摘要：This study presents a novel and high-level anticounterfeiting strategy based on Ce/Yb/Ho triply-doped NaGdF4 nanocrystals with temperature-responsive multicolor emission. A critical factor leading to the multicolor emission is confirmed by comparing the luminescence thermal behaviors of nanocrystals in various atmospheres. Through analyzing the temperature-dependent lifetimes of Yb 3+ ions in air, we demonstrate that thermally-induced multicolor emission mainly originates from the gradually-attenuated H2 O quenching effect. Because the cross-relaxations between Ce 3+ and Ho 3+ ions and the nonradiative transitions of Yb 3+ ions create plenty of phonon heat, the multicolor emission of nanocrystals can be achieved under 975 nm excitation at a relatively low power density. This recognition method is efficient and convenient for security authentication. The as-synthesized core nanocrystals can be directly used to fabricate anticounterfeiting ink without further processing (e.g. core/shell or hybrid). Therefore, the small-sized β-NaGdF4 :Yb/Ce/Ho nanocrystals are promising candidate for security application.
