Amplified Circularly Polarized Electroluminescence Behavior Triggered by Helical Nanofibers from Chiral Co‐assembly Polymers

Abstract Two chiral binaphthyl polymers ( R / S ‐P1 and R / S ‐P2 ) with different dihedral angles of the binaphthyl moiety were chosen as chiral inducers to construct chiral co‐assemblies with an achiral pyrene‐naphthalimide dye ( NPy ) and then acted as the emitting layer (EML) of circularly polarized electroluminescence (CP‐EL) devices. The anchored dihedral angle of R / S ‐P2 not only exhibited the enhanced chirality signal, but also had a strong chirality‐inducing effect on the achiral NPy dye in the chiral co‐assembly ( R / S ‐P2) 0.6 ‐(NPy) 0.4 . After annealing at 120 °C, the CPL signal (| g em |) of ordered helical nano‐fibers ( R / S ‐P2) 0.6 ‐(NPy) 0.4 was amplified to 5.6×10 −2 , which was about 6‐fold larger than that of ( R / S ‐P1) 0.6 ‐(NPy) 0.4 . The amplified g em value of ( R / S ‐P2) 0.6 ‐(NPy) 0.4 was due to the formation of a helical co‐assembly through the strong π–π stacking interaction between the R / S ‐P2 and the achiral NPy . This kind of ordered helical nano‐fibers ( R / S ‐P2) 0.6 ‐(NPy) 0.4 acted as the EML of CP‐OLEDs, and achieved an excellent CP‐EL performance (| g EL |=4.8×10 −2 ).