Synthesis of Highly Luminescent Chiral Nanographene

Chiral nanographenes with both high fluorescence quantum yields (phi(F)) and large dissymmetry factors (g(lum)) are essential to the development of circularly polarized luminescence (CPL) materials. However, most studies have been focused on the improvement of g(lum), whereas how to design highly emissive chiral nanographenes is still unclear. In this work, we propose a new design strategy to achieve chiral nanographenes with high phi(F) by helical pi-extension of strongly luminescent chromophores while maintaining the frontier molecular orbital (FMO) distribution pattern. Chiral nanographene with perylene as the core and two dibenzo[6]helicene fragments as the wings has been synthesized, which exhibits a record high phi(F) of 93 % among the reported chiral nanographenes and excellent CPL brightness (B-CPL) of 32 M-1 cm(-1).

Automated summary

In this study, a new design strategy is proposed to achieve chiral nanographenes with high fluorescence quantum yields by helical pi-extension of strongly luminescent chromophores. The synthesized chiral nanographene, with perylene as the core and two dibenzo[6]helicene fragments as the wings, exhibits a record high fluorescence quantum yield of 93% among reported chiral nanographenes and excellent circularly polarized luminescence brightness of 32 M-1 cm(-1).