Multifunctional AIE-ESIPT dual mechanism tetraphenylethene-based Schiff base for inkless rewritable paper and a colorimetric/fluorescent dual-channel Zn²⁺ sensor

Organic fluorescent materials have attracted extensive interests due to their wide applications. However, many organic fluorescent materials are single functional and suffer from complicated synthesis and purification, which significantly limits their practical applications. Herein, a multifunctional tetraphenylethene-based Schiff base (TPESB) was designed via a combination of AIE and ESIPT mechanisms and facilely developed through a one-pot reaction of two commercially available compounds, which exhibit dramatic absorption/fluorescence dual-mode color changes induced by water and zinc ions. By employing TPESB as an imaging layer and water as an ink, an eco-friendly inkless rewritable paper was developed showing great potential application in anti-counterfeiting and information security. Moreover, TPESB can serve as a colorimetric/fluorescent dual-channel sensor for Zn2+ ions with high sensitivity, high selectivity, fast response time, and low detection limit (38.9 nM). Additionally, TPESB displays low cytotoxicity and has been successfully applied for sensing of Zn2+ in living cells. The presented strategy will provide a reference for developing multifunctional materials and expanding their wider application fields.