Identifying and Eliminating Emissive Sub-bandgap States in Thin Films of PbS Nanocrystals

TitleIdentifying and Eliminating Emissive Sub-bandgap States in Thin Films of PbS Nanocrystals
Publication TypeJournal Article
Year of Publication2015
AuthorsHwang, GWeon, Kim, D, Cordero, JM, Wilson, MWB, Chuang, C-HM, Grossman, JC, Bawendi, MG
JournalAdvanced Materials
Volume27
Issue30
Pagination4481 - 4486
Date Published2015/08/12/
Abstract

Chemical oxidation of under-charged Pb atoms reduces the density of trap states by a factor of 40 in films of colloidal PbS quantum dots for devices. These emissive sub-bandgap states are a byproduct of several standard ligand-exchange procedures. X-ray photoelectron spectroscopy measurements and density function theory simulations demonstrate that they are associated with under-charged Pb.