Dynamically photo-tunable multicolor luminescence of supramolecular gel based on fluorescent gelator and used for information encryption

The ingenious collaboration of photo-isomerized molecules and luminescent gelator can create self-supporting materials used for multi-level and multi-dimensional information encryption. Herein, a supramolecular gel (SDTD) was prepared by using photoluminescent gelator 1,3:2,4-di(benzylidene)-D-sorbitol (DBS), lanthanide ions (Tb3+), as well as reversible photo-isomerized diarylethylene (DTE), and spiropyran (SP) derivative. Rheological studies showed that the prepared SDTD gel possessed good self-supporting ability owing to the 3D network structure formed by DBS aggregates. Additionally, SDTD gel displayed dynamic multicolor luminescence due to the presence of three luminescent centers including DBS, Tb3+, and MC-o (the photoisomer of SP). The luminescent color of SDTD gel can be easily tuned by irradiation wavelengths and time. It was found that a photo-tunable fluorescence resonance energy transfer (FRET) occurred between Tb3+ and MC-o, Tb3+ and DTE-c (the photoisomer of DTE), the corresponding FRET efficiency was 47 % and 52 %, respectively. The results also indicated that the photo-tunable inner filter effect (IFE) occurred between DBS and DTE-c, DBS and MC-o, respectively, which endowed SDTD gel with dynamically photo-tunable multicolor luminescence capability. SDTD gel has the advantages of simple preparation, low cost, and flexible luminescence regulation. In addition, based on the multicolor luminescence of SDTD gel, a new method of multi-dimensional information encryption was proposed, which shows a potential application in the field of anti-counterfeiting materials.