Rewritable optical data storage based on mechanochromic fluorescence materials with aggregation-induced emission

In this work, the synthesis and aggregation-induced emission (AIE) properties of a new molecular system are reported. This system composes of three positional isomers, which are fabricated by attaching a methoxy group in different locations. The isomeric effects on the AIE properties as well as the intramolecular charge transfer (ICT) processes were studied. Additionally the new isomers exhibit mechanochromic fluorescence (MCF). Among the three isomers, (E)-2-(((6-chlorobenzo[d]thiazol-2-yl)imino)methyl)-5-methoxyphenol (CHM3) exhibits the most remarkable MCF performance with emission that decreases in intensity and red-shifts in wavelength under mechanical stimuli. The emission changes are caused by crystalline-amorphous transition as verified by Powder X-ray diffraction (PXRD) analysis. The mechano-induced state can be easily recovered through a recrystallization process, which can be activated by solvent fumigation or solvent immersion. Furthermore, the switching between two emission states shows nice reversibility. Based on the MCF material with high fatigue resistance, a new type of rewritable optical data storage (ODS) is developed. Binary data, comprised of 0 and 1 state, can be matched well with the two emission states, respectively. The data could thus be written or erased on the ODS device, demonstrating feasibility and practicability.