Synthesis and luminescent properties of carbazole end-capped phenylene ethynylene compounds

A class of highly fluorescent and stable carbazole end-capped phenylene ethynylene compounds have been synthesized and the comparative photophysical studies are presented. These compounds exhibit intense violet-blue emission in CH2Cl2 solution (λmaxem≈383–420 nm, ΦF≈0.36–0.88, τF≈1.14–6.63 ns), and show a red-shifted emission in the solid state relative to that in solution. The extent of the shift is highly dependent on the nature of the substituents and the π-conjugation length of phenylene ethynylene component. Their photophysical properties and structural characterization have been investigated with the aim to provide a basis for elucidating the structure–property correlations and developing new blue-emitting materials in organic light-emitting diodes (OLEDs).