Dynamic fluorescent switches with multiple light outputs offer promising opportunities for advanced security encryption. However, the achievement of dynamic emission, particularly when based on the timing of external stimuli, continues to present a significant challenge. Herein, a unique dynamic fluorescent switch was developed by integrating spiropyran molecules (SP) into a core-shell structure (SiO@Tb-MOF).
View Article and Find Full Text PDFHere, we report a novel invisible ink with different decay times based on thin films with different molar ratios of spiropyran (SP)/Si, which allows the encryption of messages over time. Nanoporous silica has been found to be an excellent substrate to improve the solid photochromism of spiropyran, but the hydroxyl groups of silica have a serious effect on fade speeds. The density of silanol groups in silica has an influence on the switching behavior of spiropyran molecules, as they stabilize the amphiphilic merocyanine isomers and thus slow down the fading process from the open to the closed form.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2022
Developing smart fluorescent materials having very advanced levels, showing dynamic displays of encrypted messaging, remains a huge challenge. In this paper, we present a unique method based on combining a common photochromic molecule spiropyran (SP) with hydrogen-bonded organic frameworks (HOFs), which allows for reversible switching of SP in solid states and shows dynamic displays of encrypted information. With the irradiation time extended, the fluorescence emission undergo an evident transformation from yellow-green to orange to red, because of the fluorescence resonance energy transfer (FRET) process between the unique HOFs and merocyanine (MC) isomer.
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