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Nhat Quyen N, Tzeng WY, Hsu CE, Lin IA, Chen WH, Jia HH, Wang SC, Liu CE, Chen YS, Chen WL, Chou TL, Wang IT, Kuo CN, Lin CL, Wu CT, Lin PH, Weng SC, Cheng CM, Kuo CY, Tu CM, Chu MW, Chang YM, Lue CS, Hsueh HC, Luo CW. Three-dimensional ultrafast charge-density-wave dynamics in CuTe. Nat Commun 2024; 15:2386. [PMID: 38493205 PMCID: PMC10944522 DOI: 10.1038/s41467-024-46615-y] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 03/04/2024] [Indexed: 03/18/2024] Open
Abstract
Charge density waves (CDWs) involved with electronic and phononic subsystems simultaneously are a common quantum state in solid-state physics, especially in low-dimensional materials. However, CDW phase dynamics in various dimensions are yet to be studied, and their phase transition mechanism is currently moot. Here we show that using the distinct temperature evolution of orientation-dependent ultrafast electron and phonon dynamics, different dimensional CDW phases are verified in CuTe. When the temperature decreases, the shrinking of c-axis length accompanied with the appearance of interchain and interlayer interactions causes the quantum fluctuations (QF) of the CDW phase until 220 K. At T < 220 K, the CDWs on the different ab-planes are finally locked with each other in anti-phase to form a CDW phase along the c-axis. This study shows the dimension evolution of CDW phases in one CDW system and their stabilized mechanisms in different temperature regimes.
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Grants
- 112-2119-M-A49-012-MBK Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- 109-2112-M-009-020-MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- 109-2124-M-009-003-MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- 109-2119-M-002 -026 -MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- 108-2112-M-002-013-MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- 111-2124-M-213-001 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- 108-2112-M-002 -013 -MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- 109-2119-M-002 -026 -MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- 112-2124-M-006-009 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- 110-2112-M-032-014-MY3 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- Ministry of Education (Ministry of Education, Republic of China (Taiwan))
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Affiliation(s)
- Nguyen Nhat Quyen
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Wen-Yen Tzeng
- Department of Electronic Engineering, National Formosa University, Yunlin, 632, Taiwan
| | - Chih-En Hsu
- Department of Physics, Tamkang University, New Taipei City, 251301, Taiwan
| | - I-An Lin
- Department of Physics, Tamkang University, New Taipei City, 251301, Taiwan
| | - Wan-Hsin Chen
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Hao-Hsiang Jia
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Sheng-Chiao Wang
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Cheng-En Liu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Yu-Sheng Chen
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Wei-Liang Chen
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, 10617, Taiwan
| | - Ta-Lei Chou
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, 10617, Taiwan
| | - I-Ta Wang
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, 10617, Taiwan
| | - Chia-Nung Kuo
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Chun-Liang Lin
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Chien-Te Wu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, Taiwan
| | - Ping-Hui Lin
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Cheng-Maw Cheng
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Chang-Yang Kuo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Chien-Ming Tu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
- Undergraduate Degree Program of Systems Engineering and Technology, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan
- Chung Cheng Institute of Technology, National Defense University, Taoyuan, 335009, Taiwan
| | - Ming-Wen Chu
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, 10617, Taiwan
- Center of Atomic Initiative for New Materials (AI-MAT), National Taiwan University, Taipei, 10617, Taiwan
| | - Yu-Ming Chang
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, 10617, Taiwan
- Center of Atomic Initiative for New Materials (AI-MAT), National Taiwan University, Taipei, 10617, Taiwan
| | - Chin Shan Lue
- Department of Physics, National Cheng Kung University, Tainan, 70101, Taiwan.
- Taiwan Consortium of Emergent Crystalline Materials (TCECM), National Science and Technology Council, Taipei, 10601, Taiwan.
| | - Hung-Chung Hsueh
- Department of Physics, Tamkang University, New Taipei City, 251301, Taiwan.
| | - Chih-Wei Luo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan.
- Taiwan Consortium of Emergent Crystalline Materials (TCECM), National Science and Technology Council, Taipei, 10601, Taiwan.
- Institute of Physics and Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan.
- Department of Physics, University of Washington, Seattle, Washington, 98195, USA.
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2
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Liu RY, Huang A, Sankar R, Hlevyack JA, Su CC, Weng SC, Lin MK, Chen P, Cheng CM, Denlinger JD, Mo SK, Fedorov AV, Chang CS, Jeng HT, Chuang TM, Chiang TC. Dirac Nodal Line in Hourglass Semimetal Nb 3SiTe 6. Nano Lett 2023; 23:380-388. [PMID: 36382909 DOI: 10.1021/acs.nanolett.2c03293] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Glide-mirror symmetry in nonsymmorphic crystals can foster the emergence of novel hourglass nodal loop states. Here, we present spectroscopic signatures from angle-resolved photoemission of a predicted topological hourglass semimetal phase in Nb3SiTe6. Linear band crossings are observed at the zone boundary of Nb3SiTe6, which could be the origin of the nontrivial Berry phase and are consistent with a predicted glide quantum spin Hall effect; such linear band crossings connect to form a nodal loop. Furthermore, the saddle-like Fermi surface of Nb3SiTe6 observed in our results helps unveil linear band crossings that could be missed. In situ alkali-metal doping of Nb3SiTe6 also facilitated the observation of other band crossings and parabolic bands at the zone center correlated with accidental nodal loop states. Overall, our results complete the system's band structure, help explain prior Hall measurements, and suggest the existence of a nodal loop at the zone center of Nb3SiTe6.
