Synthesis, optical properties and crystal structures of carbazole end-capped phenylene ethynylene blue light-emitting materials

A class of highly fluorescent and stable carbazole end-capped phenylene ethynylene compounds have been synthesized and characterized. They show high extinction coefficients of absorption (λ_max^abs = 33 0 - 34 0 nm) and quantum yields of fluorescence (λ_max^em = 393 - 396 nm; Φ_F=0.52-0.73) in dichloromethane. The solid state absorptions and emissions are significantly red-shifted from the dilute solution ones (λ_max^abs = 358 - 375 nm; λ_max^em = 396 - 458 nm). Their photoluminescent properties and crystal structures have been investigated with the aim of providing a basis for elucidating the structure-physical property relationships. These data indicate their potential use as blue-emitting materials in organic light-emitting diodes (OLEDs).