SBIR Phase I: Low-cost highly-reflective and light scattering dielectric nanoparticle based thin films for solar cells
National Science Foundation
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Small Business Information
815 Medary Avenue, Suite 201, Brookings, SD, 57006-1303
Socially and Economically Disadvantaged:
AbstractThis Small Business Innovation Research Phase I project aims to demonstrate the feasibility of an innovative concept in using highly reflective and light scattering nanoparticle thin films as solar cell back reflectors with the goal to replace high-vacuum processing techniques. Conventional back reflectors consist of a sputtered metal film, which requires high capital cost for large scale systems and frequent downtime due to maintenance, cleaning, and replacing of the sputtering targets. In addition, sputtered metal back reflectors can have adverse effects on the solar cell device. Solar cells with silver back reflectors can achieve record efficiencies, but silver migrates into the absorber material and deteriorates the performance and reliability. Further, silver does not adhere well to substrates used in solar cell manufacturing and readily oxidizes reducing its reflectivity. Instead, sputtered aluminum back reflectors are typically used in thin film solar industry, but aluminum absorbs light in a crucial portion of the sunlight spectrum resulting in moderate performance gains. This project will use the lower-cost electrophoretic deposition method to grow dielectric nanoparticle thin films. The anticipated result is a manufacturable nanoparticle back reflector that is equally as reflective as silver for high efficiency and reliable solar cells. The broader impact/commercial potential of this project is to produce high efficiency thin film solar cells using nanoparticle-based back reflectors. The proposed nanoparticle-based back reflector can be fabricated using the atmospheric electrophoretic deposition method and replaces the conventional approach of using high vacuum sputtering of metals, which can be expensive, time consuming, energy intensive, and have poor material utilization. Engineered nanoparticle-based films are an ideal way to obtain very high light scattering and reflective surfaces, which are required properties of back reflectors in high efficiency solar cells. A combination of high solar cell performance and low-cost manufacturing methods means that the proposed nanoparticle-based back reflector will be well positioned to succeed in a highly competitive solar market, which had sales of $82 billion in 2010. Beyond solar, additional applications for highly engineered nanoparticle-based films include backlight reflectors for high efficiency flat panel displays, superhydrophobic surfaces for self-cleaning and water shedding applications, textured/porous structures for electronic devices, and photonic structures for electro-optical devices. This project will promote technology-based economic development in the upper Midwest. Collaboration with South Dakota State University will train graduate and undergraduate students in nanomaterial science and engineering to advance the capabilities of the future workforce.
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