Room-Temperature Phosphorescence of Pyrene Using Perovskite as a Triplet-Sensitizing Matrix and Oxygen Barrier

To realize the formation and transfer of triplet excited states in hybrid organic–inorganic materials, material designs that facilitate efficient triplet sensitization and suppress molecular excited state deactivation are imperative. In this study, we demonstrated the efficient formation of molecular triplet excited states via through-space triplet energy transfer (TET) in a perovskite nanocrystal (PNC)—pyrene (Py)—composite film. Uniform dispersion of Py as an organic acceptor within the PNC matrix facilitated effective TET, enabling room-temperature Py phosphorescence emission with an average lifetime (44.7 ms). The TET process exhibited an efficiency of 22%, and the oxygen barrier properties of the PNC matrix suppressed oxygen quenching, allowing retention of Py phosphorescence even under ambient conditions. The proposed simple and effective material design strategy for extending the functionalities of organic acceptor molecules through controlled interface interactions can be applied in triplet–triplet annihilation upconversion and photocatalysis.