Time-resolved encryption via photochromic and mechanochromic system based on silane-substituted spiropyran

With the continuous progress of forgery and decryption, the traditional static encryption technology is becoming more and more inadequate, which also strongly demands the development of multilevel anti-counterfeiting materials and advanced multi-dimensional encryption strategies and technologies. Here a new strategy to realize time-resolved encryption based on a silane-substituted spiropyran is presented, which exhibits tunable dynamic photochromic features caused by the reversible photochromic and mechanochromic properties with exceptional reversible absorption/luminescence modulation ability both in powder and crystal state. This compound shows excellent photochromic properties, including extremely rapid response time, high contrast color change, high reversibility etc. In addition, the growth of large-size needle-like single crystal by solution evaporation is helpful to further explore the mechanism of grinding discoloration of the compound. What's more, it is possible to modulate the luminescence emission and color change by simply changing the ultraviolet light stimulation time or grinding time, providing fine and adjustable time-related characteristics for the material, which can not only be used for data processing with more extended information, but also be used to construct confidential materials by time-resolved multidimensional encryption and dynamic anti-counterfeiting.