title: Stabilization and Encapsulation of Gold Nanostars Mediated by Dithiols.
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.
authors.affiliation: Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009, Donostia - San Sebastián, Spain.|Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 3 Research Link, Singapore, 117602, Singapore.
authors.forename: Yusong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009, Donostia - San Sebastián, Spain.
authors.forename: Ana Belén
authors.initials: AB
authors.lastname: Serrano
authors.affiliation: EMAT-University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp, Belgium.
authors.forename: Kadir
authors.initials: K
authors.lastname: Sentosun
authors.affiliation: EMAT-University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp, Belgium.
authors.forename: Sara
authors.initials: S
authors.lastname: Bals
authors.affiliation: Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009, Donostia - San Sebastián, Spain.|Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Liz-Marzán
keywords: gold nanoparticles; gold nanostars; hot spots; surface capping; surface-enhanced Raman scattering