Exploring new Chemically Processed, Scalable and Stable Bi-based Inorganic Photovoltaics Films

The photovoltaics field has been revolutionized by the emergence of lead-based hybrid perovskites. These materials are high quality semiconductors that can be deposited cheaply, from solution, at room temperature. However, the toxicity of lead and stability issues for these perovskites are driving a new search for more benign and stable alternatives. In this project we will try to find other chemically processable Bi based compounds which resemble the same defect tolerance as Lead based perovskites, but tackling the two major drawbacks mentioned earlier. The project will study the effect of systematic doping of BiOI with chalcogenides S and Se on the optical and electronic properties of the films. The aim is to form idealized microstructures in large area, chemically grown thin films and in doing so optimize the physical properties and optimize transport properties to give long diffusion lengths. Different experiments will be conducted and will give insight into routes to improve the transport properties and minority-carrier lifetimes in BiOI and related films, and to maximize charge extraction at device interfaces, all of which should provide a route to more efficient photovoltaic devices.