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Affiliation(s)
- Ro-Ya Liu
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois61801, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois61801, United States
- Institute of Physics, Academia Sinica, Taipei11529, Taiwan
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
- National Synchrotron Radiation Research Center, Hsinchu30076, Taiwan
| | - Angus Huang
- Department of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
| | - Raman Sankar
- Institute of Physics, Academia Sinica, Taipei11529, Taiwan
| | - Joseph Andrew Hlevyack
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois61801, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois61801, United States
| | - Chih-Chuan Su
- Institute of Physics, Academia Sinica, Taipei11529, Taiwan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu30076, Taiwan
| | - Meng-Kai Lin
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois61801, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois61801, United States
| | - Peng Chen
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science and Shanghai Center for Complex Physics, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai200240, China
| | - Cheng-Maw Cheng
- National Synchrotron Radiation Research Center, Hsinchu30076, Taiwan
| | - Jonathan D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Alexei V Fedorov
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | | | - Horng-Tay Jeng
- Institute of Physics, Academia Sinica, Taipei11529, Taiwan
- Department of Physics, National Tsing Hua University, Hsinchu30013, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei10617, Taiwan
| | | | - Tai-Chang Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois61801, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois61801, United States
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3
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Dai J, Zhu Y, Chen Y, Wen X, Long M, Wu X, Hu Z, Guan D, Wang X, Zhou C, Lin Q, Sun Y, Weng SC, Wang H, Zhou W, Shao Z. Hydrogen spillover in complex oxide multifunctional sites improves acidic hydrogen evolution electrocatalysis. Nat Commun 2022; 13:1189. [PMID: 35246542 PMCID: PMC8897394 DOI: 10.1038/s41467-022-28843-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 02/11/2022] [Indexed: 11/18/2022] Open
Abstract
Improving the catalytic efficiency of platinum for the hydrogen evolution reaction is valuable for water splitting technologies. Hydrogen spillover has emerged as a new strategy in designing binary-component Pt/support electrocatalysts. However, such binary catalysts often suffer from a long reaction pathway, undesirable interfacial barrier, and complicated synthetic processes. Here we report a single-phase complex oxide La2Sr2PtO7+δ as a high-performance hydrogen evolution electrocatalyst in acidic media utilizing an atomic-scale hydrogen spillover effect between multifunctional catalytic sites. With insights from comprehensive experiments and theoretical calculations, the overall hydrogen evolution pathway proceeds along three steps: fast proton adsorption on O site, facile hydrogen migration from O site to Pt site via thermoneutral La-Pt bridge site serving as the mediator, and favorable H2 desorption on Pt site. Benefiting from this catalytic process, the resulting La2Sr2PtO7+δ exhibits a low overpotential of 13 mV at 10 mA cm−2, a small Tafel slope of 22 mV dec−1, an enhanced intrinsic activity, and a greater durability than commercial Pt black catalyst. While renewable H2 production offers a promising route for clean energy production, there is an urgent need to improve catalyst performances. Here, authors design a Pt-containing complex oxide that utilizes atomic-scale hydrogen spillover to promote H2 evolution electrocatalysis in acidic media.
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Affiliation(s)
- Jie Dai
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 211800, China
| | - Yinlong Zhu
- Department of Chemical Engineering, Monash University, Clayton, VIC, 3800, Australia.
| | - Yu Chen
- Monash Centre for Electron Microscopy, Monash University, Clayton, VIC, 3800, Australia
| | - Xue Wen
- School of Environmental Science and Engineering, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Mingce Long
- School of Environmental Science and Engineering, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xinhao Wu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 211800, China
| | - Zhiwei Hu
- Max Planck Institute for Chemical Physics of Solids, Nothnitzer Strasse 40, 01187, Dresden, Germany
| | - Daqin Guan
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 211800, China
| | - Xixi Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 211800, China
| | - Chuan Zhou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 211800, China
| | - Qian Lin
- Department of Chemical Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Yifei Sun
- College of Energy, Xiamen University, Xiamen, 361102, China
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu, 30076, Taiwan
| | - Huanting Wang
- Department of Chemical Engineering, Monash University, Clayton, VIC, 3800, Australia
| | - Wei Zhou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 211800, China
| | - Zongping Shao
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 211800, China. .,WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Perth, WA, 6845, Australia.
