铋层状化合物Na0.5Ho0.5-xYbxBi4Ti4O15陶瓷材料的上转换发光、铁电、介电性能研究

采用传统的固相烧结法,制备了Na0.5Ho0.5-xYbxBi4Ti4O15铋层状结构陶瓷.经X射线衍射（XRD）表征,新合成材料为单相结构,且扫描电子显微镜下的表面和断面图像均为层状,说明合成材料为新型铋层状材料.室温时,在可见光波长范围内,有2个峰,分别为546 nm处的绿光峰和656 nm处的红光峰,分别对应于Ho3＋离子的5F4＋5S2→5I8和5F5→5I8跃迁.为研究其机理,测试了变功率条件下的发光强度,经计算,绿光和红光发射均为双光子过程.研究陶瓷样品在变温（-130~270°C）条件下的发光性能时,发现红光与绿光的强度比值与温度呈线性关系,该材料有望应用于光学温度传感器领域.经介电性能测试发现当Ho：Yb=1：9时,样品的居里温度为686.4°C.研究铁电性能发现当Ho：Yb=3：2时,剩余极化Pr为9.3μC/cm2,矫顽场强为Ec=82 k V/cm,表明具有一定的铁电性能.以上研究结果表明,制得的新材料是一种具有优异光学性能的多功能材料.

Up-conversion luminescent,dielectric and ferroelectric properties of new Aurivillius oxide Na0.5Ho0.5-xYbxBi4Ti4O15

Ho3＋-yb3＋co-doped Aurivillius oxide Na0.5Ho0.5-xYbxBi4Ti4O15 （NHBT） was synthesized by conventional solid-state reaction and their up-conversion luminescent, dielectric and ferroelectric properties were investigated. X-ray diffraction data showed that the samples were single phase, and SEM micrographs revealed that the ceramic samples have similar plate-like grain morphology. Under 980 nm radiation excitation, two emission bands located at 546 and 656 nm in the emission spectra were obtained at room temperature. The up-conversion emission in the ceramics was a two-photon process. The fluorescence intensity ratio of two emission bands （centered at 546, 656 nm） was studied as a function of temperature in a range of 143-543 K. The Curie temperature To of Nao.sHoo.osYbo.45BinTi4015 ceramics reached 686℃. The remanent polarization Pr and coercive electric field Ec of Na0.5Ho0.5-xYbxBi4Ti4O15 ceramics reached 9.3 gC/cm2 and Ec=82 kV/cm, respectively. All above indicated that the NHBT ceramics were a kind of multifunctional materials with excellent optical performance.