High-efficiency Red Electrofluorescence Devices Employing a Rhenium Complex as Phosphorescent Sensitizer

Efficiencies of up to 7.81 cd/A and brightness of 8843 cd/m² are obtained based on green–yellow phosphorescent material, fac 4, 4′-bi (tert-butyl)-2, 2′-bipyridine Re(CO)₃Cl(Bu ^t bpy)Re(CO)₃Cl] doped into 4,4′-N,N′-dicarbazole-biphenyl (CBP) host. We also fabricate high-efficiency red devices by introduction of (Bu^tbpy)Re(CO)₃Cl as a sensitizer, and the undoped ultrathin layer 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) as fluorescent acceptor. Förster energy of triplet and singlet are efficient due to appropriate overlap between emission spectrum of (Bu ^t bpy)Re(CO)₃Cl and absorption spectrum of DCJTB.