Determining long-lived photo-excited species in thin-film anthracene derivatives using quasi-continuous wavelength photo-induced absorption

Long-lived excited states dynamics of sky-blue emitting 9,10-bis [9-hexyl-6-((E)-styryl)-9H-carbazol-3-yl] anthracene derivatives have been investigated by means of time-correlated single photon counting and quasi-continuous wavelength photo-induced absorption (QCW-PIA) spectroscopies. The QCW-PIA is a versatile tool to investigate the long-lived photo-excited species with lifetimes ranging from microsecond to millisecond time scale. In this time regime, mobile and trapped polarons were recognized, and their long and short mean lifetimes were estimated using a modulation frequency dependence technique at 20 K.