Organic Long Persistent Luminescence from a Thermally Activated Delayed Fluorescence Compound (dataset)

Organic long persistent luminescence (OLPL) is one of the most promising methods for longlived emission applications. However, present room-temperature OLPL emitters are mainly based on a bi-molecular exciplex system which usually needs an expensive small molecule such as PPT as the acceptor. In this study, we designed a new TADF compound, CzPhAP, which also shows OLPL in many well-known hosts such as PPT, TPBi and PMMA, without any exciplex formation and its OLPL duration reached more than 1 hour at room temperature. Combining the low cost of PMMA manufacture and flexible designs of TADF molecules, pure organic, large scale, color tunable and low-cost room temperature OLPL applications become possible. Moreover, we found that the onset of the 77 K afterglow spectra from a TADF emitter doped film is not necessarily reliable for determining the lowest triplet state (T1) energy level. This is because in some TADF emitter doped films, optical excitation can generate charges (electron and holes) that can later recombine to form singlet excitons during the phosphorescence spectrum measurement. The spectrum taken in the phosphorescence time window at low temperature may consequently consist of both singlet and triplet emission