Intercalation Assembly And Photofunctional Investigation Of Luminescent Lanthanide Ions-doped Layered Lutetium Hydroxide Hybrid Materials

Layered rare-earth hydroxides（LRHs）is a kind of two-dimensional layered materials built up from cationic layers of rare earth hydroxide and anionic interlayer species,which are stacked in an alternating sequence.LRHs combine the unique luminescent properties of rare-earth ions with rich intercalation chemistry behaviors that can be easily modified and functionalized,and are of great significance in a wide range of optics,catalysis,biomedicine and other fields.Considering that Lu³⁺with no fluorescence characteristics,layered lutetium hydroxide（LLu H）was synthesized as a matrix by hydrothermal method.The lanthanide Tb³⁺,Eu³⁺and Ce³⁺ions were doped as green,red and blue luminescence centers,respectively.To enhance and improve the luminescence properties of the LRHs,a series of organic guests were intercalated and assembled with LRHs by ion exchange reactions.The organic guests included benzoic acid,2-fluorobenzoic acid,p-toluic acid,4-methoxybenzoic acid,p-phthalic acid（TA）,1,2,4,5-benzenetetracarboxylic acid（BTCC）,salicylic acid（SA）,dodecyl sodium sulfonate and ibuprofen（IPF）.The structure and luminescent properties of the assemblies were investigated by X-ray diffraction,scanning electron microscopy,infrared spectroscopy,elemental analysis,thermogravimetric analysis,UV-Vis spectroscopy and photoluminescence characterisation.The results showed that the fluorescence performance of layered lutetium terbium hydroxide（LLu H:Tb）intercalated with TA,BTCC and SA,and layered lutetium europium hydroxide（LLu H:Eu）intercalated with TA and BTCC were significantly improved.The above samples could be exfoliated to colloidal nanosheets for the preparation of luminescent controlled colloidal solutions and organic/inorganic luminescent composite films.The layered lutetium cerium hydroxide（LLu H:Ce）nanosheets were used as blue light source to achieve white light emission by blending with LLu H:Tb and LLu H:Eu nanosheets.The IPF sensitized LLu H:Tb showed tremendously enhanced green luminescence and the IPF modified LLu H:Tb nanosheets exhibited excellent fluorescence recognition for Cu²⁺ions in aqueous solutions.The hybrid system may be potentially used in the fluorescent sensing for the detection of metal Cu²⁺ion.Additionally,the LLu H:Eu materials with inorganic NO₃^-and WO₄^2-ions intercalation were heat-treated,and the luminescence of Eu³⁺was greatly enhanced while maintaining the layered structure.Finally,the LRHs/polymer luminescent composite films were constructed based on the high compatibility of LRHs with polymer.The work will be definitely to promote the development and device application of LRHs optical functional materials.