Simple and valid strategy for the enhancement of the solid-emissive property of boron dipyrromethenes

Abstract

This manuscript presents the strategy for obtaining solid-emissive properties from the BODIPY dyes. It is demonstrated that the emission properties can be preserved from the aggregation-caused quenching (ACQ) by introducing the phenyl groups into their boron center. We established the synthetic procedures for the introduction of single or dual phenyl groups into the boron center in BODIPYs. The synthesized BODIPYs having single and dual-phenyl groups showed unimodal photoluminescence spectra both in the solution and solid states with sufficient quantum yields. The pristine and the single-phenyl substituted BODIPYs showed similar optical properties in the solution state. In contrast, the dual-phenyl substituted BODIPY provided broad and red-shifted photoluminescence spectrum. Interestingly, the emission property of the dual-substituted BODIPY was recovered not only in the solid state but also in the viscous solvent. It was revealed that the suppression of the molecular motion should play a crucial role in the enhancement of the emission properties of the dual-substituted BODIPY. Furthermore, it is also presented that the steric hindrance by the phenyl groups can inhibit ACQ in the condensed state.