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Whispering‐gallery‐mode (WGM) microcavities featuring distinguishable sharp peaks in a broadband exhibit enormous advantages in the field of miniaturized photonic barcodes. However, such kind of barcodes developed hitherto are primarily based on microcavities wherein multiple gain medias were blended into a single matrix, thus resulting in the limited and indistinguishable coding elements. Here, a surface tension assisted heterogeneous assembly strategy is proposed to construct the spatially resolved WGM hetero‐microrings with multiple spatial colors along its circular direction. Through precisely regulating the charge‐transfer (CT) strength, full‐color microrings covering the entire visible range were effectively acquired, which exhibit a series of sharp and recognizable peaks and allow for the effective construction of high‐quality photonic barcodes. Notably, the spatially resolved WGM hetero‐microrings with multiple coding elements were finally acquired through heterogeneous nucleation and growth controlled by the directional diffusion between the hetero‐emulsion droplets, thus remarkably promoting the security strength and coding capacity of the barcodes. The results would be useful to fabricate new types of organic hierarchical hybrid WGM heterostructures for optical information recording and security labels. [ABSTRACT FROM AUTHOR]

Metal‐organic frameworks (MOFs) heterostructures with domain‐controlled emissive colors have shown great potential for achieving high‐throughput sensing, anti‐counterfeit and information security. Here, a strategy based on steric‐hindrance effect is proposed to construct lateral lanthanide‐MOFs (Ln‐MOFs) epitaxial heterostructures, where the channel‐directed guest molecules are introduced to rebalance in‐plane and out‐of‐plane growth rates of the Ln‐MOFs microrods and eventually generate lateral MOF epitaxial heterostructures with controllable aspect ratios. A library of lateral Ln‐MOFs heterostructures are acquired through a stepwise epitaxial growth procedure, from which rational modulation of each domain with specific lanthanide doping species allows for definition of photonic barcodes in a two‐dimensional (2D) domain with remarkably enlarged encoding capacity. The results provide molecular‐level insight into the use of modulators in governing crystallite morphology for spatially assembling multifunctional heterostructures. [ABSTRACT FROM AUTHOR]

Keywords: 2D photonic barcodes; anti-counterfeiting applications; dimensional modulation; lanthanides; MOF heterostructures EN 2D photonic barcodes anti-counterfeiting applications dimensional modulation lanthanides MOF heterostructures 24931 24931 1 11/02/21 20211108 NES 211108 B Mehrfarbige Heterostrukturen b auf der Basis von Lanthanoid-basierten metallorganischen Gerüsten (Ln-MOFs) haben großes Potenzial für fälschungssichere Anwendungen gezeigt. Innenrücktitelbild: Laterally Engineering Lanthanide-MOFs Epitaxial Heterostructures for Spatially Resolved Planar 2D Photonic Barcoding (Angew. In ihrem Forschungsartikel auf S. 24724 präsentieren Zhenhua Gao, Xiangeng Meng, Yong Sheng Zhao et al. eine Strategie, um laterale 2D-Ln-MOFs zu konstruieren. [Extracted from the article]