Thermally Activated Delayed Fluorescence Polymer Emitters with Tunable Emission from Yellow to Warm White Regulated by Triphenylamine Derivatives

By virtue of electron-rich structure, relatively low electronic band gap, and strong blue fluorescence emission, triphenylamine derivatives (TPAs) can serve as effective host units for the π-conjugated thermally activated delayed fluorescence (TADF) polymer. In this work, we designed and synthesized two kinds of dual-emission TADF polymers, PTDP-5 and PTDP-10, in which the TPAs act as the host unit and blue light emitter simultaneously, and the alkylated TADF small molecule, 2-(10H-phenothiazin-10-yl) dibenzothiophene-S,S-dioxide, serves as an orange-yellow light emitter. It is proved that the TADF characteristics can be inherited by polymers effectively from TADF small molecules. By regulation of the content of TPA moieties, the emission colors of polymers can also be conveniently tuned from yellow to warm white light. The fabricated polymer light-emitting diodes (PLEDs) show an EQEmax of 7.1% with Commission Internationale de l’Eclairage(CIE) coordinates of (0.42, 0.33) for PTDP-5 and an EQEmax of 4.8% with CIE coordinates of (0.46, 0.41) for PTDP-10.