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Park DS, Wang H, Vasheghani Farahani SK, Walker M, Bhatnagar A, Seghier D, Choi CJ, Kang JH, McConville CF. Surface passivation of semiconducting oxides by self-assembled nanoparticles. Sci Rep 2016; 6:18449. [PMID: 26757827 PMCID: PMC4725940 DOI: 10.1038/srep18449] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/12/2015] [Indexed: 11/13/2022] Open
Abstract
Physiochemical interactions which occur at the surfaces of oxide materials can significantly impair their performance in many device applications. As a result, surface passivation of oxide materials has been attempted via several deposition methods and with a number of different inert materials. Here, we demonstrate a novel approach to passivate the surface of a versatile semiconducting oxide, zinc oxide (ZnO), evoking a self-assembly methodology. This is achieved via thermodynamic phase transformation, to passivate the surface of ZnO thin films with BeO nanoparticles. Our unique approach involves the use of BexZn1-xO (BZO) alloy as a starting material that ultimately yields the required coverage of secondary phase BeO nanoparticles, and prevents thermally-induced lattice dissociation and defect-mediated chemisorption, which are undesirable features observed at the surface of undoped ZnO. This approach to surface passivation will allow the use of semiconducting oxides in a variety of different electronic applications, while maintaining the inherent properties of the materials.
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Affiliation(s)
- Dae-Sung Park
- Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Haiyuan Wang
- Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | | | - Marc Walker
- Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Akash Bhatnagar
- Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Djelloul Seghier
- Science Institute, University of Iceland, Dunhaga 3, Reykjavik, IS-107, Iceland
| | - Chel-Jong Choi
- School of Semiconductor and Chemical Engineering, Chonbuk National University, Jeonju, 561-756, Republic of Korea
| | - Jie-Hun Kang
- Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom.,Department of Nano and Electronic Physics, Kookmin University, Seoul, 136-702, Republic of Korea
| | - Chris F McConville
- Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom
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Abstract
Transmission electron microscopy offers structural and compositional information with atomic resolution, but its use is restricted to thin, solid samples. Liquid samples, particularly those involving water, have been challenging because of the need to form a thin liquid layer that is stable within the microscope vacuum. Liquid cell electron microscopy is a developing technique that allows us to apply the powerful capabilities of the electron microscope to imaging and analysis of liquid specimens. We describe its impact in materials science and biology. We discuss how its applications have expanded via improvements in equipment and experimental techniques, enabling new capabilities and stimuli for samples in liquids, and offering the potential to solve grand challenge problems.
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Affiliation(s)
- Frances M Ross
- IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598, USA.
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53
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Zhou Y, Rui X, Sun W, Xu Z, Zhou Y, Ng WJ, Yan Q, Fong E. Biochemistry-Enabled 3D Foams for Ultrafast Battery Cathodes. ACS NANO 2015; 9:4628-4635. [PMID: 25858505 DOI: 10.1021/acsnano.5b00932] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Metal vanadium phosphates (MVP), particularly Li3V2(PO4)3 (LVP) and Na3V2(PO4)3 (NVP), are regarded as the next-generation cathode materials in lithium/sodium ion batteries. These materials possess desirable properties such as high stability, theoretical capacity, and operating voltages. Yet, low electrical/ionic conductivities of LVP and NVP have limited their applications in demanding devices such as electric vehicles. In this work, a novel synthesis route for the preparation of LVP/NVP micro/mesoporous 3D foams via assembly of elastin-like polypeptides is demonstrated. The as-synthesized MVP 3D foams consist of microporous networks of mesoporous nanofibers, where the surfaces of individual fibers are covered with MVP nanocrystallites. TEM images further reveal that LVP/NVP nanoparticles are about 100-200 nm in diameter, with each particle enveloped by a 5 nm thick carbon shell. The MVP 3D foams prepared in this work exhibit ultrafast rate capabilities (79 mA h g(-1) at 100C and 66 mA h g(-1) at 200C for LVP 3D foams; 73 mA h g(-1) at 100C and 51 mA h g(-1) at 200C for NVP 3D foams) and excellent cycle performance (almost 100% performance retention after 1000 cycles at 100C); their properties are far superior compared to current state-of-the-art active materials.
