Constructing thermally activated delayed fluorescence dendrimers for solution processable blue OLEDs by molecular engineering of peripheral dendrons

Intramolecular Sensitization Assisting High-Efficiency TADF Conjugated Polymers with Accelerating Exciton Spin Flip for Solution-Processed Electroluminescent Devices

“…In addition, the dihedral angle of each part of the conjugated polymer skeleton is lower than 40°, which ensures that the delocalized main chain has good carrier transport performance. 35,36 The frontier molecular orbitals (FMOs) of the represented fragment of these conjugated polymers are shown in Figure 2c and 94.3% for S 0 → S 1 and S 0 → T 1 excitations, respectively, demonstrating that the photophysical properties of the emitter units can be effectively inherited into polymers.…”

“…The torsion angle between the TADF emitting unit and the conjugated backbone is as high as 89.8° due to the twisting effect of the spiral ring, which enables the design strategy of isolating the TADF emitting unit from the conjugated backbone. In addition, the dihedral angle of each part of the conjugated polymer skeleton is lower than 40°, which ensures that the delocalized main chain has good carrier transport performance. , …”

“…31−34 From previous works, it also can be concluded that the donor moieties of TADF molecules are greatly affected by the adjacent host units in the conjugated backbone once the TADF molecules are integrated into it. 35,36 The conjugation extension of the polymer backbone will increase the overlap of molecular orbitals during the electron transition, resulting in a larger energy gap between singlet and triplet states (ΔE ST ), which will inhibit RISC process and weaken the optoelectrical properties of polymeric emitters. 9,31,37 In this context, we also construct conjugated TADF polymers by embedding spirofluorene units into a conjugated backbone and connecting the TADF side chains to the backbone by sp3 carbon atoms.…”