Luminescence Blinking of a Reacting Quantum Dot

Luminescence
blinking is an inherent feature of optical emission from individual
fluorescent molecules and quantum dots. There have been intense efforts,
although not with complete resolution, toward the understanding of
the mechanistic origin of blinking and also its mitigation in quantum
dots. As an advance in our microscopic view of blinking, we show that
the luminescence blinking of a quantum dot becomes unusually heavy
in the temporal vicinity of a reactive transformation. This stage
of heavy blinking is a result of defects/dopants formed within the
quantum dot on its path to conversion. The evolution of blinking behavior
along the reaction path allows us to measure the lifetime of the critical
dopant-related intermediate in the reaction. This work establishes
luminescence blinking as a single-nanocrystal level probe of catalytic,
photocatalytic, and electrochemical events occurring in the solid-state
or on semiconductor surfaces.