The influence of aggregation behavior of novel quinophthalone dyes on optical and thermal properties of LCD color filters

• Four novel yellow quinophthalone dyes were synthesized for LCD color filters.
• Dye aggregation influenced the particle size of molecules after spin-coating.
• Dyes can be re-aggregated with evaporation of solvents after the baking process.
• Dye aggregation can deteriorate the properties of dye-based LCD color filters.
• The modification of dye structure can relieve the aggregation of dye molecules.

Four novel yellow quinophthalone dyes were designed and synthesized in order to examine the influence of aggregation behavior on the optical and thermal properties of liquid crystal display color filters. These synthesized dyes showed different absorption spectra and thermogravimetric behavior according to their characteristic structures. When the synthesized dyes were dissolved in industrial solvent-binder composites and spin-coated onto a glass substrate, re-aggregation or migration of the dye molecules were shown in the field emission scanning electron microscopy images after the baking processes. The degree of aggregation depended on the structures of the dyes and affected various properties of the color filters. The transmittances of the color filters decreased as the aggregation of the dye molecules increased. The contrast ratios of the color filters also reduced with aggregation after the baking process. The color difference values of the color filters increased remarkably with more aggregation as the baking process was repeated.

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