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4
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Su SH, Chuang PY, Chen HY, Weng SC, Chen WC, Tsuei KD, Lee CK, Yu SH, Chou MMC, Tu LW, Jeng HT, Tu CM, Luo CW, Cheng CM, Chang TR, Huang JCA. Topological Proximity-Induced Dirac Fermion in Two-Dimensional Antimonene. ACS Nano 2021; 15:15085-15095. [PMID: 34435764 DOI: 10.1021/acsnano.1c05454] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Antimonene is a promising two-dimensional (2D) material that is calculated to have a significant fundamental bandgap usable for advanced applications such as field-effect transistors, photoelectric devices, and the quantum-spin Hall (QSH) state. Herein, we demonstrate a phenomenon termed topological proximity effect, which occurs between a 2D material and a three-dimensional (3D) topological insulator (TI). We provide strong evidence derived from hydrogen etching on Sb2Te3 that large-area and well-ordered antimonene presents a 2D topological state. Delicate analysis with a scanning tunneling microscope of the evolutionary intermediates reveals that hydrogen etching on Sb2Te3 resulted in the formation of a large area of antimonene with a buckled structure. A topological state formed in the antimonene/Sb2Te3 heterostructure was confirmed with angle-resolved photoemission spectra and density-functional theory calculations; in particular, the Dirac point was located almost at the Fermi level. The results reveal that Dirac fermions are indeed realized at the interface of a 2D normal insulator (NI) and a 3D TI as a result of strong hybridization between antimonene and Sb2Te3. Our work demonstrates that the position of the Dirac point and the shape of the Dirac surface state can be tuned by varying the energy position of the NI valence band, which modifies the direction of the spin texture of Sb-BL/Sb2Te3 via varying the Fermi level. This topological phase in 2D-material engineering has generated a paradigm in that the topological proximity effect at the NI/TI interface has been realized, which demonstrates a way to create QSH systems in 2D-material TI heterostructures.
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Affiliation(s)
- Shu Hsuan Su
- Department of Physics, National Cheng Kung University, Taiwan 701, Taiwan
| | - Pei-Yu Chuang
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Hsin-Yu Chen
- Department of Physics, National Cheng Kung University, Taiwan 701, Taiwan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Wei-Chuan Chen
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Ku-Ding Tsuei
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
| | - Chao-Kuei Lee
- Department of Photonics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Research Center for Applied Sciences, Academia Sinica, 187 Academia Road, Taipei 11529, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Shih-Hsun Yu
- Department of Materials and Optoelectronics Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Mitch M-C Chou
- Department of Materials and Optoelectronics Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Li-Wei Tu
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- Physics Division, National Center for Theoretical Sciences, Hsinchu 30013, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Chien-Ming Tu
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
| | - Chih-Wei Luo
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
- Institute of Physics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Cheng-Maw Cheng
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106335, Taiwan
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Taiwan 701, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan 701, Taiwan
- Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Jung-Chun Andrew Huang
- Department of Physics, National Cheng Kung University, Taiwan 701, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
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5
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Su BK, Wei YC, Chuang WT, Weng SC, Wang SF, Chen DG, Huang ZX, Chi Y, Chou PT. The Observation of Interchain Motion in Self-Assembled Crystalline Platinum(II) Complexes: An Exquisite Case but By No Means the Only One in Molecular Solids. J Phys Chem Lett 2021; 12:7482-7489. [PMID: 34342467 DOI: 10.1021/acs.jpclett.1c01677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In organic and organometallic solids, upon electronic excitation, most intermolecular structural relaxations follow a pathway along the π-π stacking direction or metal-metal bond with significant coupling strength. Differently, we discovered that the self-assembled platinum(II) complexes, Pt(fppz)2, exhibit an unusual interchain contraction. The ground-state and excited-state multiple local minima were distinguished by temperature-dependent excitation/emission spectra, indicating the existence of multiple local minima. The time-resolved emission decay revealed the excited-state structural relaxation lifetime with τobs = 41 ns at 298 K. Temperature-dependent X-ray diffraction analysis showed that the packing geometries contract 0.6 Å along the interchain direction (a-axis) at 50 K compared to the geometries at 298 K. Such structural displacements render the slow internal conversion rate in the excited states. We thus demonstrate the correlation between the packing geometries and the excited-state dynamics of the self-assembled Pt(II) complexes, shedding light on the unique direction of interchain structural deformation of the molecular aggregates.
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Affiliation(s)
- Bo-Kang Su
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yu-Chen Wei
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Wei-Tsung Chuang
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Sheng-Fu Wang
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Deng-Gao Chen
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Zhi-Xuan Huang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yun Chi
- Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan
- Department of Materials Science and Engineering, Department of Chemistry, and Center of Super-Diamond and Advanced Films, City University of Hong Kong, Kowloon 999077, Hong Kong SAR
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
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6
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Wang X, Liu Z, Ye X, Zhou B, Hu Z, Wang W, Yu R, Agrestini S, Zhou G, Chen K, Choueikani F, Ohresser P, Baudelet F, Lin HJ, Chen CT, Tanaka A, Weng SC, Long Y. Os Doping Suppressed Cu-Fe Charge Transfer and Induced Structural and Magnetic Phase Transitions in LaCu 3Fe 4-xOs xO 12 ( x = 1 and 2). Inorg Chem 2021; 60:6298-6305. [PMID: 33848160 DOI: 10.1021/acs.inorgchem.1c00009] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
B-site Os-doped quadruple perovskite oxides LaCu3Fe4-xOsxO12 (x = 1 and 2) were prepared under high-pressure and high-temperature conditions. Although parent compound LaCu3Fe4O12 experiences Cu-Fe intermetallic charge transfer that changes the Cu3+/Fe3+ charge combination to Cu2+/Fe3.75+ at 393 K, in the Os-doped samples, the Cu and Fe charge states are found to be constant 2+ and 3+, respectively, indicating the complete suppression of charge transfer. Correspondingly, Os6+ and mixed Os4.5+ valence states are determined by X-ray absorption spectroscopy for x = 1 and x = 2 compositions, respectively. The x = 1 sample crystallizes in an Fe/Os disordered structure with the Im3̅ space group. It experiences a spin-glass transition around 480 K. With further Os substitution up to x = 2, the crystal symmetry changes to Pn3̅, where Fe and Os are orderly distributed in a rocksalt-type fashion at the B site. Moreover, this composition shows a long-range Cu2+(↑)Fe3+(↑)Os4.5+(↓) ferrimagnetic ordering near 520 K. This work provides a rare example for 5d substitution-suppressed intermetallic charge transfer as well as induced structural and magnetic phase transitions with high spin ordering temperature.
