Polymers with Bipolar Carrier Transport Abilities for Light Emitting Diodes

Efficient and stable polymer light emitting diodes (LEDs) have recently been extensively pursued. To achieve efficient LED performance for a single layer device, a polymer with bipolar carrier transport abilities and high-luminescence quantum yields is desired. We envision that if an emissive polymer combines both electron and hole transporting segments, it could possess comparable bipolar carrier transport ability. In this paper, we report two oxadiazole-containing poly(phenylenevinylenes) (PPVs). An oxadiazole unit is introduced into the polymer backbone to improve the electron injection/transport properties. The oligo(phenylenevinylene) segments function as both hole transporter and emitter. In one polymer, carbazole is introduced in the side chain to improve the hole tranport properties. The syntheses and device evaluations of these polymers are reported.