Smart inks based on AIPE-active heteroleptic Ir(III) complexes

In the present work, two environmentally friendly inks were obtained, capable of achieving information encryption based on two Ir(III) complexes with both multi-stimuli-sensitive and aggregation-induced phosphorescent emission (AIPE) properties. Two inks were prepared from the Ir(III) complexes, respectively. Interestingly, the two inks were coated on glass films and heated; a change in color was then observed under ultraviolet (UV) excitation. The color-changing temperatures of the films were 220 and 180 °C, meaning that temperature could be utilized as the “key” or “lock” to confidential information. More specifically, the encrypted information could be decrypted only by heating the glass film to the correct temperature; excessive heating caused the permanent damage and hiding of the information. All results indicated that the inks were promising solutions for information encryption.