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Affiliation(s)
- Xiao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
| | - Zhehong Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xubin Ye
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bowen Zhou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiwei Hu
- Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany
| | - Weipeng Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Richeng Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Stefano Agrestini
- Max Planck Institute for Chemical Physics of Solids, Dresden 01187, Germany.,ALBA Synchrotron Light Source, E-08290 Cerdanyola del Vallès, Barcelona, Spain
| | - Guanghui Zhou
- Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications of Hunan, Hunan Normal University, Changsha 410081, China
| | - Kai Chen
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, Cedex, France
| | - Fadi Choueikani
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, Cedex, France
| | - Philippe Ohresser
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, Cedex, France
| | - François Baudelet
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, Cedex, France
| | - Hong-Ji Lin
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chien-Te Chen
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Arata Tanaka
- Quantum Matter Program, Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-hiroshima 739-8530, Japan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Youwen Long
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.,Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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7
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Wu TS, Syu LY, Lin BH, Weng SC, Jeng HT, Huang YS, Soo YL. Reduction of dopant ions and enhancement of magnetic properties by UV irradiation in Ce-doped TiO 2. Sci Rep 2021; 11:7668. [PMID: 33828150 PMCID: PMC8027894 DOI: 10.1038/s41598-021-87115-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 03/22/2021] [Indexed: 11/09/2022] Open
Abstract
We report the experimental observation of and theoretical explanation for the reduction of dopant ions and enhancement of magnetic properties in Ce-doped TiO2 diluted magnetic semiconductors from UV-light irradiation. Substantial increase in Ce3+ concentration and creation of oxygen vacancy defects in the sample due to UV-light irradiation was observed by X-ray and optical methods. Magnetic measurements demonstrate a combination of paramagnetism and ferromagnetism up to room temperatures in all samples. The magnetization of both paramagnetic and ferromagnetic components was observed to be dramatically enhanced in the irradiated sample. First-principle theoretical calculations show that valence holes created by UV irradiation can substantially lower the formation energy of oxygen vacancies. While the electron spin densities for defect states near oxygen vacancies in pure TiO2 are in antiferromagnetic orientation, they are in ferromagnetic orientations in Ce-doped TiO2. Therefore, the ferromagnetically-oriented spin densities near oxygen vacancies created by UV irradiation are the most probable cause for the experimentally observed enhancement of magnetism in the irradiated Ce-doped TiO2.
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Affiliation(s)
- Tai-Sing Wu
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Leng-You Syu
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
| | - Bi-Hsuan Lin
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan.,Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Yu-Shan Huang
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Yun-Liang Soo
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan. .,Department of Physics, National Tsing Hua University, Hsinchu, Taiwan.
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8
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Chang YY, Tsai YW, Weng SC, Chen SL, Chang SL. Integrated optical chip for a high-resolution, single-resonance-mode x-ray monochromator system. Opt Lett 2021; 46:416-419. [PMID: 33449043 DOI: 10.1364/ol.409833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
An integrated optical chip that minimizes the size of the energy-tuning single-resonance-mode x-ray monochromator system into a 3cm×5cm silicon wafer is proposed. A Fabry-Perot x-ray resonator and two back-reflecting Si mirrors are employed on the wafer as the optical components, where Si(12 4 0) back reflection is used for both Fabry-Perot resonance and re-diffraction of the x-ray beams from the resonator in the incident direction. We can achieve an energy bandwidth of 3.4 meV in single-mode x rays and tune the energy by temperature variation. Such Si chips can be readily employed at the synchrotron beamlines and conventional x-ray laboratories for high-resolution investigations.
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9
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Ye X, Liu Z, Wang W, Hu Z, Lin HJ, Weng SC, Chen CT, Yu R, Tjeng LH, Long Y. High-pressure synthesis and spin glass behavior of a Mn/Ir disordered quadruple perovskite CaCu 3Mn 2Ir 2O 12. J Phys Condens Matter 2020; 32:075701. [PMID: 31675747 DOI: 10.1088/1361-648x/ab5386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A new 3d-5d hybridized quadruple perovskite oxide, CaCu3Mn2Ir2O12, was synthesized by high-pressure and high-temperature methods. The Rietveld structure analysis reveals that the compound crystallizes in an [Formula: see text]-type perovskite structure with space group Im-3, where the Ca and Cu are 1:3 ordered at fixed atomic positions. At the B site the 3d Mn and the 5d Ir ions are disorderly distributed due to the rare equal +4 charge states for both of them as determined by x-ray absorption spectroscopy. The competing antiferromagnetic and ferromagnetic interactions among Cu2+, Mn4+, and Ir4+ ions give rise to spin glass behavior, which follows a conventional dynamical slowing down model.
