Thermal stability of ZnO nanoparticle bound organic chromophores

•Organic optical dyes prepared as thermally nanoparticle composites.•Thermal Stability shown up to 300 °C.•Dye-nanoparticle composites prepared by electrochemical deposition.•Dye-nanoparticle composite demonstrate enhanced photostability in laminate.

Thermally stabilized metal-organic chromophores have been generated through an electrochemical oxidation of zinc metal to form a ZnO-chromophore nanomaterial. The chromophores are surface bound to ZnO by a polar covalent metal-to-chromophore bridge which minimizes thermal degradation pathways of the organic molecule. The binding occurs between the Zn and carboxylic acid functional groups on the organic chromophore as confirmed using IR spectroscopy monitoring the loss of the COO− peak at 1720 cm−1. The new composite material demonstrates a thermal stability up to 300 °C based on the results of TGA/MS and DSC. The photostability of these materials in either the solution or solid state was monitored using UV/Vis/NIR spectroscopy. When incorporated into a polymer composite there is a dramatic increase in photo-stability compared to the pure chromophore or the metal-chromophore nanomaterial.

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