dc.contributor.advisor	Xia, Younan
dc.contributor.author	Pawlik, Veronica Dana
dc.contributor.committeeMember	Wilkinson, Angus
dc.contributor.committeeMember	Sadighi, Joseph
dc.contributor.committeeMember	McDaniel, Jesse
dc.contributor.committeeMember	Chen, Hailong
dc.contributor.department	Chemistry and Biochemistry
dc.date.accessioned	2024-01-10T18:50:55Z
dc.date.available	2024-01-10T18:50:55Z
dc.date.created	2023-12
dc.date.issued	2023-12-08
dc.date.submitted	December 2023
dc.date.updated	2024-01-10T18:50:56Z
dc.description.abstract	Nanomaterials have long fascinated both the casual observer and scientific mind alike. The utility of Au nanocrystals in particular has inspired applications ranging from plasmonics to catalysis. Over time, the ability to finely tune both shape and size has greatly improved their merits for these applications. To further expand and enhance the properties of Au nanocrystals, bimetallic compositions were introduced. Of the various atomic arrangements possible for bimetallic nanocrystals, the core-shell structure is most commonly utilized. This morphology is typically synthesized through a seed-mediated process. Growing one metal on another can introduce challenges. In this dissertation, I explore the effects that increasing lattice mismatch has on the seed-mediated growth of noble-metal nanocrystals. First, the case of no lattice mismatch was investigated during the growth of Au on Au spherical seeds to generate AuRD fully enclosed by {110} facets. The lack of lattice mismatch led to layer-by-layer growth. The kinetics of the synthesis could easily be tuned to favor either deposition or diffusion to achieve concave RD, trisoctahedra, or octahedra. These AuRD were then utilized in another seed-mediated growth to improve the thermal stability of the AuRD. Specifically, 1 ML of Pt was added and this ultrathin layer of Pt was able to improve the thermal stability of the high energy {110} facets from degrading at 100 °C to persisting at 450 °C. Computational studies revealed that the thermal stability of the Au-supported Pt skin was even greater than that expected for pure Pt. This effect was attributed to the strain induced by the formation of a 3.8% lattice-mismatched Pt overlayer on Au. Finally, single-crystal Rh@Au truncated octahedra were synthesized at a lattice mismatch of 7.2%. The large mismatch led to an island growth mode, which, could be tuned through the use of gentle kinetic knobs. The addition of NaOH indirectly increased the reduction rate to help modulate the number of Au islands formed on the Rh seeds. Conversely, the addition of KBr slowed down the reduction, allowing the Au adatoms to diffuse across the Rh seed. This work provides insight into the effects of lattice mismatch on the growth mode of nanocrystals, moving one step closer to the rational synthesis of novel nanomaterials with desired characteristics.
dc.description.degree	Ph.D.
dc.format.mimetype	application/pdf
dc.identifier.uri	https://hdl.handle.net/1853/73182
dc.publisher	Georgia Institute of Technology
dc.subject	Seed-Mediated growth
dc.subject	nanocrystals
dc.subject	lattice mismatch
dc.subject	gold
dc.title	Seed-Mediate Synthesis of Gold Nanocrystals: The Effects of Lattice Mismatch on Growth Patterns
dc.type	Text
dc.type.genre	Dissertation
dspace.entity.type	Publication
local.contributor.advisor	Xia, Younan
local.contributor.corporatename	College of Sciences
local.contributor.corporatename	School of Chemistry and Biochemistry
relation.isAdvisorOfPublication	bfd1cb14-9d4d-4fd4-8876-cf0983c7c4ea
relation.isOrgUnitOfPublication	85042be6-2d68-4e07-b384-e1f908fae48a
relation.isOrgUnitOfPublication	f1725b93-3ab8-4c47-a4c3-3596c03d6f1e
thesis.degree.level	Doctoral

Title: Seed-Mediate Synthesis of Gold Nanocrystals: The Effects of Lattice Mismatch on Growth Patterns

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Seed-Mediate Synthesis of Gold Nanocrystals: The Effects of Lattice Mismatch on Growth Patterns