How Matrixes Influence Room Temperature Ultralong Organic Phosphorescence: 4-Dimethylaminopyridine vs Carbazole Derivative

How matrixes influence room temperature ultralong organicphosphorescence(RTUOP) in the doping systems is a fundamental question. In this study,we construct guest-matrix doping phosphorescence systems by usingthe derivatives (ISO2N-2, ISO2BCz-1, and ISO2BCz-2) of three phosphorescenceunits (N-2, BCz-1, and BCz-2) and two matrixes (ISO2Cz and DMAP) andsystematically investigate their RTUOP properties. Firstly, the intrinsicphosphorescence properties of three guest molecules were studied insolution, in the pure powder state, and in PMMA film. Then, the guestmolecules were doped into the two matrixes with increasing weightratio. To our surprise, all of the doping systems in DMAP featurea longer lifetime but weaker phosphorescence intensity, while allof the doping systems in ISO2Cz exhibit a shorter lifetime but higherphosphorescence intensity. According to the single-crystal analysisof the two matrixes, resemblant chemical structures of the guestsand ISO2Cz enable them to approach each other and interact with eachother via a variety of interactions, thus facilitating the occurrenceof charge separation (CS) and charge recombination (CR). The HOMO-LUMOenergy levels of the guests match well with the ones of ISO2Cz, whichalso significantly promotes the efficiency of the CS and CR process.To our best knowledge, this work is a systematic study on how matrixesinfluence the RTUOP of guest-matrix doping systems and may give deepinsight into the development of organic phosphorescence.