Thermodynamics and Optical Response of Palladium-Gold Nanoparticles

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dc.contributor.authorRahm, Magnus
dc.contributor.departmentChalmers tekniska högskola / Institutionen för fysik (Chalmers)sv
dc.contributor.departmentChalmers University of Technology / Department of Physics (Chalmers)en
dc.date.accessioned2019-07-03T14:24:57Z
dc.date.available2019-07-03T14:24:57Z
dc.date.issued2016
dc.description.abstractAlloyed nanoparticles of palladium (Pd) and gold (Au) are promising candidates for hydrogen sensing in e.g., cars powered by fuel cells. Specifically, the plasmonic response of Pd-Au nanoparticles changes upon absorption of hydrogen, enabling quantitative measurement of the hydrogen partial pressure. The optical properties of alloyed nanoparticles are not only dependent on the concentration of the respective element, but also on the atomic ordering. This thesis presents atomistic simulations as well as first-principles calculations on Pd-Au nanoparticles, where the former aim at elucidating the thermodynamics, and the latter were conducted to investigate the optical properties of representative particles. A novel algorithm for determination of optical nanoparticle shapes, based on Monte Carlo simulations, is also presented. The atomistic simulations show that Au tends to segregate to the surface of the nanoparticle, especially at corner and edge sites, while the subsurface layer exhibits a Pd excess. The first-principles calculations, specifically density functional theory (DFT) and time-dependent density functional theory (TDDFT), show that the electronic oscillations occur almost exclusively on the surface of the particles, while the interior atoms play an important role in screening of the optical response. The calculations do not, however, reveal any distinct plasmonic peak in the optical absorption spectra.
dc.identifier.urihttps://hdl.handle.net/20.500.12380/247408
dc.language.isoeng
dc.setspec.uppsokPhysicsChemistryMaths
dc.subjectNanovetenskap och nanoteknik
dc.subjectGrundläggande vetenskaper
dc.subjectHållbar utveckling
dc.subjectInnovation och entreprenörskap (nyttiggörande)
dc.subjectNanoteknik
dc.subjectNanoscience & Nanotechnology
dc.subjectBasic Sciences
dc.subjectSustainable Development
dc.subjectInnovation & Entrepreneurship
dc.subjectNano Technology
dc.titleThermodynamics and Optical Response of Palladium-Gold Nanoparticles
dc.type.degreeExamensarbete för masterexamensv
dc.type.degreeMaster Thesisen
dc.type.uppsokH
local.programmeApplied physics (MPAPP), MSc
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