Photoactive Hybrid Polymer Films Incorporated with Lanthanide Complexes and ZIF-8 for Selectively Excited Multicolored Luminescence

A series of photoactive polymer hybrid films fabricated with both lanthanide complexes and ZIF-8 [zeolite imidazole framework, a kind of metal organic framework, Zn(MeIM)(2), MeIM = 2-methylimidazole] was prepared. ZIF-8 and the lanthanide complexes Ln-L [Ln = Eu, Tb; L = AA (acetylacetonate), phen (1,10-phenanthroline), TAA (trifluoroacetylacetonate), TTA (trifluoroacetylacetonate)] were assembled with the the monomers 4-vinyl pyridine (VPD) and ethylene-methyl acrylate (EMA), forming the final hybrid polymer films after initiation with benzoyl peroxide (BPO). The products are are indicated as PEMA-PVPDLn-L/ZIF-8 [PEMA-PVPD: copolymer of poly 4-vinyl pyridine (PVPD) and polyethylene-methyl acrylate (PEMA)]. The SEM images of these hybrid films indicate homogeneous dense packing and a high degree of coverage of the crystals on the ITO glass. The luminescent behavior of all the hybrid films was studied in detail. Discrete luminescence of the ZIF-8 unit and the lanthanide complexes was observed in which energy coupling between the two emissive centers does not exist. Therefore, by selectively exciting these hybrid films with different wavelengths, the luminescence colors of them can be tuned from blue (for ZIF-8) to red (for Eu3+), green (for Tb3+), yellow (for Eu3+/Tb3+) and even to white by integrating the emission of both Eu3+/Tb3+ into the polymer unit (PEMA-PVPD). These results are useful and have potential application in optical devices for displays or encoding.