Customizing Emission Bands from Spectral Base of Lanthanide‐doped Microcrystals Enables Intelligent Information Encryption and Decryption

Abstract The unique optical properties of lanthanide‐doped microcrystals underpin their significant potential in anti‐counterfeiting and information storage domains. Traditional fluorescent anti‐counterfeiting technology is mainly dependent on the visible light emission color/pattern, facing a great risk of information leakage due to a limited spectral region and a simple operation approach. In contrast, the luminescent properties of the near‐infrared (NIR) region offer a unique advantage of invisibility to the naked eye and an extended spectral band, providing a great chance for optical multiplexing based high‐level information encryption. Herein, we designed and demonstrated a chain‐type information storage and identification platform relying on three kinds of lanthanide‐doped microcrystal labeled inks, which can flexibly mark spatially overlapped or separated regions for obtaining massive spectral and graphic information. Through precise excitation modulation and filter selection, the encrypted key hidden in blended graphics was first obtained, deciding subsequent coding rules of emission band controlled luminescent patterns. Further incorporating artificial intelligence (AI) recognition technology helped to realize efficient and accurate authentication. The combination of lanthanide‐doped microcrystals’ wide fluorescent range covering visible to NIR with intelligent authentication strategies fully demonstrates the advantage of multidisciplinary integration in anti‐counterfeiting applications, providing new insights for advancing anti‐counterfeiting technologies.