New Direct Approach for Determining the Reverse Intersystem Crossing Rate in Organic Thermally Activated Delayed Fluorescent (TADF) Emitters.

We developed a new optical method to determine the rate of reverse intersystem crossing () in thermally activated delayed fluorescent (TADF) organic chromophores using time-resolved transient absorption spectroscopy. We successfully correlated the of the TADF-chromophores with device performance. Specifically, we focused on the external quantum efficiency (η) and the stability of the device at high brightness levels.