Photovoltaics are regarded by many as the most likely candidate for long term sustainable energy production, yet their implementation has been restricted by the high costs involved. Nevertheless, the theoretical limit on photovoltaic energy conversion efficiency, above 85%, suggests that there is room for substantial improvement of present commercially available solar cells, both silicon and thin-film based. Current research efforts are focused on implementing novel concepts to produce a new generation of low-cost, high-performance photovoltaics that make improved use of the solar spectrum. This book features contributions from pioneers of next generation photovoltaic research and presents a comprehensive account of the current state-of-the-art in all aspects of the field. Topics covered include multi-junction solar cells (the method closest to commercialisation), quantum dot solar cells, hot carrier solar cells, multiple quantum well solar cells and thermophotovoltaics. The final two chapters of the book consider the materials, fabrication methods and concentrator optics used for advanced photovoltaic cells. 'Next Generation Photovoltaics' will be an essential reference for graduate students and researchers working with solar cell technology.