Photovoltaic research has moved from popular solar cells, based on crystalline silicon substrates with thicknesses of around 250 μm, to the thin film structures saving large amount of the active material. The next generation of solar cells requires substantial increase of the energy conversion efficiency, which can be achieved by enhancing of the optical trapping inside the cell. In this work we study the efficiency of light trapping inside vertical silicon nanowire solar cells. The main focus is on the optical trapping inside single vertical nanowires, which can enhance optical absorption far beyond capabilities of a thin film. Spectral optical absorption modeling based on RCWA together with the electromagnetic field distribution analysis gave insight into the light trapping inside the nanowires. Results provide a guide for the optimization of nanowires diameters, density and length for maximal short circuit currents with minimal material demands.

Date Published: 20 September 2011
PDF: 9 pages
Proc. SPIE 8111, Next Generation (Nano) Photonic and Cell Technologies for Solar Energy Conversion II, 811110 (20 September 2011); doi: 10.1117/12.892690

Published in SPIE Proceedings Vol. 8111:
Next Generation (Nano) Photonic and Cell Technologies for Solar Energy Conversion II
Loucas Tsakalakos, Editor(s)