(366ab) Evaporation-Controlled Microstructure and Process Sensitivity in Perovskite Thin Films

My research focuses around developing a mechanistic understanding of process-structure and process-performance relationships in evaporating and crystallizing thin films. Other interests include mass transport modeling, nucleation and crystal growth, novel process scale up and manufacturing, solar energy, and the energy transition.

Related Oral Presentations:

Controlling Morphology Via Nucleation and Evaporation in Solution-Processed Perovskite Thin Films (ID: 690012)

Abstract:

In the last decade, organometallic halide perovskites have received much attention for enabling the next-generation of printable thin-film photovoltaics. Process-structure relationships in solution-processed perovskite films are known to depend largely on the solidification kinetics and solvent removal rates. The most uniform films are made via a nucleation-driven process which is characterized by a small aspect ratio i.e., an average grain size that is less than the wet film height at saturation. However, it is not immediately obvious how process variables, such as temperature and ink composition, will affect the resulting film quality and thus process development becomes a resource intensive and Edisonian endeavor. Here, we present confocal microscope studies to show how the microstructure of a perovskite film can transition from being nucleation-driven to crystal-growth-driven as a function of hold time under natural evaporation – demonstrating the need for well-defined process limits. A geometric argument based on the vertical and horizontal solute diffusion length scales is used to predict the approximate transition in film formation regimes as a function of the film height, evaporation rate, and solubility. This poster focuses on defining the quantitative process limits and process sensitivity based on factors that may explicitly be used to manipulate evaporation rates (e.g., temperature, pressure, solvent atmosphere). Ultimately, this work provides a starting point for formulating design rules that may aid in developing robust manufacturing and process control strategies for the continuous manufacturing of solution-processed perovskite photovoltaics.

Biosketch:

I am a fourth year PhD student in the Chemical and Biological Engineering Department at Drexel University under PIs Dr. Nicolas Alvarez and Dr. Richard Cairncross. I also work closely with Dr. Aaron Fafarman and Dr. Jason Baxter. I recently completed a six-month fellowship under Dr. Axel Palmstrom at NREL to study evaporation and process sensitivity in blade-coated perovskite devices. Prior to starting my PhD, I worked for over three years at Moderna – experience includes fundamental bench scale work on lipid nanoparticles, scale-up of lipid-based drug delivery platforms for multiple therapeutics and vaccines, and tech transfer to an external CMO.