Pyrene-Based Triphenylamine Light-Harvesting Materials with Related Structure-Property Relationships

In this study, a series of novel pyrene-based triphenylamine (TPA) and its derivatives (4,4'-dimethoxytriphenylamine, TPA-OMe) were synthesized from a newly developed chemical intermediate, bromopyrene. This approach provides a unique opportunity to systematically investigate the effects of the substituent number and position on their photophysical properties. The results demonstrate that the molar absorption coefficients and fluorescence quantum yields of these pyrene derivatives significantly increase with the number of TPA or TPA-OMe units, exhibiting excellent light-harvesting antenna characteristics. The introduction of TPA or TPA-OMe units at the 1,6-positions induces a blue shift in fluorescence while having minimal impact on the absorption bands in solution. Single-crystal X-ray diffraction analysis and solid-state fluorescence spectroscopy reveal that the steric hindrance effect of TPA-OMe groups suppresses complex intramolecular interactions, thereby preserving the antenna properties of these derivatives. Furthermore, concentration-dependent and time-resolved fluorescence spectra provide insights into the molecular aggregation behavior and energy transfer processes. The findings of this study offer a new molecular strategy for designing efficient artificial light-harvesting antenna systems and lay a theoretical foundation for their applications in energy conversion.