Jenny Nelson is a physicist whose research is devoted to characterising the materials used to build and improve photovoltaic devices, which convert energy from the Sun into electricity. She applies a range of tools that include physical models, simulation and experiments to optimise the performance of such devices through their composite materials. Over the last twenty-five years, Jenny has worked with many types of energy converting materials, ranging from molecular materials to inorganic materials such as nanocrystalline oxides, and organic–inorganic hybrids. She uses information describing the electronic, optical and structural properties of these materials to inform the design of her devices, an approach that has garnered strong interest from industry. Since 2010, Jenny has also been studying the potential of photovoltaic technologies to reduce the amount of carbon dioxide that is emitted during the generation of electricity, lessening the impact on climate change. She is the author of a popular text book, The Physics of Solar Cells (2003).