Electrochromic materials can either be inorganic or organic, the latter being advantageous because both synthesis and processability are easier to control and more environmentally friendly. At the moment, only reversible organic chromogenic materials are available on the market, meaning materials that can go back and forth between their two coloured states. However, in security related applications for which anti-tamperability is of the utmost importance (e.g. smart labels for product monitoring), the possibility to lock the material in one of its two coloured state as a response to a secured activation or a stimulus, would prove extremely valuable.

By developing a high-performing, sustainable, and irreversible organic electrochromic formulation, the possible uses of electrochromic devices in security applications are hugely expanded. The material is characterized by a stark contrast between the initial, transparent state and the final coloured state, which is obtained in a very short time (i.e. < 5s) and with a very small energetic input (1.5 V). Most importantly, once the device is activated the initial transparent state can never be recovered. The innovation further comprises many other advantages such as the non-toxic and low-cost of the chromogenic material employed, and the naturally occurring dopamine molecule, enabling the production of sustainable and industrially relevant water-based formulations. Moreover, the persistence of the signal over months without the requirement of additive energetic input, further contributes to decreasing the environmental impact of this technology.