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Affiliation(s)
- Xubin Ye
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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10
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Hung PS, Chung WA, Chou SC, Tso KC, Chang CK, Wang GR, Guo WQ, Weng SC, Wu PW. Composite NiCoO 2/NiCo 2O 4 inverse opals for the oxygen evolution reaction in an alkaline electrolyte. Catal Sci Technol 2020. [DOI: 10.1039/d0cy01218a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The inverse opals exhibit a 3D ordered macroporous framework, which provides an excessive surface area and facile mass transport. A conformal NiCoOx functional coating further renders these materials with increased reactivity in OER catalysis.
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Affiliation(s)
- Pei-Sung Hung
- Department of Materials Science and Engineering
- National Chiao Tung University
- Hsinchu 300
- ROC
| | - Wei-An Chung
- Department of Materials Science and Engineering
- National Chiao Tung University
- Hsinchu 300
- ROC
| | - Shih-Cheng Chou
- Department of Materials Science and Engineering
- National Chiao Tung University
- Hsinchu 300
- ROC
| | - Kuang-Chih Tso
- Graduate Program for Science and Technology of Accelerator Light Source
- National Chiao Tung University
- Hsinchu 300
- ROC
| | - Chung-Kai Chang
- Department of Materials Science and Engineering
- National Chiao Tung University
- Hsinchu 300
- ROC
| | - Guang-Ren Wang
- Department of Materials Science and Engineering
- National Chiao Tung University
- Hsinchu 300
- ROC
| | - Wei-Qing Guo
- Department of Materials Science and Engineering
- National Chiao Tung University
- Hsinchu 300
- ROC
| | | | - Pu-Wei Wu
- Department of Materials Science and Engineering
- National Chiao Tung University
- Hsinchu 300
- ROC
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11
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Gao L, Wang X, Ye X, Wang W, Liu Z, Qin S, Hu Z, Lin HJ, Weng SC, Chen CT, Ohresser P, Baudelet F, Yu R, Jin C, Long Y. Near-Room-Temperature Ferrimagnetic Ordering in a B-Site-Disordered 3d-5d-Hybridized Quadruple Perovskite Oxide, CaCu 3Mn 2Os 2O 12. Inorg Chem 2019; 58:15529-15535. [PMID: 31702150 DOI: 10.1021/acs.inorgchem.9b02576] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new 3d-5d hybridization oxide, CaCu3Mn2Os2O12 (CCMOO), was prepared by high-pressure and high-temperature synthesis methods. The compound crystallizes to an A-site-ordered but B-site-disordered quadruple perovskite structure with a space group of Im3̅ (No. 204). The charge states of the transition metals are determined to be Cu2+/Mn3.5+/Os4.5+ by X-ray absorption spectroscopy. Although most B-site-disordered perovskites possess lower spin-ordering temperatures or even nonmagnetic transitions, the current CCMOO displays a long-range ferrimagnetic phase transition with a critical temperature as high as ∼280 K. Moreover, a large saturated magnetic moment is found to occur [7.8 μB/formula units (f.u.) at 2 K]. X-ray magnetic circular dichroism shows a Cu2+(↑)Mn3.5+(↑)Os4.5+(↓) ferrimagnetic coupling. The corner-sharing Mn/OsO6 octahedra with mixed Mn and Os charge states make the compound metallic in electrical transport, in agreement with a specific heat fitting at low temperature. This work provides a rare example with high spin-ordering temperature and a large magnetic moment in B-site-disordered 3d-5d hybridization perovskite oxides.
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Affiliation(s)
- Lei Gao
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China.,School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xiao Wang
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China.,School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Xubin Ye
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China.,School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Weipeng Wang
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China
| | - Zhehong Liu
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China.,School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Shijun Qin
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China.,School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Zhiwei Hu
- Max Planck Institute for Chemical Physics of Solids , Dresden 01187 , Germany
| | - Hong-Ji Lin
- National Synchrotron Radiation Research Center , Hsinchu 30076 , Taiwan, Republic of China
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center , Hsinchu 30076 , Taiwan, Republic of China
| | - Chien-Te Chen
- National Synchrotron Radiation Research Center , Hsinchu 30076 , Taiwan, Republic of China
| | - Philippe Ohresser
- L'Orme des Merisiers , Synchrotron SOLEIL , Saint-Aubin, Gif-sur-Yvette Cedex 91192 , France
| | - Francois Baudelet
- L'Orme des Merisiers , Synchrotron SOLEIL , Saint-Aubin, Gif-sur-Yvette Cedex 91192 , France
| | - Richeng Yu
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China.,School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Changqing Jin
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China.,School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China.,Songshan Lake Materials Laboratory , Dongguan , Guangdong 523808 , China
| | - Youwen Long
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China.,School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100049 , China.,Songshan Lake Materials Laboratory , Dongguan , Guangdong 523808 , China
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12
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Kang JJ, Yang TY, Lan YK, Wu WR, Su CJ, Weng SC, Yamada NL, Su AC, Jeng US. Directed Vertical Diffusion of Photovoltaic Active Layer Components into Porous ZnO-Based Cathode Buffer Layers. Small 2018; 14:e1704310. [PMID: 29498203 DOI: 10.1002/smll.201704310] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 01/13/2018] [Indexed: 06/08/2023]
Abstract
Cathode buffer layers (CBLs) can effectively further the efficiency of polymer solar cells (PSCs), after optimization of the active layer. Hidden between the active layer and cathode of the inverted PSC device configuration is the critical yet often unattended vertical diffusion of the active layer components across CBL. Here, a novel methodology of contrast variation with neutron and anomalous X-ray reflectivity to map the multicomponent depth compositions of inverted PSCs, covering from the active layer surface down to the bottom of the ZnO-based CBL, is developed. Uniquely revealed for a high-performance model PSC are the often overlooked porosity distributions of the ZnO-based CBL and the differential diffusions of the polymer PTB7-Th and fullerene derivative PC71 BM of the active layer into the CBL. Interface modification of the ZnO-based CBL with fullerene derivative PCBEOH for size-selective nanochannels can selectively improve the diffusion of PC71 BM more than that of the polymer. The deeper penetration of PC71 BM establishes a gradient distribution of fullerene derivatives over the ZnO/PCBE-OH CBL, resulting in markedly improved electron mobility and device efficiency of the inverted PSC. The result suggests a new CBL design concept of progressive matching of the conduction bands.
