Er^3＋：Y2O3透明陶瓷制备及发光性质研究

Preparation and Photoluminescence Study of Er^(3+)∶Y_2O_3 Transparent Ceramics

以Y2O3为基质材料,掺杂不同含量的Er3+,采用共沉淀法制备出性能良好的Er3+∶Y2O3纳米粉,并将粉体在1700℃和真空度为1×10-3Pa下烧结8h得到Er3+∶Y2O3透明陶瓷。用X射线衍射仪(D/MAX-RB)、透射电子显微镜(EM420)、自动记录分光光度计(DMR-22)、荧光分析仪(F-4500)和发射波长为980nm的半导体激光器分别对样品的结构、形貌和发光性能进行了研究。结果表明:Er3+完全固溶于Y2O3的立方晶格中,Er3+∶Y2O3粉体大小均匀,近似球形,尺寸约40～60nm左右。Er3+∶Y2O3透明陶瓷相对密度为99.8%,在长波长范围内其透光率超过60%,在波长为980nm的激光下有两个上转换发光带,其中绿色发光中心波长位于562nm,红色发光中心波长位于660nm,分别对应4S3/2/2H11/2→4I15/2和4F9/2→4I15/2的跃迁;随着铒浓度的提高颜色从绿色向红色转变,Er3+的掺杂浓度不宜超过2%,超过这个范围,对材料发光强度的增强作用反而很小。

Y2O3 acted as the matrix material, which was doped with different concentrations of Er^3＋ , Er^3＋： Y2O3 nanocrystal- line powder was prepared by co-precipitation method, and Er^3＋ ： Y2O3 transparent ceramics was fabricated by vacuum sintcring at 1 700 ℃, 1 × 10^-3 Pa for 8 h. By using the X-ray diffraction （D/MAX-RB）, transmission electron microseopy（Philips EM420）, automatic logging spectrophotometer（DMR-22）, fluorescence analyzer （F-4500） and 980 nm diode laser, the structural, morphological and luminescence properties of the sample were investigated. The results show that Era dissolved completely in the Y2O3 cubic phase, the precursor was amorphous, weak diffraction peaks appeared after calcination at 400 ℃, and if calcined at 700 ℃, the precursor turned to pure cubic phase. With increasing the calcining temperature, the diffraction peaks became sharp quickly, and when the calcining temperature reached 1 100 ℃, the diffraction peaks became very sharp, indicating that the grains were very large. The particles of Er^3＋ ： Y2O3 is homogeneous and nearly spherical, the average diameter of the particles is in the range of 40-60 nm after being calcined at 1 000 ℃ for 2 h. The relative density of Er^3＋ ： Y2O3 transparent ceramics is 99.8%, the transmittance of the Er^3＋ ： Y2O3 transparent ceramics is markedly lower than the single crystal at the short wavelength, but the transmittance is improved noticeably with increasing the wavelength, and the transmittance exceeds 60% at the wavelength of 1 200 nm. Excited under the 980 nm diode laser, there are two main up-yeonversion emission bands, green emission centers at 562 nm and red emission centers at 660 nm, which correspond to ^4S3 2/^2 H11/2-^4I15/2 and ^4F12/2-^4I15/2 radiative transitions respectively. By changing the doping concentrations of Er^3＋ , the color of up-conversion luminescence can be tuned from green to red gradually. The luminescence intensity is not reinforce with the increase in the concentration, so the doping concentration of Er^3＋ should not exceed 2%. If the doping concentration of Er^3＋ exceeds the range, the concentration bas very small effect on the improvement of luminescence intensity.