Fluorogels: A one pot approach on photoluminescent glasses doped with covalently bound organic chromophores

The synthesis of strongly fluorescent silica alcogels and glasses containing covalently bound thienyl arenes as organic chromophores and their luminescence properties are described. The rational design of a white light emitting gel is explained with respect to the principle of additive color mixing. CIE coordinates for the different emitters have been determined, illustrating how mixtures of chromophores can create different shades of white to off-white light. 5,8-Dithien-2-ylquinoxaline, which was embedded in one of the alcogels, was found to be a white light emitting molecule itself. For a representative fluorogel incorporating an acridone dye, quantum yield and excitation measurements were conducted on silica samples incorporated in layers of PMMA. This revealed absolute quantum yields of 5.6–7.4% for the analyzed species at concentrations of 10 weight% of silica. With respect to the facile synthesis of the glasses and the extremely low dye concentrations of approximately 6 × 10−6 mol g−1, these new hybrid compounds pave the way towards the use of enhanced metal-free hybrid emitters in various coating and lighting applications.

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► Highly fluorescent silica containing linked di(thien-2-yl)arylenes are presented.
► The obtained xerogel monoliths possess a glass-like morphology.
► The luminescence color according to CIE index can easily be modified.
► A 5,8-dithien-2-ylquinoxaline derivative in SiO2 matrix emits white light.