Improvement of photovoltaic efficiency using 3D photonic-crystal enhanced light trapping and absorption

The potential of using three-dimensional photonic crystals (PCs) for achieving highly absorptive photovoltaic devices is presented in this study. The diffractive effects of PCs, used as an intermediate layer in the optical collector, on the optical absorption of the photovoltaic structure are theoretically investigated. Different PC configurations implemented in the photovoltaic collectors are modeled, and their absorption enhancements are compared. Longer matter-radiation interaction time for the photovoltaic devices with a PC-based collector results in higher absorption enhancement when compared to the devices using a slab of equivalent volume without a PC structure. The results show that employing simple-cubic (SC) PCs of inverted opal structure facilitates a much stronger enhancement of the absorption efficiency in photovoltaic devices than using the other kinds of PCs. By coupling a SC PC to the intermediate layer of the collector, the enhancement factor across the spectral range (480-1127 nm) could be created by about 2, relative to an ordinary layer of equivalent volume. (C) 2011 Elsevier B.V. All rights reserved.