  In this work, we have simulated the processes of broadening the first exciton
band in optical absorption spectra (OA) for InP/ZnS ensembles of colloidal
quantum dots (QDs). A phenomenological model has been proposed that takes into
account the effects of the exciton-phonon interaction and allows one to analyze
the influence of the static and dynamic types of atomic disorder on the
temperature changes in the spectral characteristics in question. To vary the
degree of static disorder in the model system, we have used a parameter
${\delta}$, which characterizes the QD dispersion in size over the ensemble.
Also, we have calculated the temperature shifts of the maxima and changes in
the half-width for the exciton peaks in single nanocrystals (${\delta}$ = 0),
as well as for the integrated OA bands in the QD ensembles with different
values of ${\delta}$ = 0.6 - 17%. The simulation results and the OA spectra
data measured for InP/ZnS nanocrystals of 2.1 nm (${\delta}$ = 11.1%) and 2.3
nm (${\delta}$ = 17.3%) are in good mutual agreement in the temperature range
of 6.5 K - RT. It has been shown that the contribution of static disorder to
the observed inhomogeneous broadening of the OA bands for the QDs at room
temperature exceeds 90%. The computational experiments performed indicate that
the temperature shift of the maximum for the integrated OA band coincides with
that for the exciton peak in a single nanocrystal. In this case, a reliable
estimate of the parameters of the fundamental exciton-phonon interaction can be
made. Simultaneously, the values of the specified parameters, calculated from
the temperature broadening of the OA spectra, can be significantly different
from the true ones due to the effects of static atomic disorder in real QD
ensembles.
