Synthesis And Up-Conversion Luminescence Of Fluoride Codropped With Rare Earth/Transition Metal

More and more attentions have been paid to rare earth up-conversion materials due to their potential applications in the fields of biological labels, three-dimensional flat-panel display devices, fluorescent falsification-preventing, solar cell and upconversion fiber lasers.Among the various UC materials, fluorides are excellent host materials because of their low phonon energy and high chemical stability.Under this background, this dissertation is taking NH4F as the source of fluorine,using solvothermal method to prepare the MnF2:Er3+, Yb3+?BaLnFs:Yb3+, RE3+(Ln=Y, Ce, Gd, Lu; RE=Er3+, Ho3+, Tm3+) up-conversion materials,BaLnF5:Yb3+, Ho3+/Tm3+(Ln=Ce? Gd?Lu) nanocrystals doped with different Mn2+contents were prepared and discusses the influence of concentration of Mn2+ions up-conversion luminescence.The main contents and results are described as follows:With the solvothermal method, n(RE3+):n(F-)=1:10,5%PEI ethylene glycol solution are used as solvent, can prepare pure phase, uniform particle size, good luminous performance MnF2:Er3+, Yb3+nanocrystals with truncated octahedron.Under 980 nm laser excitation, the samples have three emission peaks at 525 nm,539nm and 650 nm, the red emission at 650 nm is the strongest.Using 5% PEI ethylene glycol solution as solvent,fill factor is 50%, n (Yb3+):n (Er3+)=9:1, response for 14 hours under 200?, can get high luminous efficiency, pure phase BaYF5:Yb3+, Er3+nanocrystals with spherize, witch belongs to tetragonal crystal system.The synthesis conditions were applied to the synthesis of other rare earth fluoride BaLnFs:Yb3+, Er3+, and the products were pure phase eitherBaLnFs:Yb3+, RE3+(Ln=Ce, Gd, Lu; RE=Er3+, Ho3+, Tm3+) were prepared, The particle size of the sample increases with the increase of the atomic number of Ln3+ in BaLnF5.There are three kinds of materials that have the highest luminescence intensity, they are BaCeFs:Yb3+, Er3+; BaGdFs:Yb3+, Tm3+and BaLuFs:Yb3+, Ho3+.BaCeF5:Yb3+, Er3+can emit red light, BaGdF5:Yb3+, Tm3+can emit blue light and BaLuFs:Yb3+, Ho3+emit green light under the 980 nm laser excitation.The doping of Mn2+ions can cause the change of the luminescence intensity of the nanoparticles.In Ba1-xLnFs:Yb3+, Ho3+, Mn2+x (Ln=Ce?Gd?Lu) nano materials, Mn2+ ions can inhibit green emission and enhance the red emission intensity, when the doping amount of Mn2+ions is x= 0.3, the three material of red light intensity reached the highest value.In BaCeF5:Yb3+, Tm3+and BaLuFs:Yb3+, Tm3+nanocrystals, when Mn2+ions doped amount of x=0.3, near infrared luminescence intensity of 800nm is the strongest, and in BaGdFs:Yb3+, Tm3+, Mn2+ions doped amount of x=0.6, near infrared luminescence intensity is the strongest.