Thin film solar cells have the potential to significantly decrease the cost of photovoltaics. However, it is critical to trap light in the solar cell to increase light absorption, i.e. to increase the conversion efficiency. For this purpose, nano-sized structures, such as textured surface and nano–particle deposition on the surface, have been proposed.
In this example, we consider a n/p crystalline silicon thin-film solar cell with nano-sized metal (silver or gold) particles distributed on its surface, as shown above, and explain how to simulate the light absorption using FDTD. We assume that the particles are periodically located as shown below in the snapshot of FDTD’ layout editor (Fig.1). According to the simulation results, silver nano-particles can enhance absorption over the solar spectrum range by approximately 20%.
We consider simulations for normal and oblique incidence. The main difference between the two simulations is the type of plane wave source. For oblique incidence we use the Broadband Fixed Angle Source Technique (BFAST).