engineering , Beihang University , Beijing 100191 , People's Republic of China
| | - Junhyeok Bang
- Spin Engineering Physics Team , Korea Basic Science Institute (KBSI) , Daejeon 305-806 , Republic of Korea
| | - Shengbai Zhang
- Department of Physics, Applied Physics, & Astronomy , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
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8
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Cho J, Sheng A, Suwandaratne N, Wangoh L, Andrews JL, Zhang P, Piper LFJ, Watson DF, Banerjee S. The Middle Road Less Taken: Electronic-Structure-Inspired Design of Hybrid Photocatalytic Platforms for Solar Fuel Generation. Acc Chem Res 2019; 52:645-655. [PMID: 30543407 DOI: 10.1021/acs.accounts.8b00378] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The development of efficient solar energy conversion to augment other renewable energy approaches is one of the grand challenges of our time. Water splitting, or the disproportionation of H2O into energy-dense fuels, H2 and O2, is undoubtedly a promising strategy. Solar water splitting involves the concerted transfer of four electrons and four protons, which requires the synergistic operation of solar light harvesting, charge separation, mass and charge transport, and redox catalysis processes. It is unlikely that individual materials can mediate the entire sequence of charge and mass transport as well as energy conversion processes necessary for photocatalytic water splitting. An alternative approach, emulating the functioning of photosynthetic systems, involves the utilization of hybrid systems wherein different components perform the various functions required for solar water splitting. The design of such hybrid systems requires the multiple components to operate in lockstep with optimal thermodynamic driving forces and interfacial charge transfer kinetics. This Account describes a new class of nanoscale heterostructures comprising M xV2O5 nanowires, where M is a p-block cation with a ( n - 1) d10 ns2 np0 electronic configuration characterized by a stereoactive lone pair of electrons and x is its stoichiometry, interfaced with II-VI semiconductor quantum dots (QDs). Photocatalytic water splitting involves the transfer of excited-state holes from QDs to mid-gap states (derived from the stereoactive lone pairs of p-block cations) of nanowires, hole transport through nanowires, the reduction of protons at a QD-immobilized catalyst, and water oxidation at an anode. The M xV2O5/QD architectures provide a vast design space for evolutionary optimization of function with considerable tunability of composition and structure of the individual components as well as of the interfacial structure, thereby facilitating programmability of absorption spectra, energetic offsets, and charge-transfer reactivity. The available design space spans choice of the p-block cation M, its stoichiometry x, the composition and size of various QDs, and the nature of the nanowire/QD interface. This multivariate parameter space has been navigated by integrating first-principles modeling, diversified synthesis, spectroscopic measurements, and catalytic evaluation to facilitate the rational design of several generations of heterostructures and the systematic improvement of their photocatalytic performance. The electronic structures of the target heterostructures are predicted by DFT calculations in light of the revised lone pair model of stereoactive structural distortions and evaluated by hard X-ray photoelectron spectroscopy such as to systematically tune the interfacial band offsets. Central to this approach is the development of a topochemical "etch-a-sketch" intercalation approach that allows for facile installation of p-block cations in metastable polymorphs of V2O5. The interfacial charge transfer kinetics of M xV2O5/QD heterostructures is further evaluated by transient absorption spectroscopy to measure excited-state charge-transfer dynamics and is found to depend sensitively on interfacial structure and the thermodynamic driving forces in accordance with Marcus theory. The integration of theory and experiment has allowed for the design of viable photocatalytic architectures exemplified by the exceptional catalytic performance of β-Pb xV2O5/CdX (X= S, Se) architectures, which has subsequently been elaborated to other lone-pair M xV2O5 compounds, demonstrating the effective exploitation of the opportunities for programmability available in the design space.
