Metal-to-insulator phase transition of molybdenum oxide for reversible writing and erasing information encryption

Abstract Recent research on structural color manipulation is focusing on integrating phase change material (PCM) in plasmonic structures. Commonly reported PCM integrated plasmonic structures can only achieve information manipulation by switching images between different colors. In this paper, we have reported a theoretical design of reversibly switching colored information between visible and invisible simply using a MoO x based two layered structure. In our design, the MoO x layer can be switched between two phases, i.e., metallic MoO 2 and insulating MoO 3 . The phase transition of MoO x possesses very complicated processes, which makes it advantageous for information encryption. Generally, in the proposed structure with metallic MoO 2 , various colors can be generated due to the F-P enhanced absorption at wavelengths where construction interference occurs. However, owing to the low loss of insulating MoO 3 in visible region, the absorption is low though out the whole visible region. Thus all colors can be erased to white. Therefore, the colored information can be written and erased with our proposed structure by switching MoO x between metallic MoO 2 and insulating MoO 3 . Utilizing the designed structure, we presented two kinds of devices possessing the functions of image ‘writing and erasing’ to verify the possibility of application in information encryption. The proposed image encryption device can be acquired easily by masking and coating processes. We believe our results provides a new way in designing encryption devices.