Co-doped perovskite nanocrystals for multiplexed anticounterfeiting applications

Transition and lanthanide metal ion doping in colloidal perovskite nanocrystals results in efficient visible to near-infrared emission. Here, we explore the role of visible and near-infrared multi-emission pathways provided through Mn-doped and Yb-Mn co-doped perovskite nanocrystals within advanced photoluminescence-based security features. The features provide overt functionality through visible photoluminescence from the underlying Mn-dopants. Meanwhile, the Yb-dopants enable covert information to be concealed through their inherent near-infrared emission. These engineered printed patterns are assessed in terms of ambient, moisture, and thermal stability. Finally, the complexity of encryption is further enhanced by chemically engineering the host-dopant energy transfer processes through anion exchange reactions. This enables write and erase functions to be realised in these perovskite NC-based security features.