Redox regulation of electrofluorochromic behavior for an AIEgen-doped PVA hydrogel based on a ferrocene derivate

Redox stimulation at the molecular level has been the focus of many fields, especially in electrofluorochromic (EFC) devices with individually addressable pixels and switching function. In this study, the fluorescent molecule ((1E)-1-((4-(1,2,2-triphenylvinyl)benzylidene)-hydrazineylidene)ethyl)ferrocene (FcMe-TPE) with aggregation-induced emission (AIE) properties was synthesized and mixed with PVA to prepare an EFC hydrogel material (PVA/FcMe-TPE) with high conductivity. The obtained hydrogel exhibited reversible fluorescent switching behavior, which could be achieved by adding a redox agent alternately based on the redox properties of the FcMe-TPE molecule. The fluorescence intensity of the hydrogel increased by 700 times after adding oxidant and could almost return to the initial value by adding reductant. Interestingly, the effect of the oxidant could be replaced by applying a voltage and the hydrogel exhibited good EFC behaviors. When the voltage increased from 0 V to 1 V, the fluorescence intensity of the hydrogel gradually increased and reached the maximum value at 1 V. The obtained fluorescent hydrogels could be customized to different appearance according to needs, and the EFC devices with individually addressable pixels and switching function were fabricated successfully. Finally, by introducing phytic acid (PA), the mechanical strength of the PVA/FcMe-TPE hydrogel was greatly improved without affecting its EFC performance. This study provides a new idea and solution for the intelligent display field, such as advanced anti-counterfeiting and information encryption.