Please join Yale Chemistry for an Inorganic Chemistry Seminar with Prof. Hemamala Karunadasa, Associate Professor of Chemistry and Senior Fellow at the Precourt Institute for Energy, Stanford University.
Summary
The bandgaps of 3D lead-halide perovskites are dramatically varied by changing the halide. As the electronegativity of the halide decreases, so does the bandgap, leading to gaps that are suitable for absorbing sunlight in a solar cell. Unfortunately, the stability of halide perovskites also decreases as we move to the larger and less electronegative halides, like iodides. We recently found a way to circumvent this dichotomy by mixing organochalcogenides (RS-; R = organic group) with halides in perovskites. We can now access the higher stability of bromide or chloride perovskites, while the chalcogen (S, Se) orbitals form the highest energy-filled electronic bands, affording lower bandgaps than pure-bromide or -chloride perovskites. I will present our latest findings on how mixing halides and chalcogenides can tune the bandgap of the perovskites, in the ideal range for various photovoltaic applications. I will discuss the potential, as well as the remaining challenges, for extracting photocurrent from this new family of perovskites that may combine the properties of lead-halide and lead-chalcogenide solar absorbers. I will also present the surprising consequences of restricting the motion of the organic cation within the cubeoctahedral cavity of the perovskite framework.
For more information on Prof. Karunadasa’s research: Research - Stanford Chemistry.
Faculty Host: Amymarie Bartholomew
This seminar is generously sponsored by the Mrs. Hepsa Ely Silliman Memorial Fund.
Locations
Seminar, SCL 160
Lunch, SCL 218 (11:30-1:30 p.m.)
Coffee Talk, SCL 111 (3:00-4:00 p.m.)