Pure Organic Phosphor Sensitization Based Highly Efficient Electrofluorescence Material.

Pure organic room temperature phosphorescence (RTP) materials are considered as potential candidates for replacing precious metal-based complexes to fabricate highly efficient organic light emitting devices (OLEDs). However, applications of the reported RTP materials in OLEDs are seriously impeded by their low photoluminescence quantum yields (PLQYs) in thin film state. To overcome these obstacles, we established a new strategy to construct highly efficient OLEDs based on pure organic RTP material sensitized fluorescence emitter by selecting benzimidazole-triazine molecules (PIM-TRZ), 2,6-di(phenothiazinyl)naphthalene (s-DPTZN) and 5,6,11,12-tetraphenylnaphthacene (rubrene) as host, phosphor sensitizer and fluorescent emitter, respectively. The perfect combination of host, phosphorescent sensitizer and fluorescent emitter in the emitting layer ensure the outstanding performance of the devices with external quantum efficiency (EQE) of 15.7%, which sheds light on a new avenue for the construction of cost-effective high-performance OLEDs based on classic fluorescence emitters.