PbS Nanocrystal Emission Is Governed by Multiple Emissive States

• DOI: 10.1021/acs.nanolett.6b02147
• Publication Date: 2016-09-14T17:23:10Z
• Authors: Justin R. Caram; Sophie N. Bertram; Hendrik Utzat; Whitney R. Hess; Jessica A. Carr; Thomas S. Bischof; Andrew P. Beyler; Mark W. B. Wilson; Moungi G. Bawendi
• Keywords: Laser linewidth; Lead sulfide; Mesoscopic physics; Stokes shift; Nanosecond

Lead chalcogenide colloidal nanocrystals (NCs) are promising materials for solution processable optoelectronics. However, there is little agreement on the identity and character of PbS NC emission different degrees quantum confinement—a critical parameter realizing applications these nanocrystals. In this work, we combine ensemble single spectroscopies to interrogate preparations lead sulfide NCs. We use photon correlation Fourier spectroscopy (S-PCFS) measure average linewidth near-infrared-emitting dots find it be dominated by homogeneous broadening. further characterize NCs using temperature-dependent linear time-resolved which demonstrate that a kinetically accessed defect state dominates room temperature highly confined emitting These experiments, taken together, Stokes shift result from two states: thermally defect—with an energetically pinned charge carrier—and inhomogeneously broadened band-edge state.