氨基多糖/稀土金属复合光功能材料的制备及应用

[Objective]Among amino polysaccharides,carboxymethyl chitosan(CMCh)is a kind of non-traditional luminous material with neither aromatic nor conjugated structure.It can coordinate with rare earth ions through rich functional groups,and as a kind of biomass macromolecular ligand,it can transfer its absorbed energy to rare earth ions,which makes it emit strong characteristic fluorescence.In this paper,the coordination of CMCh as ligand and Eu3+,Tb3+ and Eu3+/Tb3+ as central ions and their luminescence properties were studied.The mechanism of energy transfer from biomass macromolecules as ligands to central lanthanide ions was investigated through characterization,and the multifaceted application was expand.[Method]CMCh-Eu3+ fluorescent aerogel,CMCh-Tb3+ fluorescent probe and CMCh-Eu3+/Tb3+ multicolor fluorescent powder were prepared in green mode.It was characterized and applied to the adsorption and detection of acid gas,the sensitive response of Cu2+ and the preparation of photoluminescent multicolor LED lamps.[Result]CMCh-Eu3+ exhibits opposite fluorescence response to HCl gas and HAc gas.HCl quenches its fluorescence while HAc enhances it.CMCh-Tb3+ can detect the Cu2+ sensitively in aqueous solution without interference,and the fluorescence intensity of the probe at 553 nm shows a good linear relationship with the concentration of Cu2+,and has a short response time and good anti-interference.CMCh-Eu3+/Tb3+ is to control the color of the fluorescent powder by regulating the ratio of two lanthanide ions.After curing different proportions of CMCh-Eu3+/Tb3+ powder on the UV chip,photoluminescent LED lights with different luminous colors and similar WLED lights are prepared.[Conclusion]The fluorescence quenching effect of HCl gas is due to the destruction of CMCh-Eu3+ coordination environment by HCl,which cuts off the sensitization path of the ligand to the central ion,while the fluorescence enhancement effect of HAc is due to the substitution of H2O molecules in the coordination.The quenching effect of Cu2+ on the probe is partly due to the static quenching caused by Cu2+ destroying the synergistic effect between CMCh and Tb3+,and partly due to the dynamic quenching caused by the collision between Cu2+ and the probe,which causes some excited electrons to undergo non-radiative transition and intra-system conversion.The energy transfer of the CMCh to Eu3+ and Tb3+ is based on the fluorescence resonance between the triplet level of the ligand and the excited state level of the lanthanide ion.However,due to the small energy difference,part of the energy transferred to Tb3+ is transferred back to the ligand CMCh,and part of the energy transferred to Eu3+.Thus,multicolor luminescence of CMCh-Eu3+/Tb3+ is realized.