Amorphous Silicon Solar Cells With Silver Nanoparticles Embedded Inside the Absorber Layer
- PDF / 1,651,945 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 58 Downloads / 160 Views
1245-A07-20
Amorphous Silicon Solar Cells with Silver Nanoparticles Embedded Inside the Absorber Layer Rudi Santbergen, Renrong Liang and Miro Zeman Delft University of Technology, Photovoltaic Materials and Devices laboratory/DIMES, P.O. Box 5053, 2600 GB Delft, Netherlands, Tel: +31-15-2784425, Email: [email protected]
ABSTRACT A novel light trapping technique for solar cells is based on light scattering by metal nanoparticles through excitation of localized surface plasmons. We investigated the effect of metal nanoparticles embedded inside the absorber layer of amorphous silicon solar cells on the cell performance. The position of the particles inside the absorber layer was varied. Transmission electron microscopy images of the cell devices showed well defined silver nanoparticles, indicating that they survive the embedding procedure. The optical absorption of samples where the silver nanoparticles were embedded in thin amorphous silicon layer showed an enhancement peak around the plasmon resonance of 800 nm. The embedded particles significantly reduce the performance of the fabricated devices. We attribute this to the recombination of photogenerated charge carriers in the absorber layer induced by the presence of the silver nanoparticles. Finally we demonstrate that the fabricated solar cells exhibit tandem-like behavior where the silver nanoparticles separate the absorber layer into a top and bottom part.
INTRODUCTION Thin-film hydrogenated amorphous silicon (a-Si:H) solar cells have the potential to provide large-scale solar electricity at low cost [1]. To keep the inherent light-induced degradation and the production costs of the a-Si:H solar cell low, the thickness of its absorber layer has to be kept as thin as possible. Reducing the thickness of the absorber layer will reduce the absorption especially in the near infrared part of the solar spectrum. To compensate for this reduction, light-trapping techniques are implemented to significantly increase the path length of weakly absorbed light [2]. The standard techniques are based on light scattering at textured interfaces and reflection of light by the back reflector. A novel technique for light scattering in solar cells, not relying on surface roughness is light scattering through excitation of localized surface plasmons in metal nanoparticles. Metal nanoparticles scatter visible and near infrared light extremely efficiently and their optical properties are highly tunable by manipulating the particles’ size, shape and mutual distance. Recent progress in nanotechnology has made it possible to produce suitable metal nanoparticles. This has opened up the possibility to realize very efficient light trapping schemes in solar cells [3]. However, metal nanoparticles can also introduce optical losses by absorbing light or by scattering it away from the absorber layer. Therefore, there is still room to improve the design of a nanoparticle enhanced solar cell. Thus far, mainly solar cell designs with nanoparticles in front of or behind the absorber layer hav
Data Loading...
