Theoretical studies on thermally activated delayed fluorescence mechanism of a series of organic light‐emitting diodes emitters comprising 2,7‐diphenylamino‐9,9‐dimethylacridine as electron donor

According to one experimentally reported thermally activated delayed fluorescence (TADF) emitter (AcDPA‐2TP), two new molecules (AcDPA‐2PP and AcDPA‐TPP) have been designed theoretically to probe into the effect of different acceptor strengths on their TADF mechanisms. In this work, the rates of reverse intersystem crossing (kRISC) of the three targeted molecules were calculated by the semiclassical Marcus rate expression. The present results demonstrate that the kRISC rate of AcDPA‐2PP is estimated to be 5.56 × 106 s−1, about twice larger than that of AcDPA‐2TP (2.63 × 106 s−1), and especially AcDPA‐TPP is found to exhibit the largest kRISC value (6.97 × 106 s−1) among the three molecules. Considering that AcDPA‐2TP has been observed to be an efficient TADF emitter, our newly designed two molecules AcDPA‐2PP and AcDPA‐TPP are also expected to be potential TADF materials. © 2018 Wiley Periodicals, Inc.