Solution-processed infrared photovoltaic devices

Physically flexible, solution-processed solar cells have the potential to harvest light conveniently, cheaply and efficiently. Absorption of the considerable power in the infrared region of the solar spectrum is necessary for efficient solution-processed solar cells. We use lead sulphide (PbS) colloidal nanoparticles (quantum dots) that are quantum size effect tunable, allowing tailoring of absorption onset between 900 and 2000 nm. A number of device architectures were described within, leading to photovoltaic devices which exhibit external quantum efficiencies exceeding 1%.