Photostable cyano-substituted boron-dipyrromethene dye as green emitter for display and illumination applications

An ink formulation, comprising

• (i) an organic fluorescent dye comprising a compound of formulae (I.a), (I.b), and/or (I.c)
• wherein
• R1, R2, R3, R5, R6, and R7, are independently H, C1-C20-alkyl, or C6-C14-aryl-C1-C10-alkylene, the aryl moiety in C6-C14-aryl-C1-C10-alkylene being optionally substituted by k independent substituents R9,
• R4a and R4b are independently fluorine, chlorine, cyano, or OR10,
• R8a is C1-C20-alkyl,
• R8b is C1-C20-alkyl, and
• R8c is C1-C20-alkyl, C6-C10-aryl, or C6-C10-aryl-C1-C10-alkylene, aryl moieties being optionally substituted by k independent substituents R9,
• k is 1, 2, 3, 4, 5, or 6;
• R9 is C1-C10-alkyl, C1-C10-alkoxy, CN, halogen, phenyl, or phenoxy, and
• R10 is C1-C10-alkyl or hydroxy-C1-C10-alkyl;
• (ii) a photo-curable or thermally curable binder;
• (iii) optionally, a photoinitiator, a photoacid-generator, a reactive monomer, and/or a thermal radical initiator;
• and
• (iv) optionally, a further organic fluorescent colorant different from the compound of formulae (I.a), (I.b), (I.c), an organic solvent, a dispersant, a surfactant, and/or a light scattering agent.