Reversible fluorescence modulation of spiropyran-functionalized carbon nanoparticles

Abstract

Fluorescent carbon nanoparticles (CNPs) with diameters of about 3 nm which can emit blue-green light were synthesized through the hydrothermal carbonization of ethylenediaminetetraacetic acid disodium salt (EDTA·2Na). Then, the CNPs were functionalized with spiropyrans to obtain the spiropyran-functionalized CNPs. The emission of the spiropyran-functionalized CNPs centered at 510 nm could be switched off, while being turned on at 650 nm via energy transfer after UV light irradiation. The process could be reversed by using visible light irradiation. The optical switching of the fluorescence was repeated 10 times without apparent “fatigue”, showing excellent photoreversibility and high stability. Spiropyran-functionalized CNPs may find potential applications in biological imaging and labeling, reversible data storage/erasing, as well as individual light-dependent nanoscale devices.