Dibenzophenazine‐Based TADF Emitters as Dual Electrochromic and Electroluminescence Materials

Previous work has reported the synthesis of donor–acceptor–donor molecules based on dibenzophenazine acceptor group, presenting thermally activated delayed fluorescent (TADF) properties and their application in the assembly of highly efficient electroluminescent devices. Herein, we focus on the characterisation of charge carrier species through UV‐Vis‐NIR spectroelectrochemical and potentiostatic EPR techniques, in addition to the investigation of electropolymerisation properties of some compounds depicted in this study. The promising electrochromic features of both small molecules and conjugated polymers led to the assembly and investigation of electrochromic devices, evidencing the materials’ versatility, applied in such different approaches as electrochromic windows and electroluminescent devices. Furthermore, the assembled OLEDs provided high efficiencies, with small roll‐off, EQEs up to 20.5 % and luminance values up to 85 000 cd/m2. The change of donors in CT‐based molecules significantly influences the charge carrier generation and follow‐up reactions that affect the TADF emitter‘s stability. The TADF emitters can be easily electropolymerised, forming stable conjugated polymers. Electrochemically active TADF emitters possess significant electrochromic properties and can be used as both electrochromic and electroluminescence materials. The dual behaviour of the TADF emitters allows use in both OLED and Electrochromic Windows applications.