Stabilization and Encapsulation of Gold Nanostars Mediated by Dithiols |
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| Authors: | Yusong Wang Ana Belén Serrano Kadir Sentosun Sara Bals Luis M Liz‐Marzán |
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| Affiliation: | 1. Bionanoplasmonics Laboratory, CIC biomaGUNE, Donostia – San Sebastián, Spain;2. Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore;3. EMAT‐University of Antwerp, Antwerp, Belgium;4. Ikerbasque, Basque Foundation for Science, Bilbao, Spain |
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| Abstract: | Surface chemistry plays a pivotal role in regulating the morphology of nanoparticles, maintaining colloidal stability, and mediating the interaction with target analytes toward practical applications such as surface‐enhanced Raman scattering (SERS)‐based sensing and imaging. The use of a binary ligand mixture composed of 1,4‐benzenedithiol (BDT) and hexadecyltrimethylammonium chloride (CTAC) to provide gold nanostars with long‐term stability is reported. This is despite BDT being a bifunctional ligand, which usually leads to bridging and loss of colloidal stability. It is found however that neither BDT nor CTAC alone are able to provide sufficient colloidal and chemical stability. BDT‐coated Au nanostars are additionally used as seeds to direct the encapsulation with a gold outer shell, leading to the formation of unusual nanostructures including semishell‐coated gold nanostars, which are characterized by high‐resolution electron microscopy and electron tomography. Finally, BDT is exploited as a probe to reveal the enhanced local electric fields in the different nanostructures, showing that the semishell configuration provides significantly high SERS signals as compared to other core–shell configurations obtained during seeded growth, including full shells. |
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| Keywords: | gold nanostars gold nanoparticles hot spots surface capping surface‐enhanced Raman scattering |
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