A New Entry to Purely Organic Thermally Activated Delayed Fluorescence Emitters Based on Pyrido[2,3‐b]pyrazine‐Dihydrophenazasilines Donor‐Acceptor Dyad

A new family of thermally activated delayed fluorescence (TADF) emitters based on a twisted donor‐acceptor (D−A) dyad scaffold comprising of dihydrophenazasiline (D) and pyrido[2,3‐b]pyrazine (A) has been developed, and their properties have been investigated. Time‐resolved spectroscopic analysis in matrices revealed the detailed photophysical properties of the D−A compounds. These D−A compounds serve as the emitter for organic light‐emitting diodes (OLEDs), showing a moderate external quantum efficiency (EQE) up to 9% in CBP matrix. Furthermore, theoretical calculations uncovered the excited states nature of the developed TADF emitters.