Structural Features and Color Tunable Photoluminescence of The Binary and Ternary Layered Rare-Earth Hydroxides of (Y, Ln)2 (OH)sNO3·nH2O(Ln=Tb, Eu)

摘要

A series of layered rare-earth hydroxides (LRHs) of(Y,Ln)2(OH)5NO3·nH2O (Ln=Tb,Eu),have been synthesized via a hydrothermal route.Crystal structures and optical properties of the materials have been investigated in detail by the combined techniques of XRD,FT-IR,FE-SEM,HR-TEM,and PLE/PL spectroscopies.It is shown that Tb3+ and Eu3+ are successfully incorporated into the Y-LRH host lattice to form solid solutions.Under UV excitation,the binary (Y0.97Tb0.03)-and (Y0.97Eu0.03)-LRHs exhibit their respective characteristic photoluminescence of the EU3+ and Tb3+activators.The ternary (Y0.965Eu0.005Tb0.03)-LRH simultaneously shows red and green emissions and both the intensity and emission color can be adjusted by changing the excitation wavelength.Compared with (Y0.995Eu0.005)-LRH,the ternary (Y0.965Eu0.005Tb0.03)-LRH exhibits appreciably enhanced 615nm red-emission,which indicates the existence of non-radiative energy transfer from Tb3+ to Eu3+.The ternary (Y0.965Eu0.005Tb0.03)-LRH also readily undergoes anion exchange with a series of inorganic and organic anions at room temperature.