Simulation of Plasmonic Effects in Silicon-Based Thin-Film Solar Cells
Increasing performance and reducing production costs are the main objectives of current research in the field of silicon thin-film solar cells. High efficiencies are only achieved in a-Si:H and μc-Si:H silicon thin-film solar cells by means of “light-trapping” concepts, which lengthen the effective optical path of photons in the absorber layer. Randomly structured, highly scattering front contacts and reflecting back contacts are currently being used to this end.
New structures or optical elements with an improved light-trapping concept are therefore of particularly great interest. One promising option, which is, however, as yet almost uninvestigated, is the special optical properties of metallic nanoparticles and nanostructured metallic surfaces, so-called plasmons.
On the left side, you can see the schematic of a dipolar plasmonic resonance in a spherical metallic nanoparticle. The coherent oscillation of the electron gas produces space-charge zones. On the right side, you can see the corresponding electric fields.
The simulations (data points) can, in idealized cases, be compared with the semi-analytical Mie theory (solid line). The figure on the left side shows the absorption of a spherical nanoparticle for various surrounding materials.