New Conjugated Electroluminescent Triphenylamine-Containing Polymers with Side-Chain Pyridin-2-ylimidazo[l,5-a]pyridine Groups for Polymer Light-Emitting Diodes

摘要

In recent years, light emitting diodes (LEDs) based on conjugated polymers have attracted considerable attention of researchers owing to their promising potential as new-generation full-color flat-panel displays [1—6]. An important problem that still remains unsolved is improving of the external quantum efficiency (EQE) of polymeric light-emitting diodes. The principle of operation of thin-layer LED structures is based on electroluminescence (EL) caused by radiative decay of excitons arising upon recombination of the electrons and holes injected from opposite electrodes into the polymer layer. Perfect conditions for producing intense EL and reaching high EQE values for a polymer are high electron—hole conductivity of the medium (that is, high mobility of charge carriers) and maintenance of the balance of injected charge carriers of different signs from the opposite electrodes into the material bulk. The mobilities of electrons and holes should not differ considerably.