Multi-mode excited Cs2NaBiCl6 Based Double Perovskite Phosphor for Anti-counterfeiting

Abstract

Emission wavelength or color and excitation mode of luminescent materials play the decisive role in their applications of information hiding and anti-counterfeiting. Conventional luminescent anti-counterfeiting materials generally exhibit monochromatic emissions under the excitation of ultraviolet or near-infrared light, which are easily to be imitated or substituted. The development of multicolor and multimodal excitation in one single-phased host was regarded as effective strategy and significant challenges for luminescent anti-counterfeiting materials. As typical lead-free halide double perovskite material Cs2NaBiCl6 not only offers excellent stability and facile synthesis but also provides greater tolerance to rare earth and transitional ions, thus Er3+, Yb3+ and Mn2+ tri-doped Cs2NaBiCl6 was synthesized by co-precipitation method at room temperature in this paper. The efficient green up- and strong orange red down-conversion (UC and DC) emissions were realized through irradiation of 980/1550 nm infrared light and 365 nm near ultraviolet light. The possible UC mechanisms and energy transfer from Er3+ to Mn2+ were also investigated, and some fluorescent security patterns were also designed to demonstrate the potential applications of the present samples in anti-counterfeiting and concealing important information.