Study On Preparation And Fluorescence Properties Of Lanthanum And Samarium Co-doped Rare Earth Complexes

When the rare earth complex is stimulated by the outside world,it will absorb energy,and go through the transition process of ground state? excited state? ground state,so that the prepared rare earth complex has a strong fluorescence emission intensity,and in this process,it will release energy in the form of light.The rare earth complexes prepared are largely used in magnetic,optical and electrical fields mainly because of the unique properties of the rare earth ions contained in the complexes.Therefore,in recent years,increasing the emission intensity of rare earth center ions has attracted the attention of many researchers.In this paper,the use of inert rare earth elements to enhance the luminescence properties of other rare earth elements to improve the fluorescence intensity of the complex.Then polyacrylamide and polymethyl methacrylate were used as the matrix to prepare a series of composite materials,and their characterization.(1)Because the ligand has an important role in rare earth,it is also very important to choose the right ligand.Firstly,the first ligand was screened with benzoic acid(BA),fumaric acid(FA),DL-malic acid(DL-MA)and stearic acid(SA)with Sm3+as the central ion.Sm(BA)3Phen,Sm(FA)3Phen,Sm(DL-MA)3Phen and Sm(SA)3Phen were prepared.Benzoic acid is the best ligand,and the fluorescence intensity of Sm(BA)3Phen rare earth complex prepared from it is the strongest.Then,the collaborative ions were screened.The collaborative ions were potassium sulfate,sodium sulfate,lanthanum chloride and barium sulfate,respectively,to prepare rare earth complexes for the screening of collaborative ions.The results showed that the fluorescence intensity of rare earth complexes prepared was the strongest when the collaborative ion was La3+·.With screening good first ligands benzoic acid.Finally,the selected ligand benzoic acid,the collaborative ion La3+,and the addition of o-phenanthroline were used to eliminate the influence of water molecules on the rare earth complex to prepare the rare earth complex with excellent fluorescence performance,and a series of characterization were carried out.The results show that rare earth lanthanum elements and samarium element can be a good bonding,and ligand was also involved in the reaction,and then proved by fluorescence spectrum analyzer sensitization effect of lanthanum elements,as well as the main light condition is the result of the transition of samarium ion.The characteristic fluorescence emission peaks of Sm3+correspond to the transitions of 4G5/2?6H5/2(564 nm),4G5/2?7H7/2(599 nm)and 4G5/2?6H9/2(645 nm),respectively.(2)LaSm(BA)3Phen/PAM was successfully synthesized by selecting polyacrylamide as a polymer material and combining the above prepared LaSm(BA)3Phen with non-covalent bonding method.Through a series of characterization,the results show that the luminescence properties of the composite material LaSm(BA)3phen/PAM synthesized with polyamide as the matrix are obviously better than that of the lanthanum and samarium rare earth complex LaSm(BA)3phen,and the characteristic emission peaks of Sm3+ are as follows:4G5/2?6H5/2 transition at 564 nm,4G5/2?7H7/2 transition at 599 nm and 4G5/2?6H9/2 transition at 645 nm.The luminescence properties of the copolymer LaSm(BA)3Phen/PAM are better than that of LaSm(BA)3Phen.Finally using the single factor experiments show when lanthanum and samarium 5:5 ratio of mole fraction.Finally,the single factor experiment showed that when the molar fraction ratio of lanthanum to samarium was 5:5 and the addition of rare earth complex was 0.6%,the fluorescence intensity of the prepared hybrid material was the strongest.The single factor experiment and the Design-Expert 10.0.7 Trial software were used to analyze the two factors affecting the fluorescence intensity,know that when the reaction time of 5 h,the temperature is 60?,the stirring speed is 600 r/min,prepared composite has the strongest fluorescence intensity(3)Using polymethyl methacrylate as the matrix,the above prepared LaSm(BA)3Phen/PMMA was composite by non-covalent bonding method,and the LaSm(BA)3Phen/PMMA composite material was successfully synthesized.Through a series of characterization of the composite material,the results are as follows:the Sm3+ compound charge transition at 350 nm,strongest and fluorescence intensity at that point.But 364 nm(6H5/2?(4K,4L)17/2),379 nm(6H5/2?(4D,6P)15/2),393 nm(6H5/2?4K11/2),420 nm(6H5/2?4M19/2),467 nm(6H5/2?4I13/2)all belong to the characteristic excitation peak of Sm3+.And in LaSm(BA)3Phen/PMMA excitation spectrum of the intensity of excitation band.There has been a significant change,but mainly in the emission spectra appear three obvious characteristlc peak,and is located at 564 nm,respectively 4G5/2?6H5/2 transition is located at 564 nm,4G5/2?7H7/2 transition is located at t 599 nm and the fluorescence intensity of the strongest is located at 645 nm of 4G5/2?6H9/2 transition.And with methyl methacrylate as the substrate preparation by the fluorescence properties of the composite material is superior to the preparation of rare earth complexes.By comparing them,we found that the fluorescence performance of LaSm(BA)3Phen/PAM is better than that of LaSm(BA)3Phen/PMMA.