摘要
Three types of β-NaYF_4nanoparticles, uncoated core（NaYF_4：Yb/Ho/Ce）, single-layer coated core@shell（NaYF_4：Yb/Ho/Ce@NaYF_4：Yb） and double-layer coated core@shell@shell（NaYF_4：Yb/Ho@NaYF_4：Yb@NaYF_4：Yb） with Ce^（3＋） doped in core, first and second shell, respectively, were synthesized through solvothermal method to investigate the cross-relaxation between Ho^（3＋） and Ce^（3＋） for the tunable upconversion luminescence. By doping Ce^（3＋） into different layers with different doping concentrations, a systematical investigation on the tunable upconversion luminescence from green to red was conducted. The results showed that a remarkable color tuning could be achieved from green to red when increasing the doping concentration of Ce^（3＋） in the same layer of Ho^（3＋）. And if Ce^（3＋） and Ho^（3＋） were separated in different layers, the color tuning would be depressed significantly due to the reduced cross-relaxation between Ho^（3＋） and Ce^（3＋）. Moreover, the UC emission intensity of core@shell and core@shell@shell was enhanced significantly compared with that of unmodified core nanoparticles.
Three types of β-NaYF_4nanoparticles, uncoated core（NaYF_4：Yb/Ho/Ce）, single-layer coated core@shell（NaYF_4：Yb/Ho/Ce@NaYF_4：Yb） and double-layer coated core@shell@shell（NaYF_4：Yb/Ho@NaYF_4：Yb@NaYF_4：Yb） with Ce^（3＋） doped in core, first and second shell, respectively, were synthesized through solvothermal method to investigate the cross-relaxation between Ho^（3＋） and Ce^（3＋） for the tunable upconversion luminescence. By doping Ce^（3＋） into different layers with different doping concentrations, a systematical investigation on the tunable upconversion luminescence from green to red was conducted. The results showed that a remarkable color tuning could be achieved from green to red when increasing the doping concentration of Ce^（3＋） in the same layer of Ho^（3＋）. And if Ce^（3＋） and Ho^（3＋） were separated in different layers, the color tuning would be depressed significantly due to the reduced cross-relaxation between Ho^（3＋） and Ce^（3＋）. Moreover, the UC emission intensity of core@shell and core@shell@shell was enhanced significantly compared with that of unmodified core nanoparticles.
基金
Project supported by the National Key Basic Research Program of China(2013CB921800)
the National Natural Science Foundation of China(11374291,11204292,11274299,11311120047)
the Fundamental Research Funds for the Central Universities(WK2030020021)
