Bowl-Shaped Corannulene Donor-Acceptor Emitter Unlocks Host-Modulated TADF/RTP for Oxygen Sensing

While the study of planar polycyclic aromatic hydrocarbon (PAH) is rich and their properties are well described, the exploitation of curved PAHs, such as corannulene derivatives, is less established. We report the first example of a corannulene derivative, a donor-substituted corannulene, PXZCor, that exhibits thermally activated delayed fluorescence (TADF). In degassed toluene, PXZCor emits bright green TADF, with a delayed fluorescence lifetime, d, of 67.1 μs. As doped films in poly(methyl methacrylate) (PMMA), at room temperature, the delayed emission of PXZCor primarily originates from TADF, as the temperature decreases, phosphorescence gradually becomes the dominant contributor to the delayed emission. In contrast, when PXZCor is doped into the more rigid host, 1,3-bis(N-carbazolyl)benzene (mCP), there is significant delayed emission observed at room temperature that is TADF, and distinct phosphorescence only emerges at temperatures below 200 K. PXZCor can act as a potent O2 sensor using emission intensity and lifetime-based assays. Notably, as a lifetime-based assay, PXZCor is among the most effective TADF compounds reported for O₂ detection down to concentrations as low as 0.01%. These findings highlight the potential of corannulene materials as optoelectronic materials.