Fluorescence and phosphorescence dual-light-emitting 3D cubes for high-security optical encryption. Credit: Jin Woo Oh, Seokyeong Lee, Hyowon Han, Omar Allam, Ji Il Choi, Hyeokjung Lee, Wei Jiang, Jihye Jang, Gwanho Kim, Seungsoo Mun, Kyuho Lee, Yeonji Kim, Jong Woong Park, Seonju Lee, Seung Soon Jang, and Cheolmin Park
They presented fluorescent perovskite nanocrystals embedded in metal–organic frameworks designed for phosphorescent host–guest interactions. When guest molecules for room temperature phosphorescence were securely fixed within each periodic cavity of a molecular framework, the host–guest pairs were rigidified with fixed molecular separation, owing to the crystalline structure of the MOFs, resulting in stable room temperature phosphorescence without additional processes.
This method and technique will open new avenues for developing room-temperature multi-light-emitting materials and a strategy for multidimensional information encryption with enhanced capacity and security. Summarizing their research, the scientists say,"We design a fluorescent-phosphorescent dual-light-emitting materials for optical information encryption. Utilizing dual-light-emitting materials that exhibit distinct and individual fluorescence and phosphorescence emissions, 2-D pochoir pattern encryption effectively conceals real information through transient phosphorescence, while fake information is presented through fluorescence.