Dr. Nicholas Anderson & Dr. Lance Wheeler, National Renewable Energy Laboratory (NREL)
4:00pm - 5:00pm
Room 320 Havemeyer
Size-tunable optical properties and the ability to process thin films using scalable, cost-efficient printing techniques have long made colloidal nanocrystals (NCs) an attractive candidate for next-generation optoelectronics. Much of the recent progress in this direction hinges on the ability to manipulate the NC surface. The surface chemistry of a NC is directly related to the covalency of the semiconductor lattice. The more polar metal chalcogenide NCs have a mixture of empty (metal-like) and filled (chalcogenide-like) surface sites, bound by Lewis bases (L-type ligands) and Lewis acids (Z-type ligands) respectively. On the other hand, covalent semiconductors from Group IV have radical surface sites that covalently bond to X-type ligands. In both cases, electrically-insulating native ligands must be exchanged to produce conductive NC arrays for devices. By connecting the dots between metal chalcogenide and Group IV semiconductors and drawing analogies between metal-center complexes and NCs, we will discuss surface chemistry characterization and functionalization of these materials, with the goal of developing a universal model for understanding NCs surfaces.