title: Emission Quenching in PbSe Quantum Dot Arrays by Short-Term Air Exposure.
abstract: Clear evidence for two emitting states in PbSe nanocrystals (NCs) has been observed. The flow of population between these two states as temperature increases is interrupted by the presence of nonradiative trap states correlated with the exposure of the NC film to air. Quenching of the higher-energy emission begins after only seconds of exposure, with the effect saturating after several days. Unlike short-term oxygen-related effects in solution, the emission quenching appears to be irreversible, signaling a distinction between surface reactivity in NCs in films and that in solution. The origin of the two emissive centers and the impact of trapping on other NC film properties (e.g., electron/hole mobilities) remain important issues to be resolved.
authors: †National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States.
authors: Helen E
authors: HE
authors: Chappell
authors: †National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States.
authors: Barbara K
authors: BK
authors: Hughes
authors: †National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States.
authors: Matthew C
authors: MC
authors: Beard
authors: †National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States.
authors: Arthur J
authors: AJ
authors: Nozik
authors: †National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States.
authors: Justin C
authors: JC
authors: Johnson
keywords: infrared; nanocrystals; oxidation; photoluminescence; spectroscopy; temperature