Preparation And Photoluminescence Of The Er～(3+)+Y～(3+) Doped Al₂O₃ Derived From The Non-aqueous Sol-gel Method

The 0.1 and 1 mol% Er³+ doped Al₂O₃ powders by Y³+ codoping with the molar ratio of (0-10) : 1 for Y³+ and Er³+ at the sintering temperature of 900 and 1000℃ were prepared by the non-aqueous sol-gel method. The effects of Y³+ codoping on the structure and photoluminescence properties of the powders were investigated.The 0.1 and 1 mol% Er³+-doped Al₂O₃ powders sintered at 900 and 1000 ℃ are of the mixture of γ and θ phases, which are both non-crystallization. The 0.1-1 mol% Y³+ codoping promotes the non-crystallization of the γ and θ phases for the 0.1 mol% Er³+-doped Al₂O₃ powders. The non-crystallization is also promoted by the 1-10 and 1-5 mol% Y³+ codoping for the 1 mol% Er³+-doped powders sintered at 900 and 1000 ℃ respectively, while the γ phases disappeares and the (Er,Y)₃Al₅O₁2 compound appears for the 1 mol% Er³+-doped powders at the sintering temperature of 1000 ℃ by 10 mol% Y³+ codoping. The FTIR spectra shows that the wavenumber range and the intensity of the absorption peak for O-H have no evident changes for the powders by Y³+ codoping sintered at same temperature, indicating that Y³+ codoping has no influence on the oscillation frequency and content of the O-H for the Er³+-doped Al₂O₃ powders.The Er³+-doped Al₂O₃ powders are characteristic of the photoluminescence (PL) spectra peaked at 1.53 urn, 660 nm (red emission), 545 and 523 nm (green emission) pumping by the laser with wavelength of 980 nm, and the emission peaked at 1.53μm is of stokes emission while the other two are of up-conversion emission. Y³+ codoping has evident effects on the PL properties of the powers. On the one hand, Y³+ codoping decreases the phone energy of the powders and increases the lifetime of the ⁴I₁1/2 level for Er³+, leading to a decrease in the intensity of Stokes emission and red emission as well as a increase in the intensity of green emssion and a decrease in the intensity ratio for the red emission and green emission. On the other hand, Y³+ codoping effectively decreases the concentration quenching effect of the Er³+, leading to an increase in the intensity of both Stokes emission and upconversion emission. For the 0.1 mol% Er³+-doped Al₂O₃ powders, the concentration quenching has small effect on its PL, and the Y³+ codoping only decreases its phone energy with a corresponding changes in its PL intensity. For the 1 mol% Er³+-doped powders, Y³+ codoping decreases both the phone energy and the Er³+ concentration quenching, leading to an increase in both the Stokesemission and the upconversion emission with a decrease in the intensity ratio for green emssion and red emission. Y3+ codoping also influence the full width at half maximum (FWHM) of the PL spectrum peaked at 1.53 um for the Er3+-doped AI2O3 powders. For the 0.1 mol% Er3+-doped powders sintered at 900 °C, the FWHM of the PL spectra has no evident change with Y3+ codoping, for that sintered at 1000 °C, the FWHM increases slightly by Y3+ codoping. The FWHM of the PL spectra for the 1 mol% Er3+-doped AI2O3 powders sintered at 900 and 1000 °C both increase with the increase of the Y3+ codoping concentration, except a decrease in the FWHM of the spectrum for the powders sintered at 1000 °C by 10 mol%Y3+codoping.