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Affiliation(s)
- Junsang Cho
- Departments of Chemistry and Materials Science and Engineering, Texas A&M University, College Station, Texas 77842-3012, United States
| | - Aaron Sheng
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Nuwanthi Suwandaratne
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Linda Wangoh
- Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902, United States
| | - Justin L. Andrews
- Departments of Chemistry and Materials Science and Engineering, Texas A&M University, College Station, Texas 77842-3012, United States
| | - Peihong Zhang
- Department of Physics, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Louis F. J. Piper
- Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902, United States
| | - David F. Watson
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States
| | - Sarbajit Banerjee
- Departments of Chemistry and Materials Science and Engineering, Texas A&M University, College Station, Texas 77842-3012, United States
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9
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Kumazoe H, Krishnamoorthy A, Bassman L, Kalia RK, Nakano A, Shimojo F, Vashishta P. Photo-induced lattice contraction in layered materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:32LT02. [PMID: 29957601 DOI: 10.1088/1361-648x/aad022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Structural and electronic changes induced by optical excitation is a promising technique for functionalization of 2D crystals. Characterizing the effect of excited electronic states on the in-plane covalent bonding network as well as the relatively weaker out-of-plane dispersion interactions is necessary to tune photo-response in these highly anisotropic crystal structures. In-plane atom dynamics was measured using pump-probe experiments and characterized using ab initio simulations, but the effect of electronic excitation on weak out-of-plane van der Waals bonds is less well-studied. We use non-adiabatic quantum molecular dynamics to investigate atomic motion in photoexcited MoS2 bilayers. We observe a strong athermal reduction in the lattice parameter along the out-of-plane direction within 100 fs after electronic excitation, resulting from redistribution of electrons to excited states that have lesser anti-bonding character between layers. This non-trivial behavior of weakly bonded interactions during photoexcitation could have potential applications for modulating properties in materials systems containing non-covalent interactions like layered materials and polymers.
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Affiliation(s)
- Hiroyuki Kumazoe
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
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10
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Bassman L, Krishnamoorthy A, Kumazoe H, Misawa M, Shimojo F, Kalia RK, Nakano A, Vashishta P. Electronic Origin of Optically-Induced Sub-Picosecond Lattice Dynamics in MoSe 2 Monolayer. NANO LETTERS 2018; 18:4653-4658. [PMID: 29990437 DOI: 10.1021/acs.nanolett.8b00474] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Atomically thin layers of transition metal dichalcogenide (TMDC) semiconductors exhibit outstanding electronic and optical properties, with numerous applications such as valleytronics. While unusually rapid and efficient transfer of photoexcitation energy to atomic vibrations was found in recent experiments, its electronic origin remains unknown. Here, we study the lattice dynamics induced by electronic excitation in a model TMDC monolayer, MoSe2, using nonadiabatic quantum molecular dynamics simulations. Simulation results show sub-picosecond disordering of the lattice upon photoexcitation, as measured by the Debye-Waller factor, as well as increasing disorder for higher densities of photogenerated electron-hole pairs. Detailed analysis shows that the rapid, photoinduced lattice dynamics are due to phonon-mode softening, which in turn arises from electronic Fermi surface nesting. Such mechanistic understanding can help guide optical control of material properties for functionalizing TMDC layers, enabling emerging applications such as phase change memories and neuromorphic computing.
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Affiliation(s)
| | | | - Hiroyuki Kumazoe
- Department of Physics , Kumamoto University , Kumamoto 860-8555 , Japan
| | - Masaaki Misawa
- Department of Physics , Kumamoto University , Kumamoto 860-8555 , Japan
| | - Fuyuki Shimojo
- Department of Physics , Kumamoto University , Kumamoto 860-8555 , Japan
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11
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Krishnamoorthy A, Bassman Oftelie L, Kalia RK, Nakano A, Shimojo F, Vashishta P. Semiconductor-metal structural phase transformation in MoTe 2 monolayers by electronic excitation. NANOSCALE 2018; 10:2742-2747. [PMID: 29334101 DOI: 10.1039/c7nr07890k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Optical modulation of the crystal structure and materials properties is an increasingly important technique for functionalization of two-dimensional and layered semiconductors, where traditional methods like chemical doping are ineffective. Controllable transformation between the semiconducting (H) and semimetallic (T') polytypes of transition metal chalcogenide monolayers is of central importance to two-dimensional electronics, and thermally-driven and strain-driven examples of this phase transformation have been previously reported. However, the possibility of a H-T' phase transformation driven by electronic or optical excitation is less explored and little is known about the potential energy surface and the magnitude of activation barriers or the mechanism of the phase transformation in the excited state. Here, we model the electronic and ionic structure of excited MoTe2 crystals and demonstrate how electronic excitation leads to a Fermi-surface-nesting driven softening of phonon modes at the Brillouin zone boundary and the subsequent stabilization of a low-energy intermediate crystal structure along the semiconductor-metal phase transition pathway. The significantly reduced barriers for this transformation upon electronic excitation suggest that optical excitation may enable rapid and controllable synthesis of lateral semiconductor-metal heterophase homojunctions in monolayer materials for use in next-generation two-dimensional nano-electronics applications.
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Affiliation(s)
- Aravind Krishnamoorthy
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089, USA.
