Coupled optical and electrical modeling of solar cell based on conical pore silicon photonic crystals

We compare the efficiency of thin film photonic crystal solar cells consisting of conical pores and nanowires. Solving both Maxwell's equations and the semiconductor drift-diffusion in each geometry, we identify optimal junction and contact positions and study the influence of bulk and surface recombination losses on solar cell efficiency. We find that using only 1 mu m of silicon, sculpted in the form of an inverted slanted conical pore photonic crystal film, and using standard contact recombination velocities, solar power conversion efficiency of 17.5% is obtained when the carrier diffusion length exceeds 10 mu m. Reducing the contact recombination velocity to 100 cm s(-1) yields efficiency up to 22.5%. Further efficiency improvements are possible (with 1 mu m of silicon) in a tandem cell with amorphous silicon at the top. (C) 2013 AIP Publishing LLC.