Brian Kang

Chemical and Biomolecular Engineering

Faculty Advisor: Prashant Kamat

Gradient Film with Cation Migration

Previous work on phase segregation in mixed halide perovskites was done over the 2020-21 Winter Session. FAPbI3 films were created, which took a lot of trial and error. This was used, with CsPbI3 films, to heat them together and observe cation migrations across the films (although with a lot of testing with iodine and bromine). However, with a lot of experimenting, there was too much blue-shifting. With a standard procedure for synthesis of the FAPbI3 films, these films will be used to chemically treat them in order to form a gradient cation film.
  
This research will continue with an altered procedure. The new films are rich in cesium on one side and rich in formamidiniuim on the other side. In this case, more focus will be given to the reaction between cesium and formamidiniuim, instead of how temperature plays as a factor between the reaction, which narrows the scope of the experiment. Creating a cesium solution and dipping the formamidiniuim slides will create a shift in the film, creating a gradient with a high concentration of cesium on one end, high concentration of formamidiniuim in one end, and the gradient in between. The Journal of the American Chemical Society provides a lot of insight in several articles about the absorbance over time and specific wavelengths.