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12
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Bang J, Sun YY, Liu XQ, Gao F, Zhang SB. Carrier-Multiplication-Induced Structural Change during Ultrafast Carrier Relaxation and Nonthermal Phase Transition in Semiconductors. PHYSICAL REVIEW LETTERS 2016; 117:126402. [PMID: 27689286 DOI: 10.1103/physrevlett.117.126402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Indexed: 06/06/2023]
Abstract
While being extensively studied as an important physical process to alter exciton population in nanostructures at the fs time scale, carrier multiplication has not been considered seriously as a major mechanism for phase transition. Real-time time-dependent density functional theory study of Ge_{2}Sb_{2}Te_{5} reveals that carrier multiplication can induce an ultrafast phase transition in the solid state despite that the lattice remains cold. The results also unify the experimental findings in other semiconductors for which the explanation remains to be the 30-year old phenomenological plasma annealing model.
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Affiliation(s)
- Junhyeok Bang
- Department of Physics, Applied Physics, & Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
- Spin Engineering Physics Team, Korea Basic Science Institute (KBSI), Daejeon 305-806, Republic of Korea
| | - Y Y Sun
- Department of Physics, Applied Physics, & Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - X-Q Liu
- Department of Physics, Applied Physics, & Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
| | - F Gao
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - S B Zhang
- Department of Physics, Applied Physics, & Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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13
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Han D, Bang J, Xie W, Meunier V, Zhang S. Phonon-Enabled Carrier Transport of Localized States at Non-Polar Semiconductor Surfaces: A First-Principles-Based Prediction. J Phys Chem Lett 2016; 7:3548-3553. [PMID: 27552528 DOI: 10.1021/acs.jpclett.6b01608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electron-phonon coupling can hamper carrier transport either by scattering or by the formation of mass-enhanced polarons. Here, we use time-dependent density functional theory-molecular dynamics simulations to show that phonons can also promote the transport of excited carriers. Using nonpolar InAs (110) surface as an example, we identify phonon-mediated coupling between electronic states close in energy as the origin for the enhanced transport. In particular, the coupling causes localized excitons in the resonant surface states to propagate into bulk with velocities as high as 10(6) cm/s. The theory also predicts temperature enhanced carrier transport, which may be observable in ultrathin nanostructures.
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Affiliation(s)
- Dong Han
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , Changchun 130033, China
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University , Changchun 130012, China
| | - Junhyeok Bang
- Spin Engineering Physics Team, Korea Basic Science Institute (KBSI) , Daejeon 305-806, Republic of Korea
| | - Weiyu Xie
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - Vincent Meunier
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
| | - ShengBai Zhang
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute , Troy, New York 12180, United States
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Bang J, Sun YY, Song JH, Zhang SB. Carrier-induced transient defect mechanism for non-radiative recombination in InGaN light-emitting devices. Sci Rep 2016; 6:24404. [PMID: 27075818 PMCID: PMC4830943 DOI: 10.1038/srep24404] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 03/11/2016] [Indexed: 11/09/2022] Open
Abstract
Non-radiative recombination (NRR) of excited carriers poses a serious challenge to optoelectronic device efficiency. Understanding the mechanism is thus crucial to defect physics and technological applications. Here, by using first-principles calculations, we propose a new NRR mechanism, where excited carriers recombine via a Frenkel-pair (FP) defect formation. While in the ground state the FP is high in energy and is unlikely to form, in the electronic excited states its formation is enabled by a strong electron-phonon coupling of the excited carriers. This NRR mechanism is expected to be general for wide-gap semiconductors, rather than being limited to InGaN-based light emitting devices.
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Affiliation(s)
- Junhyeok Bang
- Department of Physics, Applied Physics & Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
- Spin Engineering Physics Team, Korea Basic Science Institute (KBSI), Daejeon 305-806, South Korea
| | - Y. Y. Sun
- Department of Physics, Applied Physics & Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Jung-Hoon Song
- 182 Shingwan, Department of Physics, Kongju National University, Kongju Chungnam 314-701, South Korea
| | - S. B. Zhang
- Department of Physics, Applied Physics & Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
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Fazzi D, Barbatti M, Thiel W. Unveiling the Role of Hot Charge-Transfer States in Molecular Aggregates via Nonadiabatic Dynamics. J Am Chem Soc 2016; 138:4502-11. [DOI: 10.1021/jacs.5b13210] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Daniele Fazzi
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Mario Barbatti
- Aix Marseille Université, CNRS, ICR UMR7273, 13397 Marseille, France
| | - Walter Thiel
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
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Abstract
Abstract
Catalysis, as a key and enabling technology, plays an increasingly important role in fields ranging from energy, environment and agriculture to health care. Rational design and synthesis of highly efficient catalysts has become the ultimate goal of catalysis research. Thanks to the rapid development of nanoscience and nanotechnology, and in particular a theoretical understanding of the tuning of electronic structure in nanoscale systems, this element of design is becoming possible via precise control of nanoparticles’ composition, morphology, structure and electronic states. At the same time, it is important to develop tools for in situ characterization of nanocatalysts under realistic reaction conditions, and for monitoring the dynamics of catalysis with high spatial, temporal and energy resolution. In this review, we discuss confinement effects in nanocatalysis, a concept that our group has put forward and developed over several years. Taking the confined catalytic systems of carbon nanotubes, metal-confined nano-oxides and 2D layered nanocatalysts as examples, we summarize and analyze the fundamental concepts, the research methods and some of the key scientific issues involved in nanocatalysis. Moreover, we present a perspective on the challenges and opportunities in future research on nanocatalysis from the aspects of: (1) controlled synthesis of nanocatalysts and rational design of catalytically active centers; (2) in situ characterization of nanocatalysts and dynamics of catalytic processes; (3) computational chemistry with a complexity approximating that of experiments; and (4) scale-up and commercialization of nanocatalysts.
