Luminance Conversion Property of Er and Yb Doped KZnF3Nanocrystal Synthesized by Hydrothermal Method

摘要

In order to make full use of exposure energy, one feasible way is to modify the luminance of crystal by rare earth doping technique. KZnF3:Er3+and KZnF3:Er3+/Yb3+nanocrystals of uniform cuboid perovskite type morphology, with average diameter of 130 nm, has been synthesized by hydrothermal method. When Yb3+ions were codoped with Er3+, absorption peak at 970 nm has been heightened and widened, and the photon absorption cross section increased. The common xenon lamp exposure cannot initiate obvious nonlinear phenomenon of the doped Er3+and Yb3+, and exposing at 245 nm only excites the fluorescence around 395 nm. Contrarily, under high power IR exposure at 980 nm, obvious upconversion photoluminescence (PL) has been observed due to the two-photon process. The PL mechanism of the doped Er3+ion in KZnF3:Er3+/Yb3+nanocrystals is confirmed. Furthermore, Yb3+codoped as sensitizer has modified the PL intensity of Er3+from green light range to red range, and the primary channel is changed from4S3/2(Er3+) →4I15/2(Er3+) of only Er3+doped KZnF3nanocrystal to4F9/2(Er3+) →4I15/2(Er3+) of Er3+/Yb3+codoped sample. With exposure energy increasing, such primary transition channel after two-photon excitation is unchanged.