IMX Talks - Watching, Understanding, and Controlling the Formation of Functional Materials

Material synthesis is a very important aspect in human kinds endeavor to discover and create new materials for energy applications. In order to make materials with desired functions it is advantageous to know how these functions relate to structure, synthetic variables, arrangement of atoms and molecules and how functions evolve during synthesis.

The class of hybrid halide perovskite semiconductors has gained significant research attention due to its potential as highly efficient and cheap material for energy applications such as in photovoltaics, light emitting devices, and photodetectors. In this regard, the field of halide perovskites moves towards more and more complex compositions enabling improved device performance and stability. Most of the improvements however, are chemical intuition driven or achieved through empirical optimization of processing conditions. Establishing the relationships between synthesis condition and film properties will enable deliberate control of synthesis parameters and increase reproducibility. I will discuss the formation of halide perovskites from colloidal precursors including the initial stages of formation and the physicochemical evolution of properties via polydisperse nanocrystal nucleation and solvent-complexation. We identify for example how the Pb salt influences the crystallization pathway, how it can template morphology, and how additives can aid room temperature processing.

In this talk I will introduce a new multimodal in situ platform that we developed together with the Advanced Light Source (ALS) which allows for simultaneous optical as well as structural characterization of chemical solution synthesis. By correlating diffraction and photoluminescence (PL) measurements, I will show how in situ PL can reveal subtle changes throughout different synthetic steps of halide perovskites including nuclei formation, surface passivation, and the onset of film decomposition.
Bio: Carolin M. Sutter-Fella is a Staff Scientist in the Molecular Foundry at the Lawrence Berkeley National Laboratory (LBNL). Before joining the Foundry Carolin built her research program enabled by LBNL’s Glenn Seaborg Early Career Fellowship (2017). Her research focuses on synthesis of functional materials and understanding synthesis-property relationships using multimodal in situ techniques as well as development of novel in situ capabilities. She received her Ph.D. in Electrical Engineering from ETH Zürich, Switzerland, in 2014 where she worked on the synthesis of chalcogenide thin film solar cells. Before Carolin joined LBNL, she was a Swiss NSF postdoctoral fellow at UC Berkeley.