Photo-Stimuli-Responsive Dual-Emitting Luminescence of a Spiropyran-Encapsulated Metal-Organic Framework for Dynamic Information Encryption

The development of photo-stimuli-responsive luminescent materials is essential to address emerging demands in encryption security. Here, a novel photo-stimuli-responsive dual-emitting luminescent material ZJU-128 superset of SP (SP = spiropyran) is reported, which is obtained by encapsulating spiropyran molecules into a cadmium-based metal-organic framework (MOF), [Cd-3(TCPP)(2)]center dot 4DMF center dot 4H(2)O (ZJU-128, H4TCPP = 2,3,5,6-tetrakis (4-carboxyphenyl)pyrazine). This MOF/dye composite ZJU-128 superset of SP exhibits a blue emission from the ligand of ZJU-128 at 447 nm and a red emission around 650 nm from spiropyran. Utilizing the photoisomerization of spiropyran from ring-closed to ring-open form under UV-light irradiation, significant fluorescence resonance energy transfer (FRET) process between ZJU-128 and spiropyran is achieved. As a result, the blue emission of ZJU-128 is gradually decreased while the red emission of spiropyran increases. This dynamic fluorescent behavior can fully recover to the original state following exposure to visible light (>405 nm). By taking advantage of the time-dependent fluorescence, dynamical anti-counterfeiting patterns and multiplexed coding are successfully developed based on ZJU-128 superset of SP film. This work provides an inspiring point for the design of information encryption materials with higher security requirements.

Automated summary

A novel photo-stimuli-responsive dual-emitting luminescent material ZJU-128 superset of SP is reported, which is obtained by encapsulating spiropyran molecules into a cadmium-based metal-organic framework (MOF). The MOF/dye composite exhibits blue and red emissions from ZJU-128 and spiropyran, respectively. Utilizing the photoisomerization of spiropyran, fluorescence resonance energy transfer (FRET) process is achieved, enabling the development of dynamic anti-counterfeiting patterns and multiplexed coding based on ZJU-128 superset of SP film.