Pineapple Peel-Derived Carbon Dots: Applications as Sensor, Molecular Keypad Lock, and Memory Device.

Herein, the fluorescent carbon dots (CDs) with blue emission were prepared by hydrothermal treatment using pineapple peel as a source of carbon. The as-prepared CDs exhibited turn-Off fluorescence behavior toward Hg and subsequent turn-On behavior for l-cysteine along with enhanced biocompatibility and negligible cytotoxicity for cell imaging. The practical applicability of carbon dots was used for the quantification of Hg in water. On the basis of the spectral characteristic changes, we have designed individual elementary logic operations such as NOT and IMP gates, by utilizing CD as probe and Hg and l-Cys as chemical inputs. We have also demonstrated the utility of this system in electronic security devices and as memory element, with the idea of the switching.