High efficiency, broadband solar cell architectures based on arrays of volumetrically distributed narrowband photovoltaic fibers.

We propose a novel solar cell architecture consisting of multiple fiber-based photovoltaic (PV) cells. Each PV fiber element is designed to maximize the power conversion efficiency within a narrow band of the incident solar spectrum, while reflecting other spectral components through the use of optical microcavity effects and distributed Bragg reflector (DBR) coatings. Combining PV fibers with complementary absorption and reflection characteristics into volume-filling arrays enables spectrally tuned modules having an effective dispersion element intrinsic to the architecture, resulting in high external quantum efficiency over the incident spectrum. While this new reflective tandem architecture is not limited to one particular material system, here we apply the concept to organic PV (OPV) cells that use a metal-organic-metal-dielectric layer structure, and calculate the expected performance of such arrays. Using realistic material properties for organic absorbers, transport layers, metallic electrodes, and DBR coatings, 17% power conversion efficiency can be reached.