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Evaluating the plasmon-exciton interaction in ZnO tetrapods coupled with gold nanostructures by nanoscale cathodoluminescence. NANO EXPRESS 2021. [DOI: 10.1088/2632-959x/abe277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Abstract
Plasmon-exciton coupling is gaining increasing interest for enhancing the performance of optoelectronic, photonic and photo-catalytic devices. Herein we evaluate the interaction of excitons in zinc oxide tetrapods with surface plasmons of gold nanostructures with different morphologies. The gold nanostructures are grown in situ on ZnO tetrapods by means of a photochemical process, resulting in clean interfaces. The modification of the synthesis parameters results in different morphologies, as isolated nanoparticles, nano-domes or nanoparticles aggregates. Plasmon-exciton interaction is evaluated by means of cathodoluminescence spectroscopy and mapping at the nanoscale. The ZnO excitonic emission is strongly blue-shifted and broadened in close proximity of the gold nanostructures. This effect is explained by the formation of a Schottky barrier that is strongly mediated by the morphology of metal nanostructures.
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Transforming diatomaceous earth into sensing devices by surface modification with gold nanoparticles. MICRO AND NANO ENGINEERING 2019. [DOI: 10.1016/j.mne.2018.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Functionalization of carbon fiber tows with ZnO nanorods for stress sensor integration in smart composite materials. NANOTECHNOLOGY 2018; 29:335501. [PMID: 29808831 DOI: 10.1088/1361-6528/aac850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The physical and operating principle of a stress sensor, based on two crossing carbon fibers functionalized with ZnO nanorod-shaped nanostructures, was recently demonstrated. The functionalization process has been here extended to tows made of one thousand fibers, like those commonly used in industrial processing, to prove the idea that the same working principle can be exploited in the creation of smart sensing carbon fiber composites. A stress-sensing device made of two functionalized tows, fixed with epoxy resin and crossing like in a typical carbon fiber texture, was successfully tested. Piezoelectric properties of single nanorods, as well as those of the test device, were measured and discussed.
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Silica diatom shells tailored with Au nanoparticles enable sensitive analysis of molecules for biological, safety and environment applications. NANOSCALE RESEARCH LETTERS 2018; 13:94. [PMID: 29633086 PMCID: PMC5891442 DOI: 10.1186/s11671-018-2507-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 03/28/2018] [Indexed: 05/08/2023]
Abstract
Diatom shells are a natural, theoretically unlimited material composed of silicon dioxide, with regular patterns of pores penetrating through their surface. For their characteristics, diatom shells show promise to be used as low cost, highly efficient drug carriers, sensor devices or other micro-devices. Here, we demonstrate diatom shells functionalized with gold nanoparticles for the harvesting and detection of biological analytes (bovine serum albumin-BSA) and chemical pollutants (mineral oil) in low abundance ranges, for applications in bioengineering, medicine, safety, and pollution monitoring.
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Charge-separation enhancement in inverted polymer solar cells by molecular-level triple heterojunction: NiO-np:P3HT:PCBM. NANOTECHNOLOGY 2017; 28:035403. [PMID: 27966476 DOI: 10.1088/1361-6528/28/3/035403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hole collection and transport are crucial physical processes in bulk-heterojunction (BHJ) solar cells, which represent major bottlenecks due to their limitations in power conversion efficiency (PCE). Hence, a more efficient alternative is needed to accept and transport holes to the collection electrode in BHJ solar cells. Here, we bring both electron and hole collection centres close to the point of exciton generation by infiltrating P3HT poly(3-hexylthiophene):PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) blend into a highly porous interconnected p-type NiO-nanoparticle (NiO-np) network, through solvent-assisted grafting. In this study, a hybrid polymer solar cell is demonstrated with a P3HT:PCBM:NiO-np triple-heterojunction active layer which showed greatly improved rectification behaviour, long electron lifetime and generated higher PCE of 4% under AM 1.5 solar illumination with a 75% increase in PCE with respect to the P3HT:PCBM device. The optimum NiO-np amount and active-layer thickness were found to be 2% and 250 nm, respectively.
