title: [The upconversion luminescence characteristics of Ho3+/Yb3+ codoped ZrO2-ZnO].
abstract: Samples of Ho3+/Yb3+ codoped ZrO2-ZnO powder were prepared by a solid-state reaction. Upconversion luminescence of Ho3+ /Yb3+ codoped ZrO2-ZnO powders was reported in the present paper. The excitation spectrum detected at room temperature suggests three excitation peaks centered at 540, 671 and 762 nm respectively, corresponding to 5S2/5F4 --> I8, 5 Fs --> 5 I8, and 5S2/5 F4 --> 5 I7 or 5 I4 --> 5 I8 of Ho3+ ions. The contents of rare-earth ions could influence the property of upconversion lumunescence. When the Ho3+ content was 0.1 mol%, with the increase in Yb3+ content, the intensity of red luminescence and green luminescence decreased first and then increased, but the intensity of infrared luminescence increased first and then decreased. Furthermore, the ratio of the intensity of green emission to red emission decreased. When the Yb3+ content was 4.7 mol%, with the increase in Ho3+ content, the intensity of all emission decreased, but the ratio of the intensity of green emission to red emission was almost constant. The logI - logP curve shows that all the upconversion luminescence is double-photon processes. And the upconversion mechanisms of the samples were introduced. It is shown from the XRD spectrum that the powder of samples is uniform.
authors: Department of Electrical and Information Engineering, Hunan Institute of Engineering, Xiangtan 411101, China. firstjimu@yahoo.com.cn
authors: Xiang-Hua
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