  At cryogenic temperatures, the photoluminescence spectrum of monolayer
WSe2features a num-ber of lines related to the recombination of so-called
localized excitons. The intensity of these lines strongly decreases with
increasing temperature. In order to understand the mechanism behind this
phenomenon, we carried out a time-resolved experiment, which revealed a similar
trend in the photoluminescence decay time. Our results identify the opening of
additional nonradiative relaxation channels as a primary cause of the observed
temperature quenching of the localized excitons' photoluminescence.