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Affiliation(s)
- Yanping Zhou
- §Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 CleanTech Loop, 637141, Singapore
| | - Xianhong Rui
- †School of Energy and Environment, Anhui University of Technology, Maanshan, Anhui 243002, China
| | | | | | - Yan Zhou
- §Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 CleanTech Loop, 637141, Singapore
| | - Wun Jern Ng
- §Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 CleanTech Loop, 637141, Singapore
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Zhang H, Liu X, Feng S, Wang W, Schmidt-Rohr K, Akinc M, Nilsen-Hamilton M, Vaknin D, Mallapragada S. Morphological transformations in the magnetite biomineralizing protein Mms6 in iron solutions: a small-angle X-ray scattering study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2818-2825. [PMID: 25669122 DOI: 10.1021/la5044377] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Magnetotactic bacteria that produce magnetic nanocrystals of uniform size and well-defined morphologies have inspired the use of biomineralization protein Mms6 to promote formation of uniform magnetic nanocrystals in vitro. Small angle X-ray scattering (SAXS) studies in physiological solutions reveal that Mms6 forms compact globular three-dimensional (3D) micelles (approximately 10 nm in diameter) that are, to a large extent, independent of concentration. In the presence of iron ions in the solutions, the general micellar morphology is preserved, however, with associations among micelles that are induced by iron ions. Compared with Mms6, the m2Mms6 mutant (with the sequence of hydroxyl/carboxyl containing residues in the C-terminal domain shuffled) exhibits subtle morphological changes in the presence of iron ions in solutions. The analysis of the SAXS data is consistent with a hierarchical core-corona micellar structure similar to that found in amphiphilic polymers. The addition of ferric and ferrous iron ions to the protein solution induces morphological changes in the micellar structure by transforming the 3D micelles into objects of reduced dimensionality of 2, with fractal-like characteristics (including Gaussian-chain-like) or, alternatively, platelet-like structures.
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Affiliation(s)
- Honghu Zhang
- Division of Materials Science and Engineering, Ames Laboratory, USDOE , Ames, Iowa 50011, United States
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55
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Shahlori R, Waterhouse GIN, Nelson ARJ, McGillivray DJ. Morphological, chemical and kinetic characterisation of zein protein-induced biomimetic calcium phosphate films. J Mater Chem B 2015; 3:6213-6223. [DOI: 10.1039/c5tb00702j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A zein protein layer was used to mineralize thin films of calcium phosphate at the air–solution interface producing an iridescent mineral film with novel nano-morphology.
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Affiliation(s)
- Rayomand Shahlori
- School of Chemical Sciences
- University of Auckland
- Auckland 1142
- New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology
| | - Geoffrey I. N. Waterhouse
- School of Chemical Sciences
- University of Auckland
- Auckland 1142
- New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology
| | - Andrew R. J. Nelson
- Bragg Institute
- Australian Nuclear Science and Technology Organisation
- Australia
| | - Duncan J. McGillivray
- School of Chemical Sciences
- University of Auckland
- Auckland 1142
- New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology
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56
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Woehl TJ, Kashyap S, Firlar E, Perez-Gonzalez T, Faivre D, Trubitsyn D, Bazylinski DA, Prozorov T. Correlative electron and fluorescence microscopy of magnetotactic bacteria in liquid: toward in vivo imaging. Sci Rep 2014; 4:6854. [PMID: 25358460 PMCID: PMC4215306 DOI: 10.1038/srep06854] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 10/10/2014] [Indexed: 12/05/2022] Open
Abstract
Magnetotactic bacteria biomineralize ordered chains of uniform, membrane-bound magnetite or greigite nanocrystals that exhibit nearly perfect crystal structures and species-specific morphologies. Transmission electron microscopy (TEM) is a critical technique for providing information regarding the organization of cellular and magnetite structures in these microorganisms. However, conventional TEM can only be used to image air-dried or vitrified bacteria removed from their natural environment. Here we present a correlative scanning TEM (STEM) and fluorescence microscopy technique for imaging viable cells of Magnetospirillum magneticum strain AMB-1 in liquid using an in situ fluid cell TEM holder. Fluorescently labeled cells were immobilized on microchip window surfaces and visualized in a fluid cell with STEM, followed by correlative fluorescence imaging to verify their membrane integrity. Notably, the post-STEM fluorescence imaging indicated that the bacterial cell wall membrane did not sustain radiation damage during STEM imaging at low electron dose conditions. We investigated the effects of radiation damage and sample preparation on the bacteria viability and found that approximately 50% of the bacterial membranes remained intact after an hour in the fluid cell, decreasing to ~30% after two hours. These results represent a first step toward in vivo studies of magnetite biomineralization in magnetotactic bacteria.
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Affiliation(s)
- Taylor J. Woehl
- Emergent Atomic and Magnetic Structures, Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA 50011, USA
| | - Sanjay Kashyap
- Emergent Atomic and Magnetic Structures, Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA 50011, USA
| | - Emre Firlar
- Emergent Atomic and Magnetic Structures, Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA 50011, USA
| | - Teresa Perez-Gonzalez
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Damien Faivre
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Denis Trubitsyn
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV 89154, USA
| | - Dennis A. Bazylinski
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV 89154, USA
| | - Tanya Prozorov
- Emergent Atomic and Magnetic Structures, Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA 50011, USA
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