Near‐Infrared Light‐Emitting Diodes (LEDs) Based on Poly(phenylene)/Yb‐tris(β‐Diketonate) Complexes

Near‐infrared‐emitting electroluminescent (EL) devices using blue‐light‐emitting polymers blended with the Yb complexes Yb(DBM) 3 phen (DBM = dibenzoylmethane), Yb(DNM) 3 phen (DNM = dinaphthoylmethane), and Yb(TPP)L(OEt) (L(OEt) = [(C 5 H 5 )Co{P(O)Et 2 } 3 ] – ) have been studied. EL devices composed of Yb(DNM) 3 phen blended with PPP‐OR11 showed enhanced near‐IR output at 977 nm when compared to those fabricated with Yb(DBM) 3 phen/PPP‐OR11 blends. The maximum near‐IR external efficiencies of the devices with Yb(DBM) 3 phen and Yb(DNM) 3 phen are, respectively, 7 × 10 –5 (at 6 V and at 0.81 mA mm –2 ) and 4 × 10 –4 (at 7 V, and 0.74 mA mm –2 ). The optimal blend composition for EL device performance consisted of PPP‐OR11 blended with 10–20 mol‐% Yb(DNM) 3 phen. A device fabricated using Yb‐(TPP)L(OEt)/PPP‐OR11 showed significantly enhanced near‐IR output efficiency, and future efforts will focus on devices fabricated using porphyrin‐based materials.