采用共沉淀法制备了四方相锆石型结构 YVO4∶ Yb3+,Er3+纳米粒子。粒子表面光滑,结晶良好,呈类球状,粒径~80 nm。在980 nm 和1550 nm 红外激发下,粒子呈现类似的特征发射,峰位位于634~706 nm 的红光和513~573 nm 的绿色分别归因于 Er3+离子4 F9／2→4 I15／2和2 H11／2,4 S3／2→4 I15／2能级间的辐射跃迁。通过激发光波长控制,在同组分粒子中实现了颜色可控的高色纯度绿、红色发光,对应的绿红光和红绿光分支比分别高达29.5和37.97。借助能级跃迁模型,详细讨论了不同激发条件下的纳米粒子上转换发光的跃迁和变化机制。%Near-spherical and well crystallized YVO4∶ Yb3 + ,Er3 + nanoparticles with tetragonal zir-con structure were prepared by co-precipitation method. The average particle size is 80 nm. Under 1 550 and 980 nm excitation, the observed emissions of the particles are similar and locate near 513 -573 nm and 634 - 706 nm corresponding to 2 H11 / 2 / 4 S3 / 2 → 4 I15 / 2 and 4 F9 / 2 → 4 I15 / 2 transitions of Er3 +ions,respectively. By controlling the excitation wavelength, color-tunable and high-purity green and red up-conversion luminescence( UCL) from the same component nanoparticles can be obtained. Under the excitation of 980 nm, the intensity ratio value of green and red emission reaches 29. 5. However, when the excitation source is replaced by 1 550 nm diode laser, a bright red emission with high color purity is observed. Here, the maximum value of the intensity ratio of red and green emis-sion is 37. 97. Furthermore, the different UCL transition mechanisms of the phosphor excited by 980 nm and 1 550 nm are discussed in detail by means of Er3 + energy model.
展开▼
