Electroluminescent room temperature columnar liquid crystals based on bay-annulated perylene tetraesters†‡

Abstract

Room temperature columnar liquid crystals with a wide thermal range, based on bay-annulated perylene tetraesters are reported. Through the incorporation of heteroatoms like N, S and Se in the bay position of the perylene tetraester the emission behavior in the solution state has been effectively tuned, where the N, S and Se-annulated derivatives showed bright green, blue and weak yellowish green fluorescence. The electroluminescence behavior of these compounds has been explored as emissive layers in organic light emitting diodes. Further, a remarkable improvement in the emission was achieved, when these molecules were doped in a matrix of polyvinyl carbazole (PVK), which is due to a combination of Förster resonance energy transfer from the host to the guest and charge carrier trapping in the emissive layer.