We
systematically studied temperature-dependent emission kinetics
in solid films of solution-processed CdSe nanoplatelets (NPLs) that
are either intentionally stacked or nonstacked. We observed that the
steady-state photoluminescence (PL) intensity of nonstacked NPLs considerably
increases with decreasing temperature, whereas there is only a slight
increase in stacked NPLs. Furthermore, PL decay time of the stacked
NPL ensemble is comparatively much shorter than that of the nonstacked
NPLs, and this result is consistent at all temperatures. To account
for these observations, we developed a probabilistic model that describes
excitonic processes in a stack using Markov chains, and we found excellent
agreement between the model and experimental results. These findings
develop the insight that the competition between the radiative channels
and energy transfer-assisted hole trapping leads to weakly temperature-dependent
PL intensity in the case of the stacked NPL ensembles as compared
to the nonstacked NPLs lacking strong energy transfer. This study
shows that it is essential to account for the effect of NPL stacking
to understand their resulting PL emission properties
