%A Thi Dung Nguyen
%A Van Thanh Hoang
%A Dinh Lam Nguyen
%J Influences of growth durations on characteristics of NaYF4:(Yb,Tm) upconversion materials
%T Influences of growth durations on characteristics of NaYF4:(Yb,Tm) upconversion materials
%X NaYF4:(Yb,Tm) upconversion materials  were synthesized by the simple hydrothermal method. Growth duration was varied from 4h to 12h under a growth temperature of 150oC. The structural, optical and surface morphology characteristics of the NaYF4:(Yb,Tm) UC materials were investigated. The XRD and SEM results illustrated that the NaYF4:(Yb,Tm) materials were transformed from the multiple phases (hexagonal and cubic) to the single-phase (hexagonal prism) as growth duration being longer than 8h with the average diameter and length of these prisms being about 0.5 µm and 2 µm, respectively. Under 980 nm laser excitation, the NaYF4:(Yb,Tm) emits at peaks of 450 nm (1D2→ 3F4), 475 nm (1G4→3H6), 647 nm (1G4→3F4) and 697  nm (3F3→3H6), with the highest emission belonging to NaYF4:(Yb,Tm) grown for 8h.
%N 4
%V 35
%D 2019
%I VNU Journal of Science: Natural Science and Technology
%L SisLab3809