Impact of annealing on R2R perovskite films

Student’s name: Aidan Wensel Home Institution: Lafayette College NNCI Site: RTNN @ UNC Chapel Hill REU Principal Investigator: Dr. Jinsong Huang – Department of Applied Physical Sciences, Department of Chemistry, UNC Chapel Hill REU Mentor: Dr. Luigi A. Castriotta and Allen Wood- Department of Chemistry, UNC Chapel Hill Abstract: Perovskites are a unique class of materials which can exhibit numerous physical phenomena which make them suitable for a wide variety of technological applications, including spintronics, photodetectors and solar cells. Perovskites can exhibit photovoltaic properties and thus are promising for reducing the cost and increasing the widespread use of commercial solar cells. While much of the basic science regarding perovskite use in solar cells is either established or is an area of ongoing research, the research into the scalability of these materials is catching up. One key benefit of this material is that it is conformal to any type of substrate, allowing it to be deposited on flexible materials. To ensure perovskites can be successfully scaled to the consumer level, the manufacturing processes surrounding the commercial fabrication of flexible perovskite solar cells (PSCs) must be designed. One such technique for thin film manufacturing is known as roll-to-roll, or R2R. R2R involves layering the thin-films of interest on a long flexible substrate that can be continuously moved and rolled, in a conveyor-belt style. While common in other thin-film technological manufacturing processes like in organic photovoltaics and thin-film batteries, R2R is still under development for use with perovskite materials. There are several challenges in adapting the R2R process to flexible PSC fabrication, including incorporating the necessary annealing step for crystallizing the precursor solution into perovskite film. The current annealing process involves inefficient time constraints for complete precursor conversion to perovskite. To address this, a new annealing process was designed, implemented, and tested, and the resulting perovskite films characterized. The perovskite films produced using this new annealing method were shown to be of suitable quality for photovoltaic devices.