The Electrical And Upconversion Fluorescence Propertities Of Er、Yb Co-doped PMN-PT Ceramics

Because Pb（Mg1/3Nb2/3）O3ceramics possess the excellent electrical properties.The PMN-PT ceramics is the binary system of Pb（Mg1/3Nb2/3）O3with PbTiO3,whose piezoelectric constant d33reach500pC/N and dielectric constant is20000inthe Morphotropic Phase Boundary. Besides, its electromechanical couplingcoefficient is high. Because of the good property in piezoelectric, ferroelectric anddielectric, it is the appropriate material for the high-power piezoelectric ceramictransformer.The Energy level of Er³⁺is much more than the other rare earth ions, which isevenly distributed, so it is beneficial to the upconversion photonluminescene.Besides, The Yb³⁺is the most important sensitizer to improve the efficiency ofupconversion. When Er³⁺/Yb³⁺co-doped in the material, whose light-emittingefficiency is higher than the separate Er³⁺. In addition, the upconversion iscorrelated with material. When the phonon energy is lower, the efficiency ofupcongversion is better. The PMN-PT ceramics is a goog matrix for theupconversion. Up to now, the relationship between the upconversion and the effectof poling is never reported, so it will be a major approach to the thesis.Firstly, the PMN-PT ceramics and Er³⁺/Yb³⁺co-doped PMN-PT ceramics isprepared by solid-state reaction with different sintering temperature. The samplemust be pure calcium perovskite structure and the compactness reach more than70%. Trough the Scanning Electron Microscopy, the grain size of sample isobserved. Then the ceramic is silver after polishing, we will test the ferroelectric,piezoelectric and dielectric properties. To find the best sintering temperature be1200℃, the sample, which is sintered by this temperature, is the best ceramic.Compare between the PMN-PT: Er³⁺/Yb³⁺and pure PMN-PT ceramics, it’selectrical porperty is declining with the increase of co-doped concentration. It is afocus to solve this problem in future.Nextly, we will study the Upconversion Luminescence of PMN-PT: Er³⁺/Yb³⁺ceramics. We need to solve that the Upconversion Luminescence spectrum changewith the co-doped concentration and sintering temperature. The result is theintensity is not always increasing with the increase of co-doped concentration,because there is a quenching concentration. By fitting the fluorescence of PMN-PT:Er³⁺/Yb³⁺ceramics on the pump energy, it is a two-photo luminescence process.In the thesis, the effect of poling on the piezoelectric and the intensity ofphotoluminescence in the Er³⁺/Yb³⁺co-doped PMN-PT ceramics. The cetamics is poled, whose intensity is changing but light-emitting peak has no change. So we cansee the upconversion spectra as a calibration, charactering the polarization of thematerial.