Improved solar cell efficiency through the use of an additive nanostructure-based optical downshifter [electronic resource] : final subcontract report January 28, 2010 - February 28, 2011 / Juanita Kurtin, SpectraWatt, Inc.
Golden, CO : National Renewable Energy Laboratory, 
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Title from title screen (NREL, viewed May 9, 2011).
This final report summarizes SpectraWatt's progress in achieving a boost in solar cell efficiency using an optical downshifter. Spectrawatt's downshifting technology is based on a nanostructured material system which absorbs high energy (short wavelength) light and reemits it at a lower energy (long wavelength) with high efficiency. This system has shown unprecedented performance parameters including near unity quantum yield and high thermal stability. The downshifter technology consists of a luminescent layer composed of chromophores embedded in a transparent matrix that is optically coupled to the solar cell. A fraction of the blue light incident on the luminescent material is absorbed by the chromophores (the fraction absorbed depends on chromophore loading) and re-emitted into the solar cell as red light. All other photons are absorbed by the solar cell directly. The chromophore that generates the optical properties is a Quantum Dot Heterostructure (QDH). Incorporation of the silica-encased QDH into PV encapsulants must be minimally disrupted to existing fabrication sequences of solar cell modules and, preferably, at no cost beyond that of the requisite materials.
Includes bibliographical references.
Prepared under Subcontract No. NEU-0-99010-10 DE-AC36-08GO28308 PV101199