RESUMEN
Abstract In the present paper, we reported the luminescence properties of BiOCl:Dy(3+) and BiOCl:Dy(3+), Li+ phosphor synthesized by conventional solid state method. X-ray diffraction (XRD) and excitation and emission spectroscopy were used to characterize the samples. Results show that pure tetragonal BiOCl:Dy(3+) crystals can be synthesized successfully at 500 °C, and Li+ ion dopant improves the crystallinity of samples furtherly. Under near UV light excitation, the samples,give the characteristic luminescence of Dy(3+) ions located at 478 (blue) and 574 nm (yellow), which show a low yellow-to-blue intensity ratio (Y/B) of Dy(3+) emission and white light emission. Moreover, codoping of Li+ ion can realize the enhancement of emission intensity and the adjustment of emission color. The characteristics of BiOCl:Dy(3+) phosphor, low temperature preparation, good near ultraviolet excitation and white light emission make it to a promising near-ultraviolet WLED phosphor.
RESUMEN
The Sb2O4:Yb3+, Tm3+ up-conversion luminescence powder with excellent physical, chemical stability and relative low phonon energy was synthesized by the high temperature solid-state reaction and its up-conversion luminescence property was investigated. Under the 980 nm excitation, infrared and blue up-conversion emissions centered at 800 and 480 nm were observed, which were assigned to the 1G4-->3H6 and 3H4-->3 He transitions of Tm2+, respectively. The influence of Yb3+ and Tm3+ concentration on the up-conversion emission property was also obtained. The up-conversion luminescence increases with increasing of Yb3+ and Tm3+ concentration. Additionally, the up-conversion luminescence mechanism was discussed based on the dependence of Tm3+ up-conversion luminescence on pump power. It is interesting that two photon excitation processes for blue and infrared emission were observed in the Sb2O04: Yb3+, Tm3+ powder under a 980 nm excitation. Based on the energy level diagram of Tma3 and Yb2+ ions, we think that two photons blue emission is contributed to the cooperation energy transfer between Tm"+ and Yb3+ ions. We believe that the Sbz04 : Yb3 , Tm2+ up-conversion luminescence powder will have potential application for new optical devices in up-conversion color displays, sensors, detection of infrared radiation, and lasers.
RESUMEN
The BaZrO3 : 0.05Bi, xEu(x = 0, 0.010, 0.025, 0.050) phosphors were prepared by using high-temperature solid-state reaction in reducing atmosphere, and their photoluminescence properties were investigated. The broadband emission peak of Bi3+ and the typical emission peaks of Eu3+ were observed in the BaZrO3 phosphors co-doped with Bi3+ and Eu3+ under 340 nm excitation. It is confirmed that energy transfer occurred between Bi3+ and Eu3+ in the BaZrO3 : Bi, Eu phosphors, and the white light BaZrO3 phosphors can be obtained through the energy transfer between Bi3+ and Eu3+.
RESUMEN
OBJECTIVE: To evaluate the cytocompatibility of nanophase hydroxyapatite ceramics in vitro. METHODS: Hydroxyapatite (HA) was prepared via wet method. The grain size of the hydroxyapatite in the study was determined by scanning electron microscope and atomic force microscope with image analysis software. Primary osteoblast culture was established from rat calvaria. Cell adherence and proliferation on nanophase hydroxyapatite ceramics and conventional hydroxyapatite ceramics were examined at 1, 3, 5, 7 days. Morphology of the cells was observed by microscope. RESULTS: The average grain size of the nanophase and conventional HA was 55 nm and 780 nm, respectively. Throughout 7 days period, osteoblast proliferation on the HA was similar to that on tissue culture borosilicate glass controls, osteoblasts could attach, spread and proliferate on HA. However, compared to conventional ceramics, osteoblast proliferation on nanophase HA was significantly better after 1, 3, 5 and 7 days. CONCLUSION: Cytocompatibility of nanophase HA was significantly better than conventional ceramics.