Near ultraviolet thermally activated delayed fluorescence dimer and polymer for high performance solution-processed OLEDs

Developing organic fluorophore with near ultraviolet emission is both significant and challenging in organic light-emitting diodes (OLEDs). Here, flexible linking strategy was proposed to construct near UV dimer and polymer with classical TADF properties. The linking media hexane alkyl not only integrates functional monomer but also limited π-conjugation and molecular interaction, which ensures the flexibility and solubility of macromolecules without sacrificing color purity and exciton utilization. The result solution-processed OLEDs exhibit typical near UV emission with spectra peak at 400 nm for the TADF dimer, while the TADF polymer achieves a lower turn on voltage of 3.4 V and high device of 8.5% external quantum efficiency, which represents the best electroluminescence performance among solution-processed near UV-OLEDs. This is the first example to design UV TADF polymer and the result finding will shed light on the further development of enhancing solution-processed UV-OLED performance.