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Affiliation(s)
- Jia-Jhen Kang
- National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu, 30076, Taiwan
| | - Tsung-Yu Yang
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Yi-Kang Lan
- Materials and Electro-Optic Research Division, National Chung Shan Institute of Science and Technology, Taoyuan, 32546, Taiwan
| | - Wei-Ru Wu
- National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu, 30076, Taiwan
| | - Chun-Jen Su
- National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu, 30076, Taiwan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu, 30076, Taiwan
| | - Norifumi L Yamada
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tokai, Naka, 319-1106, Japan
| | - An-Chung Su
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - U-Ser Jeng
- National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu, 30076, Taiwan
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
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13
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Chuang PY, Su SH, Chong CW, Chen YF, Chou YH, Huang JCA, Chen WC, Cheng CM, Tsuei KD, Wang CH, Yang YW, Liao YF, Weng SC, Lee JF, Lan YK, Chang SL, Lee CH, Yang CK, Su HL, Wu YC. Anti-site defect effect on the electronic structure of a Bi2Te3 topological insulator. RSC Adv 2018. [DOI: 10.1039/c7ra08995c] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Tuning the Fermi level (EF) in Bi2Te3 topological-insulator (TI) films is demonstrated on controlling the temperature of growth with molecular-beam epitaxy (MBE).
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14
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Chia HC, Sheu HS, Hsiao YY, Li SS, Lan YK, Lin CY, Chang JW, Kuo YC, Chen CH, Weng SC, Su CJ, Su AC, Chen CW, Jeng US. Critical Intermediate Structure That Directs the Crystalline Texture and Surface Morphology of Organo-Lead Trihalide Perovskite. ACS Appl Mater Interfaces 2017; 9:36897-36906. [PMID: 28984127 DOI: 10.1021/acsami.7b12378] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We have identified an often observed yet unresolved intermediate structure in a popular processing with dimethylformamide solutions of lead chloride and methylammonium iodide for perovskite solar cells. With subsecond time-resolved grazing-incidence X-ray scattering and X-ray photoemission spectroscopy, supplemental with ab initio calculation, the resolved intermediate structure (CH3NH3)2PbI2Cl2·CH3NH3I features two-dimensional (2D) perovskite bilayers of zigzagged lead-halide octahedra and sandwiched CH3NH3I layers. Such intermediate structure reveals a hidden correlation between the intermediate phase and the composition of the processing solution. Most importantly, the 2D perovskite lattice of the intermediate phase is largely crystallographically aligned with the [110] planes of the three-dimensional perovskite cubic phase; consequently, with sublimation of Cl ions from the organo-lead octahedral terminal corners in prolonged annealing, the zigzagged octahedral layers of the intermediate phase can merge with the intercalated methylammonium iodide layers for templated growth of perovskite crystals. Regulated by annealing temperature and the activation energies of the intermediate and perovskite, deduced from analysis of temperature-dependent structural kinetics, the intermediate phase is found to selectively mature first and then melt along the layering direction for epitaxial conversion into perovskite crystals. The unveiled epitaxial conversion under growth kinetics controls might be general for solution-processed and intermediate-templated perovskite formation.
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Affiliation(s)
- Hao-Chung Chia
- Department of Chemical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Hwo-Shuenn Sheu
- National Synchrotron Radiation Research Center , Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Yu-Yun Hsiao
- Department of Materials Science and Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - Shao-Sian Li
- Department of Materials Science and Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - Yi-Kang Lan
- Materials and Electro-Optic Research Division, National Chung-Shan Institute of Science and Technology , Taoyuan 32546, Taiwan
| | - Chung-Yao Lin
- Department of Chemical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Je-Wei Chang
- Department of Chemical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Yen-Chien Kuo
- National Synchrotron Radiation Research Center , Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Chia-Hao Chen
- National Synchrotron Radiation Research Center , Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Shih-Chang Weng
- National Synchrotron Radiation Research Center , Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Chun-Jen Su
- National Synchrotron Radiation Research Center , Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - An-Chung Su
- Department of Chemical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
| | - Chun-Wei Chen
- Department of Materials Science and Engineering, National Taiwan University , Taipei 10617, Taiwan
| | - U-Ser Jeng
- Department of Chemical Engineering, National Tsing Hua University , Hsinchu 30013, Taiwan
- National Synchrotron Radiation Research Center , Hsinchu Science Park, Hsinchu 30076, Taiwan
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15
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Wu TS, Chen YW, Weng SC, Lin CN, Lai CH, Huang YJ, Jeng HT, Chang SL, Soo YL. Dramatic band gap reduction incurred by dopant coordination rearrangement in Co-doped nanocrystals of CeO 2. Sci Rep 2017; 7:4715. [PMID: 28680089 PMCID: PMC5498595 DOI: 10.1038/s41598-017-05046-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 05/24/2017] [Indexed: 11/09/2022] Open
Abstract
A dramatic band gap narrowing of 1.61 eV has been observed in Co-doped nanocrystals of CeO2 (ceria), as a result of thermal annealing, without changing the ceria crystal structure and the Co concentration. As demonstrated by x-ray absorption fine structures, thermal annealing incurs an oxygen coordination rearrangement around Co atoms from an octahedral coordination to a square-planar coordination. First principle calculation using density functional theory reveals two stable oxygen coordination types surrounding Co, consistent with the experimental observation. The band gap values calculated for the two stable coordination types differ dramatically, reproducing the experimentally observed band gap narrowing. These prominent effects due to local structure rearrangement around dopant atoms can lead to unprecedented methods for band gap engineering in doped nanocrystal oxides.
