Construction Of Photoresponsive Intelligent Lanthanide Hybrid Luminescent Materials

Because of their intriguing optical properties,such as narrow emission bands,large Stokes shift,high quantum yield,and long excited lifetime,lanthanide have been widely applied in light-emitting devices,biological imaging,detection and sensing.In the past few decades,many matrix including zeolite,clay,and metal organic framework(MOFs)have been introduced to design and develop lanthanide hybrid luminescent materials.On the other hand,compared to temperature,humidity,p H,redox and other external stimuli,light irradiation is able to remotely trigger action cleanly with high precise control,which have promising applications in information transmission,data storage and anti-counterfeiting,thus it is highly desirable to develop novel photoresponsive lanthanide hybrid luminescent materials.Herein,we design and construct two light responsive intelligent lanthanide hybrid luminescent materials as follow:(1)We prepared a new lanthanide complex modified with cyclodextrin(CD).Then the azobenzene/?-CD inclusion complex was obtained by introducing guanidine modified azobenzene guest molecule,which was further used as“molecular glue”to cross-link sodium polyacrylate exfoliated laponite nanosheets(SPLNs)into luminescent supramolecular hydrogel.Reversible gel-sol phase transformation was successfully achieved by alternating the exposure to UV/visible light.Moreover,there is no overlap between photoisomerization wavelength of azobenzene(365-450 nm)and excitation emission wavelength of the lantanide complexes,thus rendering hydrogels luminescent and photoresponsive simultaneously.(2)We reported an approach to construct a smart lanthanide luminescent material with potential of information protection by loading the solid state photoresponsive luminescence ON-OFF switch into MOFs.Because the diarylethene of close-form(OF-DAE)showed no absorption in the long wavelength range above 400 nm,it exhibited the characteristic color and brightness of Eu³⁺ions,as no fluorescence resonance energy transfer(FRET)occurred.After irradiated with 300 nm UV light,DAE switched from open-form(OF-DAE)to close-form(CF-DAE)with a new absorption band in the range of 500-700 nm,which was perfectly overlapping with the emission spectrum of ZJU-88 host and meeting the condition of FRET,hence the fluorescence was quenched.Subsequently,we demonstrated the potential application of this MOFs in the development of anti-counterfeiting materials.