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Affiliation(s)
- Fan Yang
- State Key Laboratory of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Dehui Deng
- State Key Laboratory of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xiulian Pan
- State Key Laboratory of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Qiang Fu
- State Key Laboratory of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xinhe Bao
- State Key Laboratory of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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Sahin H, Leenaerts O, Singh SK, Peeters FM. Graphane. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2015. [DOI: 10.1002/wcms.1216] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- H. Sahin
- Department of Physics; University of Antwerp, Groenenborgerlaan 171, BE-2020; Antwerp Belgium
| | - O. Leenaerts
- Department of Physics; University of Antwerp, Groenenborgerlaan 171, BE-2020; Antwerp Belgium
| | - S. K. Singh
- Department of Physics; University of Antwerp, Groenenborgerlaan 171, BE-2020; Antwerp Belgium
| | - F. M. Peeters
- Department of Physics; University of Antwerp, Groenenborgerlaan 171, BE-2020; Antwerp Belgium
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Zeng X, Tu W, Li J, Bao J, Dai Z. Photoelectrochemical biosensor using enzyme-catalyzed in situ propagation of CdS quantum dots on graphene oxide. ACS APPLIED MATERIALS & INTERFACES 2014; 6:16197-203. [PMID: 25154012 DOI: 10.1021/am5043164] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
An innovative photoelectrochemical (PEC) biosensor platform was designed based on the in situ generation of CdS quantum dots (QDs) on graphene oxide (GO) using an enzymatic reaction. Horseradish peroxidase catalyzed the reduction of sodium thiosulfate with hydrogen peroxide to generate H2S, which reacted with Cd(2+) to form CdS QDs. CdS QDs could be photoexcited to generate an elevated photocurrent as a readout signal. This strategy offered a "green" alternative to inconvenient presynthesis procedures for the fabrication of semiconducting nanoparticles. The nanomaterials and assembly procedures were characterized by microscopy and spectroscopy techniques. Combined with immune recognition and on the basis of the PEC activity of CdS QDs on GO, the strategy was successfully applied to a PEC assay to detect carcinoembryonic antigen and displayed a wide linear range from 2.5 ng mL(-1) to 50 μg mL(-1) and a detection limit of 0.72 ng mL(-1) at a signal-to-noise ratio of 3. The PEC biosensor showed satisfactory performance for clinical sample detection and was convenient for determining high concentrations of solute without dilution. This effort offers a new opportunity for the development of numerous rapid and convenient analytical techniques using the PEC method that may be applied in the design and preparation of various solar-energy-driven applications.
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Affiliation(s)
- Xianxiang Zeng
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials and Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Materials Science, Nanjing Normal University , Nanjing, 210023 Jiangsu, People's Republic of China
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Kang J, Wei SH. Tunable Anderson localization in hydrogenated graphene based on the electric field effect. PHYSICAL REVIEW LETTERS 2013; 111:216801. [PMID: 24313510 DOI: 10.1103/physrevlett.111.216801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Indexed: 06/02/2023]
Abstract
Effective control of hydrogenation of graphene is of great scientific and technological importance. However, the reversible control of H density (n(H)) on graphene is difficult due to the irreversible H2 formation of the detached H adatoms. Here we present a novel mechanism for controlling n(H) by using the unique proton transfer reaction between NH3 gas and hydrogenated graphene, which can be tuned by applying perpendicular electric fields. Using first-principles calculations, we show that n(H) can be reversibly tuned by the applied electric fields around the critical density for the Anderson localization in hydrogenated graphene. The proposed field-induced control of H adsorption or desorption on graphene opens a path toward the development of new graphene transistors based on the tunable degree of disorder.
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Affiliation(s)
- Joongoo Kang
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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