Halide Perovskites

Our work on these materials started with the synthesis and single particle photoluminescence study of nanoscale methylammonium lead halides. Our group was among the first to use heteronuclear solid state NMR spectroscopy to better understand the presence of not only crystalline but also amorphous and non-stoichiometric domains in lead halide perovskites. This allowed us to develop improved preparations of mixed halide perovskites with superior phase purity. At present, we are studying the recovery and replacement of lead and other critical elements in halide perovskite materials for photovoltaics (supported by Ames Lab LDRD).

https://patents.google.com/patent/US10872734B2/en

Heterobimetallic Complexes

We are fascinated by entities containing multiple metals and main group elements. Recently, we introduced different families of heterobimetallic molecular complexes as single source precursors in the synthesis of intermetallic materials. We also found that 10-14 complexes supported by heteropincer ligands are active catalysts in cross coupling reactions. Currently, we are developing heterobimetallic routes to nanoscale building blocks with specific electronic properties (supported by Lam Research).

https://pubs.acs.org/doi/10.1021/acs.inorgchem.2c00229

https://pubs.acs.org/doi/abs/10.1021/acs.organomet.9b00803

Multinary Semiconductors

For the past several years, we have worked on the synthesis of multinary pnictide and chalcogenide semiconductors containing alkali and other light elements. From a fundamental perspective, we are interested in advancing our ability to control and suppress phase segregation, a ubiquitous problem in solid state chemistry and materials science. From a practical perspective, we are interested in finding substitutes for technologically-relevant materials that contain toxic or critical elements (supported by National Science Foundation).

https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.0c01689

https://pubs.acs.org/doi/abs/10.1021/jacs.7b12873

Nano Catalysts

We are interested in better understanding the effects of nanostructuring on catalysis. We are also interested in applying nanocatalysts to challenging and new transformations. For example, we have studied the removal of nitrate from water using transition metal phosphides. More recently, we found that non-fcc intermetallics are uniquely selective in the reduction of nitroaromatics to azoxy- and azo-compounds (supported by Corbett Professorship).

https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.1c03557

https://pubs.acs.org/doi/abs/10.1021/acs.jpcc.1c08569

Quantum Dot Emitters

We have a long standing interest in studying the surface chemistry of nanocrystal quantum dots and related materials. We use heterocrystalline epitaxial shell growth as well as ligand modification in order to control surface defects and improve the optical properties of these materials. We rely on infrared and solid state NMR spectroscopies in order to unveil the exact mode of ligand binding as well as at- or near-surface inorganic structures at the atomic level (supported by collaborative grant from Department of Energy).

https://pubs.acs.org/doi/abs/10.1021/jacs.1c03162

https://pubs.acs.org/doi/abs/10.1021/jacs.9b05509