Properties of Dual Emissive Dendrimers Based on ThermallyActivated Delayed Fluorescence Dendrons and a Phosphorescent Ir(ppy) ₃ Core

Dual emission light-emitting dendrimers composed of phosphorescent fac-tris[2-phenylpyridyl]iridium(III) [Ir(ppy)3] cores and thermally activated delayed fluorescence-based (TADF-based) dendrons have been prepared. The TADF-based are designed to green or blue emission. show solvatochromism, with the switching between phosphorescence TADF depending on medium in which measurement is undertaken. Time-dependent photoluminescence (PL) spectra measurements that can act as an energy pool for from core. PL quantum yields (PLQYs) found be strongly dependent dielectric constant solvent, ranging high 76% low 0.3%. Neat films relatively balanced hole electron mobilities order 10–6 cm2 V–1 s–1, bilayer organic diodes (OLEDs) containing neat emissive layers having a maximum external efficiency (EQE) 4.7% film PLQY 12%. Finally, solution processed OLEDs fabricated using 0.4 mol% blended 9-[3-(9H-carbazol-9-yl)phenyl]-9H-carbazole-3-carbonitrile result EQEs 9.8% 15.1% dendrons, respectively.