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Affiliation(s)
- T S Wu
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
| | - Y W Chen
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
| | - S C Weng
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - C N Lin
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - C H Lai
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Y J Huang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - H T Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan.,Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - S L Chang
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan.,National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | - Y L Soo
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan. .,National Synchrotron Radiation Research Center, Hsinchu, Taiwan.
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16
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Weng SC, Lee YR, Chen CG, Chu CH, Soo YL, Chang SL. Direct observation of charge ordering in magnetite using resonant multiwave x-ray diffraction. Phys Rev Lett 2012; 108:146404. [PMID: 22540813 DOI: 10.1103/physrevlett.108.146404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Indexed: 05/12/2023]
Abstract
Charge disproportion at octahedral Fe sites in magnetite was observed at low temperature using two inversion-symmetry related three-wave resonant x-ray diffraction, 022-311 and 002-̅3̅1, near the iron K edge. Both of the three-wave cases involve the (002) forbidden-weak reflection. The self-normalized three-wave to two-wave (002) diffraction intensity ratio automatically cancels the self-absorption effect and leads to direct determination of charge disproportion for magnetite below 120 K. This approach provides a more direct and effective way for extracting charge-ordering information.
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Affiliation(s)
- Shih-Chang Weng
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan, ROC
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17
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Lee YR, Stetsko YP, Sun WH, Weng SC, Cheng SY, Lin GG, Soo YL, Chang SL. Multiple wave diffraction anomalous fine structure. Phys Rev Lett 2006; 97:185502. [PMID: 17155552 DOI: 10.1103/physrevlett.97.185502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Indexed: 05/12/2023]
Abstract
A new method, multiple-wave diffraction anomalous fine structure, combining the x-ray multiple-wave diffraction and diffraction anomalous fine structure techniques, is proposed. The real part of dispersion correction Deltaf' and fine structure chi function can be obtained directly by multiple diffraction analysis without using Kramers-Krönig relations and kinematical fitting of diffracted intensity. Better wave vector sensitivity of the fine structure is expected. The multiple-wave diffraction anomalous fine structure experiment for a GaAs single crystal is reported as an example.
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Affiliation(s)
- Yen-Ru Lee
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan, Republic of China 300
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18
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Liou YH, Lo SL, Lin CI, Hu CY, Kuan WH, Weng SC. Methods for accelerating nitrate reduction using zerovalent iron at near-neutral pH: effects of H2-reducing pretreatment and copper deposition. Environ Sci Technol 2005; 39:9643-8. [PMID: 16475346 DOI: 10.1021/es048038p] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Both surface treatments, H2-reducing pretreatment at 400 degrees C and the deposition of copper as a catalyst, were attempted to enhance the removal of nitrate (40 (mg N) L(-1)) using zerovalent iron in a HEPES buffered solution at a pH of between 6.5 and 7.5. After the iron surface was pretreated with hydrogen gas, the removal of the passive oxide layers that covered the iron was indicated by the decline in the oxygen fraction (energy dispersive X-ray analysis) and the overlap of the cyclic polarization curves. The reaction rate was doubled, and the lag of the early period disappeared. Then, the deposition of copper onto freshly pretreated iron promoted nitrate degradation more effectively than that onto a nonpretreated iron surface, because of the high dispersion and small size of the copper particles. An optimum of 0.25-0.5% (w/w) Cu/Fe accelerated the rate by more than six times that of the nonpretreated iron. The aged 0.5% (w/w) Cu/Fe with continual dipping in nitrate solution for 20 days completely restored its reactivity by a regeneration process with H2 reduction. Hence, these two iron surface treatments considerably promoted the removal of nitrate from near-neutral water; the reactivity of Cu/Fe was effectively recovered.
