Polymer light‐emitting diodes with doped hole‐transport layers

Abstract

Abstract We demonstrate a solution processed bi‐layer PLED based on poly(p‐phenylene vinylene) derivatives using orthogonal solvents. To lower the voltage drop the hole transport layer (HTL) based on poly[2,5‐bis(2′‐ethylhexyloxy)‐ co ‐2,5‐bis(butoxy)‐1,4‐phenylenevinylene] (BEH/BB‐PPV (1:3)) is doped with tetracyano‐tetrafluoro‐quinodimethane (F4TCNQ). The conductivity of BEH/BB‐PPV (1:3) was observed to increase by two orders of magnitude upon doping with F4TCNQ. The doped HTL was observed to lower the operating voltage of a double layer PLED, but suffers from additional quenching by the dopant at higher voltages due to the lack of an electron blocking functionality.