ZnO:Er3+纳米晶的制备及发光性质研究

为了探讨稀土Er3 与纳米ZnO基质之间的能量传递,利用化学方法制备了ZnO:Er3 纳米晶,测量了样品的X射线衍射谱(XRD)、光致发光谱(PL)和激发谱(PLE).X射线衍射结果表明,ZnO:Er3 具有六角纤锌矿晶体结构.室温下,在365 nm激发下,在ZnO宽的可见发射背景上,观测到了Er3 的激发态4S3/2(550 nm),2H11/2(521 nm)和4F5/2(456 nn)的特征发射.分析了ZnO:Er3 纳米晶的带边发射和稀土Er3 的特征发射的峰值强度随掺Er3 浓度的变化关系,比较了ZnO:Er3 与未掺杂的ZnO的光致发射峰值强度的变化,给出了稀土Er3 的激发态4S3/2→4I15/2,2H11/2→4I15/2和4F5/2→4I15/2的发射机制,证实了纳米ZnO基质与稀土Er3 离子之间存在能量传递.

Preparation and Photoluminescence Investigation of Erbium-Doped Zinc Oxide Nanocrystalline

Er3+ -doped zinc oxide nanocrystalline powders were successfully prepared by chemical precipitation method. Photoluminescence spectrum (PL), photoluminescence spectrum excitation(PLE) and X-ray diffraction pattern (XRD) of the nanocrystalline ZnO:Er3+ with excitation wavelength 365 nm were measured at room temperature. XRD pattern indicates nanocrystalline ZnO:Er3+ has a hexagonal wurtzite structure and polycrystallining. The mean grain size of nanocrystalline ZnO:Er3+ was calculated with Debye-Scherrer formula. The luminescence process of Er3+ -doped zinc oxide nanocrystalline was investigated by using PL and PLE. Emissions of S(3/2)(550 nm), 2H(11/2))(521 nm) and 4F(5/2)(456 nm) of Er3+ ions were observed in wide visible band of ZnO. By analyzing the spectrum the effect of Er3+ -doping on the luminescence of ZnO was studied. An energy transfer from excited states of ZnO hosts to doping Er3+ ions centers was disclosed by the fact that photoluminescence intensity maximum of nanocrystalline ZnO = Er3+ changed with the doping concentration of Er3+.