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Armelao L, Heigl F, Brunet S, Sammynaiken R, Regier T, Blyth RIR, Zuin L, Sankari R, Vogt J, Sham T. The Origin and Dynamics of Soft X‐Ray‐Excited Optical Luminescence of ZnO. Chemphyschem 2010; 11:3625-31. [DOI: 10.1002/cphc.201000730] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lidia Armelao
- Department of Chemistry, ISTM‐CNR and INSTM, University of Padova, Via Marzolo 1, 35131 Padova (Italy), Fax: (+39) 049 827 5227
- Department of Chemistry, University of Western Ontario, 1151 Richmond Street, London N6 A 5B7 (Canada), Fax: (+1) 519 661 3022
| | - Franziskus Heigl
- Department of Chemistry, University of Western Ontario, 1151 Richmond Street, London N6 A 5B7 (Canada), Fax: (+1) 519 661 3022
| | - Sophie Brunet
- Saskatchewan Structural Science Center, University of Saskatchewan, 116 Science Place, Saskatoon S7N 5E2 (Canada)
| | - Ramaswami Sammynaiken
- Saskatchewan Structural Science Center, University of Saskatchewan, 116 Science Place, Saskatoon S7N 5E2 (Canada)
| | - Tom Regier
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Robert I. R. Blyth
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Lucia Zuin
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Rami Sankari
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Johannes Vogt
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Tsun‐Kong Sham
- Department of Chemistry, University of Western Ontario, 1151 Richmond Street, London N6 A 5B7 (Canada), Fax: (+1) 519 661 3022
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Heigl F, Armelao L, Sun XHJ, Didychuk C, Zhou XT, Regier T, Blyth RIR, Kim PSG, Rosenberg RA, Sham TK. XANES and photoluminescence studies of crystalline GeO2(Tb) nanowires. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/190/1/012130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Gillespie AW, Walley FL, Farrell RE, Regier TZ, Blyth RIR. Calibration method at the N K-edge using interstitial nitrogen gas in solid-state nitrogen-containing inorganic compounds. J Synchrotron Radiat 2008; 15:532-534. [PMID: 18728328 DOI: 10.1107/s0909049508014283] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 05/12/2008] [Indexed: 05/26/2023]
Abstract
The standard method of soft X-ray beamline calibration at the N K-edge uses the nu = 0 peak transition of gas-phase N(2). Interstitial N(2) gas trapped or formed within widely available solid-state ammonium- and amine-containing salts can be used for this purpose, bypassing gas-phase measurements. Evidence from non-nitrogen-containing compounds (KH(2)PO(4)) and from He-purged ammonium salts suggest that production of N(2) gas is through beam-induced decomposition. Compounds with nitrate or nitrite as anions produce coincident features and are not suitable for this calibration method.
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Affiliation(s)
- Adam W Gillespie
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5A8.
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Arima V, Blyth RIR, Matino F, Chiodo L, Della Sala F, Thompson J, Regier T, Del Sole R, Mele G, Vasapollo G, Cingolani R, Rinaldi R. Zinc porphyrin-driven assembly of gold nanofingers. Small 2008; 4:497-506. [PMID: 18348225 DOI: 10.1002/smll.200700276] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nanofingers of gold covered by porphyrins are prepared by a combination of atomic manipulation and surface self-organization. A submonolayer of zinc(II) 5,10,15,20-tetrakis(4-tert-butylphenyl)-porphyrin (ZnTBPP) axially ligated to a self-assembled monolayer of 4-aminothiophenol (4-ATP) on Au(111) is prepared and studied using a combination of ultrahigh vacuum techniques. Under the electric field produced by the STM tip, the relatively weakly bound Au surface atoms along the discommensuration lines become mobile due to the strong bond to 4-ATP, while the tendency of the porphyrins towards self-assembly result in a collective motion of gold clusters. The clusters diffuse onto the surface following well-defined pathways along the [112] direction and then reach the step edges where they assembled, thus forming nanofingers. First-principles density functional theory calculations demonstrate the reduction of the binding energies between the surface gold clusters and the substrate induced by adsorption of thiols. Scanning tunneling microscopy images show assemblies across three adjacent discommensuration lines of the Au(111)-(22 x square root 3) reconstruction, which collectively diffuse along these lines to form islands nucleated at step edges.
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Affiliation(s)
- Valentina Arima
- National Nanotechnology Laboratory (CNR-INFM), Distretto Tecnologico ISUFI, Università degli studi di Lecce ,via Arnesano, 73100 Lecce, Italy.
