title: Synthesis and sensing properties of D5hpentagonal silver star nanoparticles.
abstract: In this work, we use silver decahedral nanoparticle (AgDeNP) seeds to synthesize pentagonal silver stars (AgStDeNPs) and study the sensing properties of these nanoparticles. The regrowth process of AgStDeNPs is kinetically-controlled, so the purity of the seed NPs is critical to avoid secondary deposition in the highly non-equilibrium reduction. To control the regrowth process, surface blocking with sodium polyacrylate (PANa) was implemented. PANa moderates rough silver nanostructures typically obtained by reduction with ascorbic acid. To modulate polymer binding to the surface and thus to tune surface blocking, pH served as a key synthetic parameter. Under optimal regrowth conditions, new sliver was deposited on the highest energy sites of the decahedra - the vertices of the rims - to yield pentagonal stars. The universality of this regrowth process was established with several different seed particles. The sharpness and size of the stellated tips are tunable by the amount of added silver. Gold deposition onto AgStDeNPs enables the preparation of diverse structures with enhanced stability. Ease of transformation, e.g. rounding, of star branches opens a promising venue for enhanced SPR sensing. Also, AgStDeNPs enable femtomolar detection of 5,5-dithiobis(2-nitrobenzoic acid) in SERS.
authors.affiliation: Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Avenue W, Waterloo, Ontario, Canada N2L 3C5. vkitaev@wlu.ca.
authors.forename: Nicole
authors.initials: N
authors.lastname: Cathcart
authors.affiliation: Centre for Nanostructure Imaging, Department of Chemistry, University of Toronto, 80 St. George St. Rm. 50, Toronto M5S 3H6, Canada.
authors.forename: Neil
authors.initials: N
authors.lastname: Coombs
authors.affiliation: Centre for Nanostructure Imaging, Department of Chemistry, University of Toronto, 80 St. George St. Rm. 50, Toronto M5S 3H6, Canada.
authors.forename: Ilya
authors.initials: I
authors.lastname: Gourevich
authors.affiliation: Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Avenue W, Waterloo, Ontario, Canada N2L 3C5. vkitaev@wlu.ca.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kitaev