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A new method to integrate ZnO nano-tetrapods on MEMS micro-hotplates for large scale gas sensor production. NANOTECHNOLOGY 2016; 27:385503. [PMID: 27532770 DOI: 10.1088/0957-4484/27/38/385503] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A new method, which is easily scalable to large scale production, has been developed to obtain gas sensor devices based on zinc oxide (ZnO) nanostructures with a 'tetrapod' shape. The method can be easily extended to other kinds of nanostructures and is based on the deposition of ZnO nanostructures through polymeric masks by centrifugation, directly onto properly designed MEMS micro-hotplates. The micromachined devices, after the mask is peeled off, are ready for electrical bonding and sensing test. Sensor response has been successfully measured for some gases and volatile organic compounds with different chemical properties (ethanol, methane, nitrogen dioxide, hydrogen sulfide).
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Abstract
We present a new 3D surface-enhanced Raman spectroscopy substrate made of branched gold nanoparticles supported on ZnO tetrapods that was proved to be effective in different biomedical application such as drug detection and cancer cells analysis.
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Selective response inversion to NO₂ and acetic acid in ZnO and CdS nanocomposite gas sensor. NANOTECHNOLOGY 2014; 25:365502. [PMID: 25121359 DOI: 10.1088/0957-4484/25/36/365502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
High sensitivity zinc oxide (ZnO) tetrapods (TPs) have been functionalized by nucleating cadmium sulphide (CdS) nanoparticles (NPs) directly on their surface with a spotted coverage thanks to an optimized synthesis in dimethylformamide (DMF). The obtained hybrid coupled material has been used to realize a gas sensing device with a highly porous nanostructured network, in which the proper alternation of ZnO-TPs and CdS-NPs gives rise to unconventional chemoresistive behaviours. Among the different tested gases and vapours, the sensor showed a unique fingerprint response-inversion between 300 °C and 400 °C only for nitrogen dioxide (NO2) and acetic acid (CH3COOH).
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Electroless gold patterning of CdZnTe crystals for radiation detection by scanning pipette technique. CRYSTAL RESEARCH AND TECHNOLOGY 2014. [DOI: 10.1002/crat.201300415] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Facile synthesis of hierarchical CuO nanostructures with enhanced photocatalytic activity. CRYSTAL RESEARCH AND TECHNOLOGY 2014. [DOI: 10.1002/crat.201300409] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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11
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Zn vacancy induced green luminescence on non-polar surfaces in ZnO nanostructures. Sci Rep 2014; 4:5158. [PMID: 24894901 PMCID: PMC5154428 DOI: 10.1038/srep05158] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 05/09/2014] [Indexed: 12/22/2022] Open
Abstract
Although generally ascribed to the presence of defects, an ultimate assignment of the different contributions to the emission spectrum in terms of surface states and deep levels in ZnO nanostructures is still lacking. In this work we unambiguously give first evidence that zinc vacancies at the (1010) nonpolar surfaces are responsible for the green luminescence of ZnO nanostructures. The result is obtained by performing an exhaustive comparison between spatially resolved cathodoluminescence spectroscopy and imaging and ab initio simulations. Our findings are crucial to control undesired recombinations in nanostructured devices.
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Oriented orthorhombic Lead Oxide film grown by vapour phase deposition for X-ray detector applications. CRYSTAL RESEARCH AND TECHNOLOGY 2013. [DOI: 10.1002/crat.201300022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Composite multifunctional nanostructures based on ZnO tetrapods and superparamagnetic Fe3O4 nanoparticles. NANOTECHNOLOGY 2013; 24:135601. [PMID: 23478269 DOI: 10.1088/0957-4484/24/13/135601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A nanocomposite material is obtained by coupling superparamagnetic magnetite nanoparticles (Fe3O4 NP) and vapor phase grown zinc oxide nanostructures with 'tetrapod' morphology (ZnO TP). The aim is the creation of a multifunctional material which retains the attractive features of ZnO (e.g. surface reactivity, strong UV emission, piezoelectricity) together with added magnetism. Structural, morphological, optical, magnetic and functional characterization are performed. In particular, the high saturation magnetization of Fe3O4 NP (above 50 A m(2) kg(-1)), the strong UV luminescence and the enhanced photocatalytic activity of coupled nanostructures are discussed. Thus the nanocomposite turns out to be suitable for applications in energy harvesting and conversion, gas- and bio-sensing, bio-medicine and filter-free photocatalysis.
