Tetraphenylethylene @ Graphene Oxide with Switchable Fluorescence Triggered by Mixed Solvents for the Application of Repeated Information Encryption and Decryption

• Published in: ACS applied materials & interfaces 2019-09
• Main Authors: Qin, Mengmeng, Xu, Yuxiao, Gao, H, Han, Guoying, Cao, Rong, Guo, Peili, Feng, Wei, Chen, Li
• Format: Article
• Language: English
• ISSN: 1944-8252
• DOI: 10.1021/acsami.9b12421

Aggregation-induced emission (AIE) materials present unique solid-state fluorescent. However, there remains challenge in the switching of fluorescence quenching/emitting of AIE materials, limiting the application in information encryption. Herein, we report a composite of tetraphenylethylene@graphene oxide (TPE@GO) with switchable microstructure and fluorescence. We choose GO as fluorescence quencher to control the fluorescence of TPE by controlling the aggregation structure. Firstly, TPE coating with average thickness of about 31 nm was deposited at GO layer surface, which is the critical thickness that the fluorescence can be largely quenched due to the fluorescence resonance energy transfer. After spraying a mixed solvent (good and poor solvent of TPE) on the TPE@GO, blue fluorescence of TPE can be emitted in the drying process. During the treating of mixed solvents, the planar TPE coating was dissolved in THF firstly, and then the TPE molecules aggregated into nanoparticles (average diameter of 65 nm) in H2O during the volatilization of THF. We found the fluorescence switching of the composite is closely related to the microstructure change of TPE between planar and granular structures, which could make the upper TPE molecules in and out of the effective quenching region of GO. This composite, along with the treating method was used as invisible ink in repeated information encryption and decryption. Our work not only provides a simple strategy to switch the fluorescence of solid-state fluorescent materials but also demonstrates the potential for obtaining diverse material structures through compound solvents treating.