Plasmonic nanoparticles are a promising technology for increasing the absorption in thin ﬁlm solar cells. This thesis uses optical simulations to understand and optimise the role that plasmonics can play in thin ﬁlm solar cells.
The basics of plasmonics may be covered using the analytical Mie theory which describes a plane wave interacting with a spherical object. This can be extended to include core-shell spherical objects. A key finding is that if the shell refractive index is higher than the surrounding medium refractive index, the plasmonic scattering and near ﬁeld will be enhanced compared to shells with a lower refractive index. In order to investigate more complex geometries the ﬁnite element method is introduced.
In particular the method is used to simulate arrays of particles on a substrate to build the link between simulation and experiment. Simulations of large area arrays are very computationally expensive, therefore statistical averaging of single particle responses is performed. Using this method the experimental response of a particle array was able to be reproduced in simulations.
Ultra-thin ﬁlm solar cells are then introduced and some of the issues surrounding these devices are investigated via the scattering matrix method. It is shown that moving away from a metallic back contact to a transparent contact with a separated metallic back reﬂector increases the absorption in the absorbing layer.
Having studied both plasmonics and ultra-thin ﬁlm solar cells in isolation, they are then combined ﬁrstly using the ﬁnite element method. The effect of particle placement within the device structure is investigated. The result is that the best performance enhancement comes from particles integrated directly inside the absorbing layer.
Finally the previous methods of Mie theory for particle simulations and scattering matrix for layered stack simulations are combined to create a coupled method capable of rapid simulation of devices with integrated plasmonic nanoparticles. This model is then used to assess many diﬀerent device structures with the optimum being found for Ag core /
AlSb shell nanoparticles integrated into the absorbing layer of a device with a transparent back contact and an incoherent Ag back reﬂector. This ultra-thin device is able to reach 93% of the current of a conventional thin ﬁlm while only using 20% of the absorber
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