March 2021 archive

Welcome to Liza, Kalika, Laura, and Aine!

A big welcome to our new rotation students, Liza and Kalika, as well as our two new undergrad researchers, Laura and Aine! Liza will work with Zach on using SSTA to understand organic materials, Kalika will work with James doing SSTA of perovskite nanocrystals, and Laura and Aine will be teaming up with Brandon to understand some squaraine molecules. Welcome to the lab!

James and Michael’s work presented at Willamette University

Thanks to Prof. David Griffith for the invitation to give a talk at Willamette University today. I presented James’ and Michael’s work on perovskite NCs and got a ton of excellent questions from the students at Willamette. I hope we soon see some of those students at UO as graduate students!

Thanks for a fantastic visit to Case Western Reserve University

Many thanks to Prof. Clemens Burda for hosting my seminar visit to Case today. It was great to chat with him and his awesome team of graduate students about their recent work, and meet some of the great faculty at Case. Thanks for the fun visit!

Zach’s new in situ measurements during polymer annealing presented at APS

Many thanks to Stephanie Lee and Takuji Adachi for the invitation to speak at this year’s APS meeting and for organizing a stimulating session on organic electronics. It was the first time we’ve presented Zach’s new SSTA measurements, collected in situ during polymer annealing! Great work, Zach!

Congrats to the newly minted Dr Morgan Sosa!

A huge congratulations to Dr Morgan Sosa on becoming a Dr this morning! Morgan did an excellent job in defending her dissertation, titled “Modeling the Evolving Mixture of H- and J-Aggregates During Organic Film Formation”. Morgan’s work in using the two-particle approximation to rapidly simulate and fit the absorption spectra of an organic molecule is a big step forward in our understanding of how a heterogeneous mixture of aggregates can form during the casting of a thin-film. Morgan drew a huge crowd of supporters and well-wishers. We will miss you both in our research group and more broadly in the UO community, Morgan! Congrats!

Congrats to Michael and James on the publication of their work in Nature!

A huge congratulations to Michael and James on their paper, “Ligand-engineered bandgap stability in mixed-halide perovskite LEDs”, which was published today in Nature. A mixture of halides can be used in perovskite NCs to tune their emission wavelength, but upon exposure to light or electrical bias these halides tend to segregate, changing their emission wavelength. Our collaborators at Oxford developed a method using short-chain, multi-dentate ligands to stabilize the surface of perovskite NCs, and we, along with collaborators in Korea, demonstrated that the use of these ligands inhibits halide-segregation. Michael performed incredibly difficult transient absorption measurements on the nanocrystals, trapping them in their segregated state to measure their excited state dynamics and demonstrate the inhibition of segregation upon exposure to light. James and Michael also used dilution studies to show that the mechanism of halide segregation is likely within single nanocrystals. James patiently and carefully wrote and revised large portions of this paper and I hope he and Michael enjoy seeing the culmination of their years of hard work in print at last! Many thanks to all of our collaborators, particularly Yasser Hassan and Henry Snaith for inviting us to be a part of this fruitful collaboration.