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Title: Modelling hot carrier properties in plasmonic nanostructures
Author: Dal Forno, Stefano
ISNI:       0000 0004 7963 7580
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2019
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Plasmon-induced hot carriers processes in metallic nanostructured materials are becoming an important field of research due to their potential technological applications. For example, hot carriers have been found to have favorable properties for photocatalysis, photodetection and solar energy harvesting. Although there have been significant experimental efforts to understand hot carrier properties in nanoplasmonic systems, there exists a lack of theoretical models to underpin experimental findings and guide experimental progress towards promising systems. In this work we carry out theoretical calculations of hot carrier phenomena in mono-metallic and bi-metallic nanoparticles and also in thin metallic films. In particular, we propose a simple theoretical model to describe hot-carrier generation in mono- and bi-metallic nanoparticles (NPs). For this, we combine a classical description of the plasmons in nanostructures with quantum-mechanical calculations of the electronic structure. The decay of the plasmon into hot carriers is described using Fermi's golden and the optical and electronic properties of the NPs are derived within the quasistatic approximation and solving the Schroedinger equation for a spherical well, respectively. For the mono-metallic nanoparticles, we present results for a set of 6 plasmonic metals (Na, K, Al, Cu, Ag, Au). For the bi-metallic core-shell nanoparticles, we screen 100 different material combinations and predict their efficiency for photocatalytic applications. For the plasmonic thin films, we combine ab initio density-functional theory with the two-temperature model to describe the ultrafast thermalisation dynamics of hot electrons in titanium nitride. We investigate the lifetime of hot carriers due to the scattering with phonons and also include the effect of defects.
Supervisor: Lischner, Johannes Sponsor: Engineering and Physical Sciences Research Council ; Thomas Young Centre
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral