The excited state dynamics of various chromophores were investigated via multiple ultrafast spectroscopic techniques. These chromophores are reported to have emission dynamics governed by the thermally activated delayed fluorescent (TADF) process. Many of the chromophores under investigation have been reported to have quantum yield enhancements under oxygen-free conditions. Furthermore, devices fabricated with these chromophores have been reported to have enhanced external quantum efficiency. Each of these findings have been widely attributed to the TADF mechanism. Our measurements were carried out in both ambient and oxygen-free solution, free of guest-host interactions. The time correlated single photon counting (TCSPC) measurements revealed that some of the reported chromophores lack the long-lived emissive component in either solution, while the others displayed an enhancement of this component’s lifetime. The nanosecond transient absorption spectroscopy measurements (nsTAS) revealed that the chromophores with a long-lived emissive component also posses excited states of triplet character. Our measurements reveal that only a certain set of the investigated chromophores possess the photophysics of a TADF chromophore.

Using ultra-fast spectroscopy to investigate the photophysical properties of reported TADF chromophores

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.