| Al2O3 has attracted much attention as a promising matrix for Er3+ -doping lμminescent material, because it allows a relative high concentration of Er3+ and the preparation technology based on this material has been well developed. However the energy migration between Er3+ ions and -OH quenching at high Er3+ concentration limit its further application. The photolμminescent propery(PL) of rare-earth ions is closely related to its local crystal field according to the Judd-Ofelt theory. In this paper, with the aim of tailoring the local crystal field of Er3+, rare earth and non-rare earth ions with different radius were co-doped into the system to improve the distribution of Er3+ and the asymmetry and diversy of its surrounding ligand, ultimately enhance the PL property of Er3+ doped Al2O3 materials. By means of the XRD、TEM、 FTIR and PL measurement, we explored the modification of microstucture and its influencing mechanism on PL performance when different concentration of In3+/Sc3+/Ti3+ were codoped with Er, Y, Yb-Al2O3.The Er-Al2O3 powders were prepared by sol-gel method, and the effect of different sintering temperature on phase structure was investigated.δ-Al2O3 was obtained when sintered at 900℃. Er,Y-Al2O3 and Er,Y,Yb-Al2O3 powders were synthesized under the same condition. XRD and PL results indicate that the phase of Al2O3 maintains as 8 with decreased crystallinity and PL property was successively improved obviously.The ion radius of In3+(0.080 nm) and Er3+(0.089 nm) is similar, different amount of In3+ were codoped in the Er,Y,Yb-Al2O3 system. The results show that codoping with proper amount of In+ improved the distribution of Er3+ in the matrix, reduced the amount of -OH and then enhanced the PL property. When codoping with 3mol% In3+, the PL intensity at 1.53μm is the highest, which is 1.24 times higher than that non-In doped sample. When the amount of In3+ is higher than 3mol%, the amount of new phase-In2O3 increased, more and more Er3+ enter into In2O3 generated up-conversion lμminescence which deteriorate the PL performance at 1.53μm.The radius of Sc3+(0.0745 nm) is intervenient by Er3+(0.089 nm) and Al3+(0.0675 nm). Codoping with different amout of Sc3+ in Er,Y,Yb-Al2O3 system effectively improved the distribution of Er3+,Y3+,Yb3+ in the matrix, tailored the asymmetry and diversy of ligand around Er3+, and promoted the hypersensitive electron transition. The PL property remarkably enhanced with the rise amount of Er3+, especially when codoping with 10mol% Sc3+, the PL intensity is 4.7 times higher than that non-Sc sample, the corresponding full widths at the half maximμm (FWHM) and lifetime are impoved as well. The PL intensity、FWHM and lifetime could be regulated by codoping with different amount of Sc3+The radius of Ti3+ is close to Al3+, a series of Er,Y,Yb,Ti-Al2O3 powders were synthesized through the same method. The results show that the optimized codoping amount of Ti3+ is 3mol%. Right amount of Er3+ enter into the new phase-Y2Ti2O7 with an emission of 1.53μm, along with the reduced amount of -OH lead to a highest PL intensity within this group, which is 1.78 times higher than that non-Ti sample. When the amount of Ti3+exceeds 3mol%, more and more Er3+ enter into Y2Ti2O7 and caused Er3+ cluster which decreased the PL intensity. |
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