Fluorene-based novel gold(i) complexes with aggregation-induced emission (AIE) or aggregate fluorescence change characteristics: from green to white emission

Abstract

In this paper, five fluorene-based gold(I) complexes are synthesized and characterized. They exhibit typical aggregation-induced emission (AIE) properties or significant aggregate fluorescence change behaviors. Their thin-film and solid state fluorescence spectra are consistent with the luminescence of all luminogens in DMF–H₂O mixtures with high water content. The emission color changes with different numbers of fluorene units. Among them, it is remarkable that luminogens 4 and 5 emit a bright white light in the thin-film and solid state. In addition, their thin-film absolute fluorescence quantum yields are also investigated. The results indicate the luminogen 4 gold(I) complex, with three fluorene units, exhibits the highest thin-film emission quantum yield, which is up to 65.42%.