(Invited) Green Solutions for Next Generation Photovoltaics: Using Wood, Glass, and Aluminum

Abstract

To address the terawatt energy challenge, a focus is usually placed on improving the cost-per-Watt of solar generated power. However, as the scale of photovoltaic energy production increases, so do concerns about material availability, environmental impact, and recyclability. Here I will present an overview of technologies that we have been developing to address these issues based on two concepts: (i) inexpensive renewable materials (e.g. wood pulp and glass) to make effective light trapping and scattering structures and (ii) the possibility of using hot carrier injection in aluminum nanostructures to convert sunlight to power. In the first part, I will discuss how cellulose fibers can be transformed into a transparent thin-film anti-reflection coating that can be applied to virtually any solar cell technology. I will give two examples of solar cells that have efficiency improvements >20% as a result of these coatings. In the second part, I will discuss loss mechanisms that are found in typical solar cells and will specifically address ways to capture energy that is usually lost as heat due to the cooling of excited carriers prior to collection. I will present trade-offs for these different schemes and future directions for high efficiency, green photovoltaics.