Mark Chen In the past year, the Chen Lab has made significant advances in their development of open-shell organic materials, especially regarding their potential to serve as emitters. Led by the new synthesis developed by Imran, he and Caleb published a communication in the Journal of the American Chemical Society 2020, 142, 38) that describes a nitrogen-substituted bisphenalenyl π-radical cation that represents a structurally unique doublet emitter, and achieves conductivity via antiambipolar charge transport. Previously, antiambipolarity always required a heterojunction between two disparate material layers. A single layer device that employs our N-substituted π-radical cation is uniquely capable of achieving antiambipolar transport because of the similar energies of holes and electrons that result from a singly-occupied molecular orbital. Exploitation of this electronic property bears potential for simpler fabrication of devices capable of faster signal switching. The emissive properties of our bisphenalenyl compounds has also led to a collaborative effort between the Chen, Fredin, and Young Labs that is investigating how spin multiplicity affects fundamental electronic structure and photophysics. Since the N-substituted π-radical cation (RC) shares a near-identical emission with its oxidized dicationic (DC) form, we subjected the redox pair to a suite of experimental and computational analyses. We discovered that, despite their similar luminescent properties, DC and RC proceed by different emission mechanisms, where spin (un)pairing controls excited-state reorganization in RC. This manuscript was just recently accepted for publication in Chemical Science. Although the recent and ongoing pandemic did cause the cancellation of all in-person conferences/symposia and on-campus activities, at least temporarily, the group can report some positive social news from the past year. The group welcomed their newest graduate student, Gisselle Rojas, who graduated from Drew University where she worked with Lehigh Chemistry alumnus Prof. Kim Choquette. Kat Dunn also joined the group in Fall 2019 as an undergraduate researcher. In terms of graduations, the group had to sadly say good-bye to Marina Sutija and Olivea Vasquez who both graduated in May 2020 and moved-on to a chemical industry position in NJ and the start of a Chemistry Ph.D. at Tufts University, respectively. In the next few months, the group will be looking forward to Caleb’s Ph.D. graduation (who was a recipient of the College of Arts and Sciences Graduate Research Award in April 2020), along with submitting manuscripts regarding the development of an ink for colorimetric oxygen-sensing (Imran) and transparent organic thin films that achieve efficient electron conduction (Caleb). Greg Ferguson Despite the challenges in 2020, Zahed Ghelichkhah remained focused and busy, working in the lab to collect data using electrical impedance spectroscopy, and then and remotely to develop a quantitative description of the growth of an anodic oxide on gold using the point defect model (PDM). The PDM was developed by Digby MacDonald —currently Professor in Residence at UC Berkeley and Professor Emeritus at Penn State— who collaborated on the project. A full paper describing this work has been submitted and is currently under review. In addition, Kiran Khadka accepted a position as Senior Research Chemist at Versum Materials and plans to defend his PhD dissertation soon. In alumni news from the group, we recently heard from Kexin Chen (B.S., ’19), who completed a M.S. in Chemical Engineering Practice at MIT and is now applying to Ph.D. programs. Faculty News Page 8 · Lehigh University Oriana Fisher The Fisher Group welcomed its first members, graduate students Madhura Damle and Andrew Zimmerly, and settled into research space on the 6th floor of Mudd. They are looking forward to being able to safely return to the research projects they began before the pandemic on proteins involved in bacterial copper uptake and signal transduction. Dr. Fisher received a Lehigh Class of ’68 Faculty Fellowship and the lab was granted synchrotron beamtime at the Advanced Photon Source to pursue macromolecular crystallographic studies. Dr. Fisher published the following papers in the past academic year: Fisher, O.S.; Sendzik, M.R.; Ross, M.O.; Lawton, T.J.; Hoffman, B.M.; Rosenzweig, A.C. “PCuAC Domains from MethaneOxidizing Bacteria Use a Histidine Brace to Bind Copper” J Biol Chem. 2019, 294, 44, 16351-16363. Fisher, O.S.; Li, X.; Liu, W.; Zhang, R.; Boggon, T.J. “Crystallographic Studies of the Cerebral Cavernous Malformations Proteins” Methods Mol Biol. 2020, 2152, 291-302.
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