In situ encapsulation of coumarin/fluorescent bleacher/carbazole derivatives@Eu MOF materials for white light-emitting diodes

Abstract

Metal-organic frameworks (MOFs), characterized by their high porosity, large specific surface area, and tunable pore structures, have emerged as promising host materials for advanced functional applications. In this study, two organic dyes, fluorescent bleacher (CBS) and coumarin (C6), exhibiting blue and green fluorescence, respectively, were co-encapsulated into europium (Eu)-based MOFs, where Eu³⁺ served as the central metal to introduce red emission. The ligand employed was 9-butylcarbazole-2-carboxylhydrazide thiophene (Cz). A white fluorescent powder, coumarin/fluorescent bleacher/carbazole derivatives@Eu (C6/CBS/Cz@Eu), was synthesized using an in situ encapsulation method. The C6/CBS/Cz@Eu was incorporated into PVA to prepare a film. The resulting C6/CBS/Cz@Eu film demonstrated a high-quality white light emission under excitation by commercial 400 nm light-emitting diode (LED) chips, achieving ideal Commission Internationale de l'Éclairage (CIE) chromaticity coordinates of (0.34, 0.35) and a correlated color temperature (CCT) of 5267 K. This strategy offers a versatile and scalable method for the design and fabrication of white light-emitting materials, beneficial for the development of next-generation white light-emitting diode (WLED) technologies.