Construction of a novel pitaya-like CsxWO3@NaYF4:Yb, Er particles with simultaneous colour tuning and upconversion luminescence enhancement

In order to further improve the luminescence of NaYF 4 :Yb,Er, we successfully constructed pitaya-like Cs 0 · 3 WO 3 @NaYF 4 :Yb, Er particles, in which Cs 0 · 3 WO 3 particles were encapsulated in NaYF 4 :Yb, Er particles. This structure enhanced the intensity of 407, 527, 542 and 657 nm emission peaks by 10.1, 5.9, 5.5 and 1.8 times, respectively. Through calculated, the Commission Internationale de l’Eclairage (CIE) chromaticity coordinates changed from (0.28, 0.71) to (0.25, 0.73), indicating that the emission colour was tuned from yellow to green. The construction mechanism of this structure and the mechanism of upconversion (UC) luminescence enhancement were discussed. By studying the different luminescence mechanisms of NaYF 4 :Yb, Er excited by 1550 and 980 nm laser, we found that the UC luminescence enhancement and colour tuning of NaYF 4 :Yb, Er were due to the localized surface plasmon resonance (LSPR) effect of Cs 0 · 3 WO 3 , which can absorb more excited photons and transfer them to the Er 3+ ion 4 I 11/2 level. Given that the transition process of green light emission is easier than red light emission, the redundant photons are more inclined to achieve emitting green light and show UC luminescence enhancement and emission colour tuning. Overall, the as-prepared novel pitaya-like Cs 0 · 3 WO 3 @NaYF 4 :Yb, Er particles exhibit strong UC luminescence enhancement and colour tuning, thus having great application prospect in the field of luminescent displays.