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Solution-free and catalyst-free synthesis of ZnO-based nanostructured TCOs by PED and vapor phase growth techniques. NANOTECHNOLOGY 2012; 23:194008. [PMID: 22539075 DOI: 10.1088/0957-4484/23/19/194008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Zinc oxide (ZnO) is one of the most promising materials for realizing three-dimensional (3D) nanostructured transparent conducting oxides (TCOs) on large scale, because it is cheap, it can be modified with large concentrations of trivalent elements (such Al, Ga or In) and it is characterized by good electron mobility, wide bandgap and visible-range transparency. But, above all, it can be easily obtained in the form of different nanostructures with a large number of growth techniques. A solution-free and catalyst-free approach has been explored here by the vapor phase synthesis of vertically aligned ZnO nanorods on ZnO:Al (AZO) films grown by pulsed electron deposition (PED). The obtained nanostructured TCOs resulted to be homogeneous on large areas and easily patternable by means of mechanical masks. The morphology, crystalline structure, electrical and optical properties of the obtained samples have been characterized in depth. The possible use of such a nanostructured TCO in excitonic (e.g. DSSC) or low-reflectivity traditional solar cells is discussed.
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Functionalized ZnO nanostructures for gas sensing and photovoltaic applications. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311086454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Development of a combined SEM and ICP-MS approach for the qualitative and quantitative analyses of metal nano and microparticles in food products [corrected]. Anal Bioanal Chem 2011; 401:1401-9. [PMID: 21660413 DOI: 10.1007/s00216-011-5149-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 05/23/2011] [Accepted: 05/26/2011] [Indexed: 11/30/2022]
Abstract
An integrated approach based on the use of inductively coupled plasma mass spectrometry (ICP-MS) and scanning electron microscopy (SEM) for the qualitative and quantitative analyses of metal particles in foods was devised and validated. Different raw materials and food products, like wheat, durum wheat, wheat flour, semolina, cookies, and pasta were considered. Attention was paid to the development of sample treatment protocols for each type of sample to avoid potential artifacts such as aggregation or agglomeration. The analytical protocols developed followed by ICP-MS and SEM investigations allowed us the quantitative determination and the morphological and dimensional characterization of metal nano- and microparticles isolated from the raw materials and finished food products considered. The ICP-MS method was validated in terms of linearity (0.8-80 μg/g and 0.09-9 μg/g for Fe and Ti, respectively), quantification limits (0.73 μg/g for Fe and 0.09 μg/g for Ti), repeatability (relative standard deviation (RSD) % equal to 10% for Fe and 20% in a wheat matrix as an example), and extraction recoveries (93 ± 2-101 ± 2%). Validation of the scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) measurements was performed working in a dimensional range from 1 to 100 μm with an estimated error in the size determination equal to 0.5 μm. ICP-MS data as well as SEM measurements showed a decrease in the concentration of metal particles from wheat to flour and from durum wheat to semolina samples, thus indicating an external contamination of grains by metal particles. These findings were confirmed by environmental SEM analysis, which allowed investigation of particles of lower dimensions. Generally, the largest number of particles was found in the case of iron and titanium, whereas particles of copper and zinc were only occasionally found without any possibility of quantifying their number.
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Solvothermal synthesis of ZnS[C2H4(NH2)2]0.5 nanosheets. CRYSTAL RESEARCH AND TECHNOLOGY 2011. [DOI: 10.1002/crat.201000690] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Pd/PdO functionalization of SnO2 nanowires and ZnO nanotetrapods. CRYSTAL RESEARCH AND TECHNOLOGY 2011. [DOI: 10.1002/crat.201000650] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Low temperature thermal evaporation growth of aligned ZnO nanorods on ZnO film: a growth mechanism promoted by Zn nanoclusters on polar surfaces. CrystEngComm 2011. [DOI: 10.1039/c0ce00670j] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Vapour-phase growth, purification and large-area deposition of ZnO tetrapod nanostructures. CRYSTAL RESEARCH AND TECHNOLOGY 2010. [DOI: 10.1002/crat.201000081] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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22
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Deposition of CdTe films under microgravity: Foton M3 mission. CRYSTAL RESEARCH AND TECHNOLOGY 2009. [DOI: 10.1002/crat.200900503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Preparation and characterization of powders and crystals of Vn-xTixO2n-1 Magneli oxides. CRYSTAL RESEARCH AND TECHNOLOGY 2005. [DOI: 10.1002/crat.200410488] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Morphological, structural and optical study of quasi-1D SnO2 nanowires and nanobelts. CRYSTAL RESEARCH AND TECHNOLOGY 2005. [DOI: 10.1002/crat.200410463] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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