RESUMO
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.
RESUMO
Samples of Er+3/Yb3+ codoped 3CaO-Al2O3-3SiO2 compounds were prepared, and the properties of frequency upconversion of the samples under the excitation of 980 nm diode laser were studied. Green and red emissions centered at 523, 547 and 656 nm, corresponding to the transitions 2H(11/2)-->4I(15/2), 4S(3/2)-->4I(15/2), and 4F(9/2)-->4I(15/2), respectively, were observed. The dependence of the upconversion fluorescence intensity on the pumping power, and the phonon energy of each sample were observed, and the mechanism of frequency upconversion based on these two items was discussed.
