fluorescent pigments component structural features

fluorescent pigments are compounds having a specific structure, its structural features are the following three points:
(1), the molecule contains a fluorescing group, such as carbonyl, nitrogen nitrogen double bond, carbon and nitrogen double bond.
(2), containing molecules to help color group. Auxochrome make fluorescence spectral redshifts and increase efficiency, such as primary amine, secondary amine, a hydroxyl group, an ether bond, an amide group.
(3), comprising a rigid planar structure of the molecule of the conjugated π bond. Conjugated molecular systems within the larger plane of stronger fluorescence intensity higher. Some can improve the conjugation of factors that can improve the fluorescence efficiency,photoluminescent pigments and fluorescence wavelength shift to longer wavelengths.