Photo-facilitated aggregation and correlated color temperature adjustment of single component organic solid state white-light emitting materials

A color tuning strategy has been developed based on the N-alkylation of the terminal 4-pyridyl groups of 4′-(4-pyridyl)-2,2′:6′,2′″-terpyridine molecule to adjust the desired properties of luminescence materials. The fluorescence emission of the parent chromophore can be successfully extended into the long-wavelength region in solution, and an unprecedented aggregation facilitated by light irradiation occurs in n-butanol to result in almost white-light emission due to the generation of dual-color fluorescence. By controlling solid-state molecular structures, four homologous single-crystal materials with intra- and intermolecular charge transfer synergy-induced dual emissions, which render not only ideal white light chromaticity, but also tunable correlated color temperature ranging from warm-white to cool-white light, have been obtained.