Dual upconversion nanophotoswitch for security encoding

用于安全编码的双模式上转换纳米光开关（英文）

Light-harvesting lanthanide ions(Ln3+) doped NaYF4 inks could provide polychromatic patterns for opposing counterfeiting commodity infestation because of their distinctive upconversion photoluminescence(UPL) properties. Herein, three kinds of core-triple-shell Ln3+ions doped NaYF4 upconversion nanocrystals(UCNCs) are synthesized through modified high-temperature coprecipitation, which demonstrate excellent UPL properties of independent emitting colors under 808 or 980 nm laser excitation. Additive mixing three kinds of 808 nm emitted red-green-blue(RGB)UCNCs colloid solution can precisely regulate the emissions of the suspension for achieving full-color display. The as-obtained RGB three-primary colors induced by 808 nm laser accomplish broader color gamut than traditional standard RGB(s RGB) model and printing cyan-magenta-yellow(CMY)model. In addition, various China zodiac patterns and complex multicolor images are printed by the as-formulated UCNCs inks through screen printing technology. The printed patterns present colorful and polychromatic sequential toning visualization patterns under 808 nm excitation, while present another succession of gradually changed versatile patterns under 980 nm excitation. As a proof of concept, transparent polyvinyl chloride(PVC) self-adhesive anti-counterfeiting label is attached to the bottle of wine package for practical application. The demonstration of multiple model patterns of Chinese zodiac and poetry images based on these core-tripleshell UCNCs can be selected as a conceivable substitute of traditional single model patterns, underlining the full-color anti-counterfeiting level.

镧系离子掺杂的NaYF_4油墨由于其独特的上转换光致发光特性可以被应用到防伪领域.本文首先通过高温共沉淀法合成了三种核-壳结构的镧系离子掺杂的NaYF_4上转换纳米材料,它们在808和980 nm激光激发下均可以表现出差异性的上转换荧光性能.其次,通过物理混合808 nm激发的不同颜色的悬溶液红绿蓝,可以调节混合液的发光颜色,实现全彩色显示. 808 nm激发产生的颜色可以实现比sRGB和印刷CMY颜色空间模型更宽的色域.最后,我们使用传统丝网印刷技术印刷出中国十二生肖图案和其他大面积的复杂图像,印刷图案在808 nm激发下可以呈现出一组多色连续的图案,同时在980 nm激发下也可呈现出另一组逐渐改变的多色图案,而且,印刷在透明聚氯乙烯PVC标签的图案可以附在酒瓶包装上,实现酒瓶包装的防伪.基于NaYF_4的双模式荧光图案可以替代传统单模式荧光图案,实现高水平的全色防伪及安全编码.