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Pyrlin SV, Hine NDM, Kleij AW, Ramos MMD. Self-assembly of bis-salphen compounds: from semiflexible chains to webs of nanorings. SOFT MATTER 2018; 14:1181-1194. [PMID: 29349462 DOI: 10.1039/c7sm02371e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The recently-observed self-assembly of certain salphen-based compounds into neuron-like networks of microrings interconnected with nano-thin strings may suggest a new highly-potent tool for nanoscale patterning. However, the mechanism behind such phenomena needs to be clarified before they can be applied in materials design. Here we show that, in contrast with what was initially presumed, the emergence of a "rings-and-rods" pattern is unlikely to be explained by merging, collapse and piercing of vesicles as in previously reported cases of nanorings self-assembly via non-bonding interactions. We propose an alternative explanation: the compounds under study form a 1D coordination polymer, the fibres of which are elastic enough to fold into toroidal globules upon solvent evaporation, while being able to link separate chains into extended networks. This becomes possible because the structure of the compound's scaffold is found to adopt a very different conformation from that inferred in the original work. Based on ab initio and molecular dynamics calculations we propose a step-by-step description of self-assembly process of a supramolecular structure which explains all the observed phenomena in a simple and clear way. The individual roles of the compound' s scaffold structure, coordination centres, functional groups and solvent effects are also explained, opening a route to control the morphology of self-assembled networks and to synthesize new compounds exhibiting similar behaviour.
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Affiliation(s)
- Sergey V Pyrlin
- Department of Physics and Center of Physics, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.
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Abdellatif MH, Salerno M, Abdelrasoul GN, Liakos I, Scarpellini A, Marras S, Diaspro A. Effect of Anderson localization on light emission from gold nanoparticle aggregates. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:2013-2022. [PMID: 28144549 PMCID: PMC5238672 DOI: 10.3762/bjnano.7.192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 12/07/2016] [Indexed: 06/06/2023]
Abstract
The localization of light known as Anderson localization is a common phenomenon characterizing aggregates of metallic nanostructures. The electromagnetic energy of visible light can be localized inside nanostructures below the diffraction limit by converting the optical modes into nonradiative surface plasmon resonances. The energy of the confined photons is correlated to the size and shape of the nanostructured system. In this work, we studied the photoluminescence dependence of aggregates of 14 nm diameter gold nanoparticles (AuNPs) synthesized by drop-casting a liquid suspension on two different substrates of glass and quartz. The AuNP aggregates were characterized by electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The dielectric constant of the surrounding medium plays a crucial role in determining the aggregate geometry, which affects the Anderson localization of light in the aggregates and hence causes a red-shift in the plasmonic resonance and in the photoluminescence emission. The geometry of the gold nanoparticle aggregates determine the strength of the Anderson localization, and hence, the light emission from the aggregates. The photoluminescence lifetime was found to be dependent on the AuNP aggregate geometry and the dielectric constant of the medium.
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Affiliation(s)
- Mohamed H Abdellatif
- Nanophysics Department, Istituto Italiano di Tecnologia, via Morego, 30, I-16163 Genova, Italy
| | - Marco Salerno
- Nanophysics Department, Istituto Italiano di Tecnologia, via Morego, 30, I-16163 Genova, Italy
| | - Gaser N Abdelrasoul
- Nanophysics Department, Istituto Italiano di Tecnologia, via Morego, 30, I-16163 Genova, Italy
| | - Ioannis Liakos
- Smart Materials Group, Istituto Italiano di Tecnologia, via Morego, 30, I-16163 Genova, Italy
| | - Alice Scarpellini
- Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego, 30, I-16163 Genova, Italy
| | - Sergio Marras
- Nanochemistry Department, Istituto Italiano di Tecnologia, via Morego, 30, I-16163 Genova, Italy
| | - Alberto Diaspro
- Nanophysics Department, Istituto Italiano di Tecnologia, via Morego, 30, I-16163 Genova, Italy
- Department of Physics, University of Genoa, via Dodecaneso, 33, I-16146 Genova, Italy
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Fractal analysis of inter-particle interaction forces in gold nanoparticle aggregates. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.03.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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