Reversible and color-variable afterglow luminescence of carbon dots triggered by water for multi-level encryption and decryption

Abstract Stimulus-responsive smart afterglow materials with color-variable and reversible switch feature are urgently expected in view of actual application needs in the field of sensing, anti-counterfeiting, optoelectronic devices etc. Herein, we report a facile and effective construction strategy for preparing blue afterglow smart carbon dots nanomaterials (TPA-CDs/Si) by constructing Si-C covalent bonds within CDs utilizing silicon as doping element, displaying color-variable afterglow feature (blue to green) triggered by water owing to the formation of bridging hydrogen-bonded networks among TPA-CDs/Si nanocomponents connected by water molecule after the introduction of water. Such materials also realize reversible multi-level information encryption application via alternately adding water and heating owing to the formation and breaking of bridging hydrogen-bonded networks among TPA-CDs/Si nanocomponents in the presence and absence of water.