Study Of Two/Three-Photon Upconversion On Fluorides Nanometer Materials

In the rare-earth up-conversion luminescence study, how to effectively improve the rare earth ion upconversion luminescence efficiency has always been an important issue . The nanoupconverion luminescence materials NaYF₄:Er³⁺,NaYF₄:Er³⁺,Yb³⁺ and NaYF4:Er³⁺,Yb³⁺,Tm³⁺ were prepared from the quaternary microemulsions of CTAB. n-butanol, n-octane and water by hydrothermal microemulsions method. The X-ray diffraction (XRD) patterns were indexed to pure prepared sample phases showed that it is the phase of cubic symmetry and the diameter of the particales, calculated with the help of Debye-Scherrer equation, revealed that these particales were nanoparticals.The near infrared emission band of nanoparticles peak of NaYF₄ :Er³⁺at about 1540 nm (⁴I_13/2→⁴I_15/2), That NaYF₄ :Er³⁺/Yb³⁺ at about 975nm (²F_7/2→²F_5/2) and 1540nm.NaYF₄:Yb³⁺/Er³⁺/Tm³⁺at about 975nm,1209nm(³H₆→³H₅), 1540nm and 1668nm (³H₆→³F₄) excited by using 514nm laser. By using 980nm laser to excited The sample NaYF₄:Er³⁺/Yb³⁺.NaYF₄:Yb³⁺/Er³⁺/Tm³⁺, red ,green and blue light can be observed respectively .By studying the relationship between the pump power and the luminous intensity, identified that both red emission and green emission are the absorption process of double-photon and blue emission is the absorption of three-photon .In preparing NaYF₄:Yb³⁺/Er³⁺/Tm³⁺,the influences that rations Yb³⁺ions and Er³⁺ ions to Er³⁺ ions .hyrothermal temperature and reaction time and other facts on the upconversion luminescent nature and luminescent intensity were discussed. The influence of nature and intensity of luminescence and up-conversion light-emitting energy in the process of transition and the energy transfer process were also discussed.