It’s a Trap! Unravelling Reversible Charge Trapping in Nanocrystals Through Single Particle and Ensemble Studies

Thesis (Ph.D.)--University of Washington, 2016-08Copper containing semiconductors such as copper-doped ZnS and CuInS2 are classic phosphors materials that have had wide general use for decades. The photophysical processes of these bulk materials have been well studied. Recent application of these materials on the nanoscale has led to unique properties that are not exhibited in the bulk regime. Several properties, such as the large Stokes shift, tunable emission energy, and broad emission bandwidths have increased the general interest in copper containing nanomaterials. This thesis will reveal several remarkable photophysical aspects of these phosphors through studies of the ensemble, single particle, and time resolved luminescence to better understand new aspects of these materials that emerge on the nanoscale. Most notably, the homogeneous bandwidths, fluorescence blinking, and delayed luminescence were measured. The mechanistic implications of these properties and broader impact on the understanding of nanocrystal photophysics will be explained