Layer-by-layer assembly of luminescent ultrathin films by Mg–Al–Eu LDHs nanosheets and organic ligand with high transparency

• OMTFs were prepared as light-emitting materials.
• The OMTFs were highly transparent, uniform, ordered and ultrathin.
• The thickness and fluorescence emission intensity of the OMTFs could be controlled by the number of deposition cycles.
• The OMTFs were fabricated via layer-by-layer assembly method, this process is simple and economical.

We fabricated a kind of luminescent ordered multilayer transparent ultrathin films (OMTFs) based on inorganic rare earth doped layered double hydroxides (Mg–Al–Eu LDHs) nanosheets and the organic ligand 2-thenoyltrifluoroacetone (TTA) via layer-by-layer assembly method. At the same time, Polyvinyl Alcohol (PVA) aqueous solution was used as intermediate linkers. UV–visible absorption spectroscopy, X-ray diffraction, fluorescence spectroscopy and scanning electron microscopy were introduced to investigate the structure and properties of these films. Surprisingly, the uniformity and the fluorescence emission intensity of OMTFs which utilized polyvinyl Alcohol (PVA) as intermediate linkers are significantly enhanced compared with that of OMTFs without PVA. Herein, it was found that the fluorescence emission intensity of this kind of ultrathin film with PVA displays a monotonic increase as the number of deposition cycles increasing, and further the films which are highly transparent, uniform and ultrathin have potential applications in the optical display devices.