Study On Synthesis And Photoluminescence Of Er³⁺-doped LDH

The present work is.to study the synthesis and photoluminescence of Er3+ doped layered double hydroxides(LDHs),and the IR emissions of Er3+ doped hydrocalumite response to citric acid molecule.Then,the synthesis and photoluminescence of Er3+/Tb3+co-doped MgAl-LDH have been investigated,and the research results are followed as:1.Using CaCl2,AlCl3·6H2O,and ErCl3 solid as reactants,a series of Er3+-doped hydrocalumite with different Ca2+/(A13++Er3+)molar ratios have been synthesized via co-precipitation method in ethanol/water media.Compositional and structural analyses reveale that the Er3+-doped hydrocalumite preserves the layered structure as the Ca2+/(Al3++Er3+)molar ratio is between the 0.83 and 1.43.All the Er3+-doped hydrocalumite are monoclinic symmetry despite their different cell parameters.Photoluminescent spectra show strong infrared emissions at 720,780,and 850nm for all the Er3+-doped hydrocalumite.2.The IR emissions of Er3+-doped hydrocalumite response to sodium citrate with the concentrate of 0.01,0.02,0.03,0.04,0.05,0.1,0.2,0.4,and 0.6 mol·L-1 have been examined.It was found that the Er3+-doped hydrocalumite kept monoclinic structure after it was exposed to sodium citrate solution with concentrate of 0.01-0.6 mol·L-1.Meanwhile,the IR emissions of the Er3+-doped hydrocalumite changed slightly as it was exposed to 0.01,0.02,0.03,and 0.04 mol-L-1 sodium citrate solution,respectively.However,the infrared emissions sharply decreased when the concentrate of sodium citrate increased to 0.05 mol·L-1.Further,the decreased infrared emissions hardly changed whilst the concentrate of sodium citrate rose from 0.05 to 0.6 mol·L-1.3.A series of Er3+/Tb3+co-doped-MgAl-LDH with different Er3+/Tb3+molar ratios,kept Mg2+/(A13++Er3++Tb3+)molar ratio of 2.0,have been synthesized by hydrothermal method.Results suggested that the introduction of Er3+and Tb3+did not damage the structure of host,and all the sample retained layered structure of LDH.Moreover,the emissions attributed to Er3+and Tb3+appeared in the emission spectra of the Er3+/Tb3+co-doped-MgAl-LDH,and the emissions due to Tb3+gradually decreased with decreasing content of Tb3+in the LDH.