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Affiliation(s)
- Y H Liou
- Research Center for Environmental Pollution Prevention and Control Technology, Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan, ROC
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19
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Kuo YC, Weng SC, Chou CJ, Chang TT, Tsai WJ. Activation and proliferation signals in primary human T lymphocytes inhibited by ergosterol peroxide isolated from Cordyceps cicadae. Br J Pharmacol 2003; 140:895-906. [PMID: 14504132 PMCID: PMC1574094 DOI: 10.1038/sj.bjp.0705500] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Effects of ergosterol peroxide (C28H44O3; Cpd 6A) from Cordyceps cicadae on phytohemagglutinin (PHA)-stimulated cell proliferation were studied in primary human T cells. The results showed that Cpd 6A suppressed T-cell proliferation for about 24 h after stimulation with PHA. Cell cycle analysis indicated that Cpd 6A arrested the cell cycle progression of activated T cells from the G1 transition to the S phase. To localize the point in the cell cycle where arrest occurred, a set of key regulatory events leading to the G1/S boundary, including the expression of cyclins D2, E, A1, and B1, interleukin (IL)-2, IL-4, interferon-gamma (IFN-gamma), and activating protein-1 (AP-1), was examined. Cpd 6A suppressed, in activated T lymphocytes, the production and mRNA expression of cyclin E, IL-2, IL-4, IL-10, and IFN-gamma in a dose-dependent manner. Expression of AP-1 proteins, consisting of c-Fos and c-Jun, in activated T lymphocytes was decreased by Cpd 6A. The kinetic study indicated that the inhibitory effects of Cpd 6A on IL-2 mRNA expressed in T cells might be related to blocking c-Fos protein synthesis. T-cell proliferation after Cpd 6A treatment was partially restored by addition of IL-2, IL-4, and IFN-gamma. These suppressant effects of Cpd 6A on T-cell proliferation, activated by PHA, appeared to be mediated, at least in part, through the inhibition of early gene transcripts, especially those of cyclin E, IFN-gamma, IL-2, and IL-4, and by arresting cell cycle progression in the cells.
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Affiliation(s)
- Y C Kuo
- Institute of Life Science, Fu-Jen University, Taipei, Taiwan, ROC
- National Research Institute of Chinese Medicine, Taipei, Taiwan, ROC
| | - S C Weng
- Institute of Life Science, Fu-Jen University, Taipei, Taiwan, ROC
| | - C J Chou
- National Research Institute of Chinese Medicine, Taipei, Taiwan, ROC
| | - T T Chang
- Division of Forest Protection, Taiwan Forest Research Institute, Taipei, Taiwan, ROC
| | - W J Tsai
- National Research Institute of Chinese Medicine, Taipei, Taiwan, ROC
- Author for correspondence:
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Hung KS, Hong CY, Lee J, Lin SK, Huang SC, Wang TM, Tse V, Sliverberg GD, Weng SC, Hsiao M. Expression of p16(INK4A) induces dominant suppression of glioblastoma growth in situ through necrosis and cell cycle arrest. Biochem Biophys Res Commun 2000; 269:718-25. [PMID: 10720483 DOI: 10.1006/bbrc.2000.2339] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tumor suppressor genes may represent an important new therapeutic modality in the treatment of human glioblastoma (GBM). p16(INK4A) is a tumor suppressor gene with mutation and/or deletion found in many human tumors, including glioblastomas, melanoma, and leukemias. RT-2 rat GBM cell line was used to investigate if the p16 gene induces dominant suppression of glioblastoma growth. Close to 100% of tumor cells were infected by high titer pCL retrovirus encoding the full-length human p16 cDNA at 5 m.o.i. Infected cells showed a 98% reduction in colony forming assay and a 60% reduction in growth curves in vitro compared to vector control. Exogenous overexpression of p16 induced hypophosphorylation of Rb protein by Western blot analysis. Intracranial injection of p16-infected tumor cells into syngeneic rats resulted in a 95% reduction in tumor volume compared to the controls. Intratumoral injection of p16 retrovirus resulted in tumor necrosis and prominent human p16 transgene expressions. Proliferation marker PCNA was not detected in these human p16-expressed RT-2 tumor cells, suggesting the cells were unable to enter into S phase after p16 expression. In addition, direct repeat intracranial injections of p16 retrovirus prolonged animal survival 3.2-fold compared to the controls (48.4 +/- 13.4 vs 15.0 +/- 2.1 days, p < 0.001). Two out of ten rats were found with dormant tumors at day 60 after p16 retrovirus injection. These results showed that p16 is effective in inhibiting GBM growth in situ. The mechanisms of tumor growth reduction and necrosis in vivo might be due to G1 arrest triggered by p16 expression.
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Affiliation(s)
- K S Hung
- Department of Neurosurgery, Chang-Gung Memorial Hospital, Kaohsiung, Taipei, Taiwan, Republic of China
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Hwang HM, Weng SC, Lo SK, Yu RK, Tsai WH. Neuritogenesis, not receptor expression, of NG108-15 cells can be modulated by monosialoganglioside GM1. CHINESE J PHYSIOL 1996; 39:211-7. [PMID: 9058005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In this study, involvement of gangliosides in neurite outgrowth and receptor expression of the neuroblastoma X glioma hybrid NG108-15 cloned cells was investigated. Monosialoganglioside GM1 (100 microM) and disialoganglioside GD1a (100 microM) were applied to the culture medium at different concentrations of fetal bovine serum, 1-10%, with or without addition of dibutyryl adenosine 3',5'-cyclic monophosphate (500 microM). In some experiments, 5 mg/ml of cholera toxin B was added to the media to block endogenous GM1. The results indicated that GM1 had an influence on cell proliferation and neuritogenesis but did not induce muscarinic receptor expression of NG108-15 cells.
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Affiliation(s)
- H M Hwang
- Department of Anatomy, Chang Gung College of Medicine & Technology, Kwei-San, Taoyuan, Taiwan, ROC
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