3D photonic crystals for ultra-light trapping in solar cells

We suggest three-dimensional photonic crystals as a direction selective filter for ultra-light trapping in solar cells. 3D photonic crystals allow tailoring of the photonic stop gap in space and energy. We analysed different photonic crystal structures concerning their spectral and direction selective properties and defined two figures of merit for our application: a quality factor and a transmission coefficient. By analysing different experimentally feasille 3D photonic crystals, we found that the inverted opal has the best properties. We verified the direction selective properties of the inverted opal in the microwave spectral range and found a very good agreement between experiment and simulation.