Vladimir Bulović, Professor, EECS (Thesis supervisor)
Rajeev Ram, Professor, EECS
Moungi Bawendi, Professor, Chemistry
In recent years lead halide based thin-film perovskites have emerged as a promising direct bandgap semiconductor for light absorption and emission applications. This is in part due to their compositional tunability and potential alloying that allows their color to be tuned from the near-IR through the visible spectrum. Additionally, these materials are moderately soluble, opening the door to solution processing methods rather than traditional physical or chemical vapor-based growth. For photovoltaic applications, the thin-film devices created using perovskite materials are thin relative to silicon wafer-based counterparts and therefore have the potential to be used in mechanically flexible cell architectures. This allows for high-speed roll-to-roll printing and coating processes as pathways for large scale manufacturing.
Here, the challenges of scaling these materials are discussed from multiple vantage points keeping end slot-die manufacturing in mind. First, as these are ink-based materials, governmental regulations on the use of solvents is considered and a technoeconomic model is created to guide manufacturing scale-up development. Second, the solubility limits of these materials are determined and novel ligand based multi-component inks are developed that fit within the economic limits of regulation. Lastly, a novel ink-based recrystallization method is presented that is capable of accessing all industrially relevant stable perovskite compositions with minimal post-annealing requirements. We use these inks and recrystallization methods on both lab scale and larger area slot-die coating techniques for high-efficiency photovoltaic devices.