What is Shockley and Queisser Limit

Solar radiation is plentiful and a clean source of power. However, despite the first practical use of silicon based solar cell more than 50 years ago, it has not been exploited to its full potential due to the high cost of electrical conversion on a per Watt basis. Many new kinds of photovoltaic cells such as multi-junction solar cells dye –sensitized solar cells and organic solar cell incorporating element of nanotechnology have been proposed to increase the efficiency and reduce the cost. Nanotechnology, in the form of quantum dots, nanorods, nanotubes, and grapheme, has been shown to enhance absorption of sunlight, makes low cost flexible solar panels and increases the efficiency of photovoltaic cells. The chapter reviews the state of current photovoltaic cells and challenges it presents. It also discusses the use of nanotechnology in the application of photovoltaic cells and future research directions to improve the efficiency of solar cells and reduce the cost.