Abstract
High flux optical applications require materials with high brightness and
color pure emission. Colloidal nanocrystals are solution-processible with
tunable, spectrally narrow emission, and high brightness per emitter.
Multiexciton emission in colloidal nanocrystals can significantly
contribute to the brightness of the emission in high flux optical devices.
However, multiexciton emission also has the potential to contribute to
emission broadening, which reduces color purity. There is a need to
understand and control multiexciton behavior in colloidal nanocrystal.
Here we develop a third-order photon correlation technique to characterize
the average single nanocrystal triexciton quantum yield and lifetime in a
solution-phase experiment. This technique derives from the relationship
between the Poissonian probability of nanocrystal photon absorption and
the intrinsic probability of nanocrystal photon emission. We validate the
theoretical background of this technique by creating a numerical model to
simulate the diffusion and emission of many nanocrystals in solution. We
show that the average triexciton quantum yield and triexciton lifetime can
be extracted in a solution of nanocrystals. This work demonstrates a
method to investigate the triexciton optical properties of colloidal
nanocrystals. This technique will provide a better understanding of
multiexciton emission effects from colloidal nanocrystals integrated into
high flux optical devices.