Nanoscale Photovoltaics

Commercially available solar cells typically operate in the ray optics regime, where traversable distances within the solar cell are many wavelengths long. In this chapter, we cover nanoscale solar cells, where the dimensions are on the order of the wavelength. These solar cells interact with light in the wave physics regime, resulting in novel effects such as enhanced absorption cross-sections. We first discuss the absorption and scattering of light by nanoscale objects, where we distinguish between localized resonances and guided modes. We then discuss the photovoltaic properties such as the quantum efficiencies and open-circuit voltage in nanoscale objects, to conclude with a discussion of both single and arrays of nanowires, which comprise the most prevalent nanoscale solar cell.