Anna Paola Caricato

Dipartimento di Matematica e Fisica “E. De Giorgi”, Università del Salento, Lecce (Italia)

Gold nanoparticles deposited by laser ablation



Production and study of nanoparticles (NPs) have attracted considerable interest because of their unique properties that differ from those of the corresponding bulk materials. These properties originate from the intrinsic material characteristics, but on the top from their large surface to volume ratio or the fact that interaction with electromagnetic fields can induce coherent oscillations of the conduction electrons (Surface Plasmon Resonance - SPR).
Gold NPs are of great interest since they absorb light in the visible range and present excellent stability and biocompatibility. These properties make them attractive for application in several high technology fields such for example organic photovoltaics (OPV), catalysis, biology, medicine, sensors… The optical and electronic properties of gold NPs are tunable by changing their size, shape, surface chemistry, or aggregation state. For this reason, mucheffort has been focused on achieving precise control over NP morphology.
Among the different techniques for the deposition of NPs, laser based ones are very attractive because of their versatilities and the fact that stabilizersor templates, generally used to overcome thermodynamic instability during the NP-formation and determine their final size and shape, are not necessary.
After a brief description of the working principle of the laser ablation technique and of the most important deposition parameters, the main laser-assisted strategies for the deposition of gold NPs will be outlined.
Particular attention will be devoted to the deposition of gold NPs by ns laser ablation in vacuum for photovoltaic applications.  In particular, the effect of the inclusion of Au NPs produced by PLD in the active layer of an OPV cell in diffused bilayer geometry will be described. The optical and morphological properties of the Au NPs layer have been selected in order to evaluate the contribution of the surface plasmon resonance as enhancement factor of the solar cell efficiency, in a range size where light scattering is negligible.  

Date: 19/11/2014
Time:15:00 (coffee & cookies will be served at 14:45)
Place:FORTH Seminar Room 1