"Defect-Tolerant? Nanoscale Insights into the Structural and Chemical Determinants of Halide Perovskite Optoelectronic Performance"

ABSTRACT:
Halide perovskites have attracted widespread interest for application in optoelectronics including solar cells, LEDs, and lasers because of their low-temperature synthesis and reported defect tolerance, in stark contrast to commercialized silicon and thin film technologies. In this talk, I will discuss how we are using nanoprobe X-ray microscopy to investigate the relationship between the defects that do appear in hybrid perovskites and optoelectronic performance and stability. Using a series of model materials, we have studied the heterogeneity in local chemistry and structure in these films and its significant impact on charge collection and degradation. I will also share insights from our in situ nanoprobe investigations of non-stoichiometry in operating perovskite solar cells. By understanding and mitigating defects in the bulk and at interfaces, we aim to systematically accelerate the development of these optoelectronic materials.

BIO:
Dr. David P. Fenning is an Assistant Professor in NanoEngineering at UC San Diego, where his group researches materials for solar energy conversion and storage. Currently, his work focuses on defects and reliability in silicon and hybrid perovskite solar cells and CO2 electrocatalysis for solar fuels. After completing his Ph.D. on silicon solar cell materials at MIT in 2013, he worked with the silicon R&D team at 1366 Technologies Inc., followed by an MIT/Battelle postdoctoral fellowship in solar fuels. He joined the NanoEngineering department at UC San Diego in 2015. He is a recipient of the American Chemical Society’s PRF New Investigator award and was recognized as a 2017 Hellman Fellow. His research is supported by the DOE SunShot Initiative and the California Energy Commission.