Nanoplasmonics for solar cells
Doktorsavhandling, 2014

The main source of our energy system, the fossil fuels, will eventually be depleted and also pose environmental and climate hazards. There is thus a need for alternative, renewable energy sources. Solar (photovoltaic) cells will play an important role as one of them. The photovoltaics research is extensive today, but the relatively high cost of solar cells and/or insufficient efficiency make them still often loose in the energy market competition. This thesis explores novel concepts for solar cell research, enabled by advances in nanotechnology, specifically applying the phenomenon called plasmon resonance in metal nanoparticles, to study and improve thin-film solar cells. The plasmon resonance is a collective oscillation of conduction electrons in a metal nanostructure, which can be excited by light. It leads to interesting and potentially useful interactions between nanoparticles and light; in particular, the electric field in the vicinity of the nanoparticle is enhanced compared to that of the incident light. This work focuses on employing the enhanced field to (i) improve light absorption in thin amorphous silicon (a-Si:H) films and (ii) to sense adsorption and diffusion of dye molecules in TiO2 films, used for dye-sensitized solar cells. In the first part of the thesis, optical and photoconductivity measurements were performed on ultrathin a-Si:H films, with and without Ag plasmonic nanoparticles, in order to quantify the light absorption in a-Si:H films caused by the enhanced near-field around the nanoparticles. The effect was studied for (i) systems of Ag nanodiscs coated with a-Si:H films of various thicknesses, and (ii) Ag cone/a-Si:H nanocomposites placed on a reflector-spacer structure with varied geometric parameters. Finite-element method calculations were used to connect observed experimental features to specific plasmon resonance modes, and to explain mechanisms of absorption enhancement in the a-Si:H films. The second part of the thesis is focused on adsorption and diffusion kinetics of dye molecules on TiO2 films, studied by Indirect NanoPlasmonic Sensing (INPS) and Quartz crystal microbalance with dissipation monitoring (QCM-D) techniques. Measurements on flat film model systems revealed details of adsorption and desorption kinetics and allowed extracting the corresponding rate constants. Incorporating plasmonic sensing nanoparticles within mesoporous TiO2 films provides a unique opportunity to resolve adsorption kinetics locally in the film (in this case, at the bottom of the mesoporous TiO2 films). Diffusion times for dye molecules through the mesoporous films were measured and modelled with a diffusion-front model. This allowed deriving the effective diffusion coefficient of the dye molecules in this system.

enhanced near-field

adsorption

titanium dioxide

Localized Surface Plasmon Resonance

amorphous hydrogenated Silicon

diffusion

Langmuir kinetics

Dye-Sensitized Solar Cell

plasmonic nanoparticle

mesoporous material

diffusion-front model

Kollektorn, Kemivägen 9, Chalmers university, Göteborg
Opponent: Prof. Albert Polman, FOM Institute AMOLF, Amsterdam

Författare

Viktoria Gusak

Chalmers, Teknisk fysik, Kemisk fysik

Diffusion and adsorption of dye molecules in mesoporous TiO2 photoelectrodes studied by indirect nanoplasmonic sensing

Energy and Environmental Sciences,; Vol. 6(2013)p. 3627-3636

Artikel i vetenskaplig tidskrift

In situ investigation of dye adsorption on TiO2 films using a quartz crystal microbalance with a dissipation technique

Physical Chemistry Chemical Physics,; Vol. 14(2012)p. 9037-9040

Artikel i vetenskaplig tidskrift

Thickness Dependence of Plasmonic Charge Carrier Generation in Ultrathin a-Si:H Layers for Solar Cells

ACS Nano,; Vol. 5(2011)p. 6218-6225

Artikel i vetenskaplig tidskrift

High aspect ratio plasmonic nanocones for enhanced light absorption in ultrathin amorphous silicon films

Journal of Physical Chemistry C,; Vol. 118(2014)p. 22840-22846

Artikel i vetenskaplig tidskrift

Real time adsorption and desorption kinetics of dye Z907 on a flat mimic of dye-sensitized solar cell TiO2 photoelectrodes

Journal of Physical Chemistry C,; Vol. 118(2014)p. 17116-17122

Artikel i vetenskaplig tidskrift

Styrkeområden

Nanovetenskap och nanoteknik

Energi

Materialvetenskap

Ämneskategorier

Atom- och molekylfysik och optik

ISBN

978-91-7385-962-2

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 3643

Kollektorn, Kemivägen 9, Chalmers university, Göteborg

Opponent: Prof. Albert Polman, FOM Institute AMOLF, Amsterdam

Mer information

Skapat

2017-10-07