Broadband optical absorption enhancement through coherent light trapping in thin-film photovoltaic cells

Article (PDF Available)inOptics Express 16(8):5385-96 · May 2008with83 Reads
DOI: 10.1364/OE.16.005385 · Source: PubMed
We show that optical absorption in thin-film photovoltaic cells can be enhanced by inserting a tuned two-component aperiodic dielectric stack into the device structure. These coatings are a generalization and unification of the concepts of an anti-reflection coating used in solar cells and high-reflectivity distributed Bragg mirror used in resonant cavity-enhanced narrowband photodetectors. Optimized two-component coatings approach the physically realizable limit and optimally redistribute the spectral photon density-of-states to enhance the absorption of the active layer across its absorption spectrum. Specific designs for thin-film organic solar cells increase the photocurrent under AM1.5 illumination, averaged over all incident angles and polarizations, by up to 40%.