Upconversion luminescence is characterized by the conversion of near-infrared excitation into ultraviolet and visible emissions through a special class of doped optical materials. Recent advances in chemical synthesis have enabled the precise incorporation of multiple dopant ions into a single substrate of well-controlled size and morphology, which render emissions with distinguishable spectroscopic fingerprints as well as spatially and temporally resolved features. These luminescence characteristics hold great promise in anti-counterfeiting applications by encoding high-capacity optical codes. In this review, we focus on recent advances in anti-counterfeiting technology that exploits the remarkable tunability of upconversion luminescence to design optical codes with high-level security. We discuss various approaches for the design of upconversion materials and construction of upconversion codes, along with an analysis of future challenges for upconversion-based anti-counterfeiting.

上转换发光的特点是通过一类特殊的掺杂光学材料将近红外激发转换为紫外和可见光发射。化学合成的最新进展已经能够将多种掺杂离子精确地结合到尺寸和形态可控的单个基板中，这使得发射具有可区分的光谱指纹以及空间和时间分辨的特征。通过编码高容量光代码，这些发光特性在防伪应用中具有广阔的前景。在这篇综述中，我们关注防伪技术的最新进展，该技术利用上转换发光的显着可调性来设计具有高级别安全性的光代码。