Jeffrey DuBose

Chemistry and Biochemistry

Faculty Advisor: Prashant Kamat

Revealing the Role of Ionic Liquids in Stabilizing Perovskite Solar Cells

Perovskites are the most promising material for next-generation solar panels due to their low cost, high efficiency, and simple incorporation into existing technologies[1]. The current state-of-the-art perovskites contain mixtures of several cations and anions in the perovskite crystal structure. Unfortunately, during normal operating conditions the cations and anions within perovskite solar panels migrate and form distinct regions – a process called phase segregation. This phase segregation process leads to poor performance and fast degradation of the material. Recently it has been shown that addition of ionic liquids – organic molecules that carry positive and negative charges – are able to stabilize perovskite solar cells even under harsh operating conditions[2]. Although these results are quite promising, it is unclear the exact role that the ionic liquid (IL) treatment plays in stabilizing the perovskite and how it impacts phase segregation. In this project, I will elucidate the role of the IL treatment by studying both cation and anion migration in perovskites films. Building upon my previous projects on phase segregation[3,4], both light- and field-induced segregation will be employed to gain a better understanding of how the presence of ionic liquid molecules lends stability to perovskites. Suppressing phase segregation is crucial, as segregation drastically lowers the performance of a solar cell[5]. Understanding the mechanism of how ILs impart stability will allow for better design of molecular additives for perovskite films.

References:  [1]: Zhang et al., Nature Energy, 2016   [2]: Lin et al., Science, 2020   [3]: DuBose et al., J. Am. Chem. Soc. 2020,   [4]: DuBose et al., Angew. Chemie, (Submitted; 2020)   [5]: Samu et al. ACS Energy Lett., 2017