Molecular materials for solar energy conversion and energy storage

Molecular electronic materials such as conjugated polymers and small molecules have attracted intense interest for applications in solar energy conversion as well as to light emission, thin-film electronics and other fields.... [ view full abstract ]

Molecular electronic materials such as conjugated polymers and small molecules have attracted intense interest for applications in solar energy conversion as well as to light emission, thin-film electronics and other fields. Their appeal lies in the potential to tune material properties (electronic, optical, mechanical and thermal) through control of chemical structure and molecular packing, whilst using facile fabrication methods. Achieving this goal has been challenging, however, due to the intrinsic disorder and structural heterogeneity of the materials and the lack of appropriate device-physics models to relate structure to physical properties. Recent developments in materials design, computational modelling and experimental characterisation have led to the demonstration of improved molecular materials systems for photovoltaic energy conversion. We will discuss the factors that control photovoltaic efficiency in molecular materials, considering the impact of chemical and physical structure on properties such as phase behaviour, electronic transport, light harvesting, and charge recombination and consider the limits to conversion efficiency in such systems. We then consider the application of conjugated polymers to electrochemical energy storage. We show how carefully designed conjugated polymers equipped with polar side chains can function as electrodes with fast charging capability in aqueous environments, and can be used to construct a stable battery device.