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Al-Saadi MJ, Al-Harthi SH, Kyaw HH, Myint MT, Bora T, Laxman K, Al-Hinai A, Dutta J. Influence of Atomic Hydrogen, Band Bending, and Defects in the Top Few Nanometers of Hydrothermally Prepared Zinc Oxide Nanorods. NANOSCALE RESEARCH LETTERS 2017; 12:22. [PMID: 28063141 PMCID: PMC5218952 DOI: 10.1186/s11671-016-1800-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 11/28/2016] [Indexed: 05/22/2023]
Abstract
We report on the surface, sub-surface (top few nanometers) and bulk properties of hydrothermally grown zinc oxide (ZnO) nanorods (NRs) prior to and after hydrogen treatment. Upon treating with atomic hydrogen (H*), upward and downward band bending is observed depending on the availability of molecular H2O within the structure of the NRs. In the absence of H2O, the H* treatment demonstrated a cleaning effect of the nanorods, leading to a 0.51 eV upward band bending. In addition, enhancement in the intensity of room temperature photoluminescence (PL) signals due to the creation of new surface defects could be observed. The defects enhanced the visible light activity of the ZnO NRs which were subsequently used to photocatalytically degrade aqueous phenol under simulated sunlight. On the contrary, in the presence of H2O, H* treatment created an electronic accumulation layer inducing downward band bending of 0.45 eV (~1/7th of the bulk ZnO band gap) along with the weakening of the defect signals as observed from room temperature photoluminescence spectra. The results suggest a plausible way of tailoring the band bending and defects of the ZnO NRs through control of H2O/H* species.
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Affiliation(s)
- Mubarak J. Al-Saadi
- Department of Physics, Sultan Qaboos University, PO Box 36, Al Khoudh, 123, Muscat, Oman
| | - Salim H. Al-Harthi
- Department of Physics, Sultan Qaboos University, PO Box 36, Al Khoudh, 123, Muscat, Oman
| | - Htet H. Kyaw
- Department of Physics, Sultan Qaboos University, PO Box 36, Al Khoudh, 123, Muscat, Oman
| | - Myo T.Z. Myint
- Department of Physics, Sultan Qaboos University, PO Box 36, Al Khoudh, 123, Muscat, Oman
| | - Tanujjal Bora
- Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, PO Box 17 Al Khoudh, 123, Muscat, Oman
| | - Karthik Laxman
- Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, PO Box 17 Al Khoudh, 123, Muscat, Oman
| | - Ashraf Al-Hinai
- Department of Chemistry, Sultan Qaboos University, PO Box 36, Al Khoudh, 123, Muscat, Oman
| | - Joydeep Dutta
- Functional Materials Division, Materials and Nanophysics, ICT School, KTH Royal Institute of Technology, Isafjordsgatan 22, SE-164 40 Kista, Stockholm Sweden
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Blumenstein NJ, Streb F, Walheim S, Schimmel T, Burghard Z, Bill J. Template-controlled piezoactivity of ZnO thin films grown via a bioinspired approach. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:296-303. [PMID: 28243568 PMCID: PMC5301953 DOI: 10.3762/bjnano.8.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 01/08/2017] [Indexed: 05/09/2023]
Abstract
Biomaterials are used as model systems for the deposition of functional inorganic materials under mild reaction conditions where organic templates direct the deposition process. In this study, this principle was adapted for the formation of piezoelectric ZnO thin films. The influence of two different organic templates (namely, a carboxylate-terminated self-assembled monolayer and a sulfonate-terminated polyelectrolyte multilayer) on the deposition and therefore on the piezoelectric performance was investigated. While the low negative charge of the COOH-SAM is not able to support oriented attachment of the particles, the strongly negatively charged sulfonated polyelectrolyte leads to texturing of the ZnO film. This texture enables a piezoelectric performance of the material which was measured by piezoresponse force microscopy. This study shows that it is possible to tune the piezoelectric properties of ZnO by applying templates with different functionalities.
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Affiliation(s)
- Nina J Blumenstein
- Institute for Materials Science, University of Stuttgart, Heisenbergstraße 3, Stuttgart, D-70569, Germany
| | - Fabian Streb
- Institute for Materials Science, University of Stuttgart, Heisenbergstraße 3, Stuttgart, D-70569, Germany
| | - Stefan Walheim
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, D-76344, Germany
- Institute of Applied Physics and Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1, Karlsruhe, D-76131, Germany
| | - Thomas Schimmel
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, D-76344, Germany
- Institute of Applied Physics and Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1, Karlsruhe, D-76131, Germany
| | - Zaklina Burghard
- Institute for Materials Science, University of Stuttgart, Heisenbergstraße 3, Stuttgart, D-70569, Germany
| | - Joachim Bill
- Institute for Materials Science, University of Stuttgart, Heisenbergstraße 3, Stuttgart, D-70569, Germany
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Blumenstein NJ, Hofmeister CG, Lindemann P, Huang C, Baier J, Leineweber A, Walheim S, Wöll C, Schimmel T, Bill J. Chemical bath deposition of textured and compact zinc oxide thin films on vinyl-terminated polystyrene brushes. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:102-10. [PMID: 26925358 PMCID: PMC4734420 DOI: 10.3762/bjnano.7.12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 01/06/2016] [Indexed: 05/24/2023]
Abstract
In this study we investigated the influence of an organic polystyrene brush on the deposition of ZnO thin films under moderate conditions. On a non-modified SiO x surface, island growth is observed, whereas the polymer brush induces homogeneous film growth. A chemical modification of the polystyrene brushes during the mineralization process occurs, which enables stronger interaction between the then polar template and polar ZnO crystallites in solution. This may lead to oriented attachment of the crystallites so that the observed (002) texture arises. Characterization of the templates and the resulting ZnO films were performed with ζ-potential and contact angle measurements as well as scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). Infrared spectroscopy (IR) measurements were used to investigate the polystyrene brushes before and after modification.
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Affiliation(s)
- Nina J Blumenstein
- Institute for Materials Science, University of Stuttgart, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | - Caroline G Hofmeister
- Institute for Materials Science, University of Stuttgart, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | - Peter Lindemann
- Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Cheng Huang
- Institute of Applied Physics and Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1, D-76131 Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Johannes Baier
- Institute for Materials Science, University of Stuttgart, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | - Andreas Leineweber
- Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
| | - Stefan Walheim
- Institute of Applied Physics and Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1, D-76131 Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Christof Wöll
- Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Thomas Schimmel
- Institute of Applied Physics and Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1, D-76131 Karlsruhe, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Joachim Bill
- Institute for Materials Science, University of Stuttgart, Heisenbergstrasse 3, D-70569 Stuttgart, Germany
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