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Leinweber P, Kruse J, Walley FL, Gillespie A, Eckhardt KU, Blyth RIR, Regier T. Nitrogen K-edge XANES - an overview of reference compounds used to identify unknown organic nitrogen in environmental samples. J Synchrotron Radiat 2007; 14:500-511. [PMID: 17960033 DOI: 10.1107/s0909049507042513] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Accepted: 08/30/2007] [Indexed: 05/25/2023]
Abstract
The chemical nature of soil organic nitrogen (N) is still poorly understood and one-third to one-half of it is typically classified as ;unknown N'. Nitrogen K-edge XANES spectroscopy has been used to develop a systematic overview on spectral features of all major N functions in soil and environmental samples. The absolute calibration of the photon energy was completed using the 1s --> pi* transitions of pure gas-phase N(2). On this basis a library of spectral features is provided for mineral N, nitro N, amino acids, peptides, and substituted pyrroles, pyridines, imidazoles, pyrazoles, pyrazines, pyrimidines and purine bases. Although N XANES was previously considered ;non-destructive', effects of radiation damage were shown for two compound classes and an approach was proposed to minimize it. This new evidence is integrated into a proposal for the evaluation spectra from environmental samples with unknown composition. Thus a basis is laid to develop N K-edge XANES as a complementary standard research method to study the molecular composition and ecological functions of ;unknown N' in soil and the environment.
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Affiliation(s)
- Peter Leinweber
- Institute for Land Use, University of Rostock, Justus von Liebig Weg 6, 18057 Rostock, Germany.
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Zhou X, Sham TK, Wu Y, Chong YM, Bello I, Lee ST, Heigl F, Regier T, Blyth RIR. X-ray Excited Optical Luminescence from Diamond Thin Films: The Contribution of sp2- and H-Bonded Carbon to the Luminescence. J Am Chem Soc 2007; 129:1476-7. [PMID: 17249664 DOI: 10.1021/ja064555r] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xingtai Zhou
- Department of Chemistry, The University of Western Ontario, London, Canada N6A 5B7
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Maiorano V, Matino F, Cingolani R, Thompson J, Blyth RIR. X-ray excited visible luminescence spectroscopy of organic materials using a portable optical spectrometer. J Synchrotron Radiat 2005; 12:690-5. [PMID: 16120997 DOI: 10.1107/s090904950501931x] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Accepted: 06/17/2005] [Indexed: 05/04/2023]
Abstract
The use of a portable video telescope, mounted externally to a beamline endstation, to obtain synchrotron-radiation-excited visible luminescence, is described. Real-time video monitoring permits simple and quick alignment, and allows a visual record of the luminescence experiment. The telescope is fibre-optic-coupled to an optical spectrometer. Examples are given of X-ray excited optical spectroscopy from organic materials for light-emitting-diode applications.
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Affiliation(s)
- Vincenzo Maiorano
- National Nanotechnology Laboratory of INFM, Distretto Technologico della Università di Lecce, via Arnesano, 73100 Lecce, Italy
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Arima V, Fabiano E, Blyth RIR, Della Sala F, Matino F, Thompson J, Cingolani R, Rinaldi R. Self-Assembled Monolayers of Cobalt(II)− (4-tert-Butylphenyl)-Porphyrins: The Influence of the Electronic Dipole on Scanning Tunneling Microscopy Images. J Am Chem Soc 2004; 126:16951-8. [PMID: 15612733 DOI: 10.1021/ja0470970] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [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
Self-assembled monolayers (SAMs) of cobalt(II) 5,10,15,20-tetrakis(4-tert-butylphenyl)-porphyrin, a promising material for optical, photoelectrochemical, and chemical sensor applications, were prepared on Au(111) via axial ligation to 4-aminothiophenol, and studied by several surface science techniques. Scanning tunneling microscopy (STM) and spectroscopy (STS) measurements showed the apparent topology of the Au(111) herringbone structure reconstruction, but with bias-dependent contrast images and asymmetric I/V characteristics. Photoelectron spectroscopy confirmed the presence of metalloporphyrins on the surface, whereas near-edge X-ray absorption (NEXAFS) measurements revealed that the porphyrin ring was tilted by about 70 degrees with respect to the surface plane. The above effects are ascribed to the presence of oriented molecular dipole layers between the metal and the organic material as confirmed by a comparison with first-principles density-functional theory calculations. The measured bias-dependent STM profiles have been reproduced by a simple monodimensional tunneling model.
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Affiliation(s)
- Valentina Arima
- National Nanotechnology Laboratory of INFM, Distretto Tecnologico ISUFI, Università di Lecce, Via Arnesano, 73100 Lecce, Italy.
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Blyth RIR, Duschek R, Koller G, Netzer FP, Ramsey MG. Thin Films and Interfaces of Electroactive Organic Materials: The Surface Science Approach. Monatshefte fuer Chemie/Chemical Monthly 2001. [DOI: 10.1007/s007060170113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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