摘要
The white upconversion luminescence （UCL） of upconversion nanoparticles （UCNPs） is mainly made up of the color red, green and blue. Interestingly, the white-light-emitting UCNPs can be obtained via a complex method of tridoping lanthanide ions such as Yb^3＋, Er^3＋, and Tm^3＋. We herein report that an excellent white UCL can be obtained from Yb/Tm double-doped ZnO. In this system, the blue and red UCL-emissions around 475 and 652 nm originate from ^1G4→^3H6 and ^1G4→^3F4 transition of Tm^3＋, respectively, and the green one can be attributed to the defect states （oxygen va- cancies） luminescence （DSL） of the ZnO host. Meanwhile, the fine nanostructure of ZnO：Yb/Tm is prepared by adjusting the concentration of OH-. Particularly, the one dimentional pencil-shaped nanorods with high aspect ratio achieve a strong green DSL emission due to the high concentration of oxygen vacancy. The oxygen vacancy defects play an irreplaceable role in affecting the intensities of blue and red UCL by acting as the intermediate state in the energy transfer process. More importantly, we demonstrate that the DSL and UCL can be combined into systems, paving a new road for obtaining the white UCL emission.
上转换白光由红色、绿色和蓝色组成,而上转换白光通常是通过复杂的三掺杂稀土离子如Yb^(3+)、Er^(3+)和Tm^(3+)实现的.本文报道了一个新型村料,通过Yb^(3+)、Tm^(3+)双掺ZnO实现上转换白光输出.体系获得475 nm(~1G_4→~3H_6)上转换蓝光和652 nm(~1G_4→~3F_4)上转换红光,上转换绿光发射源于ZnO基质村料缺陷(氧空位)发光.此外,通过调节OH-的浓度可以调控纳米村料形貌.尤其是铅笔状结构纳米棒由于表面具有高浓度的氧空位,实现了上转换绿光辐射.同时氧空位缺陷作为能量传递过程的中间态能级,提高了上转换蓝光以及上转换红光的发光强度.我们的研究首次将缺陷发光机理和上转换发光机理相结合,为实现上转换白光输出开辟了新道路.
基金
supported by the National Natural Science Foundation of China (11374080)
