Ultrathin Graphitic Carbon Nitride Nanosheet: A Highly Efficient Fluorosensor for Rapid, Ultrasensitive Detection of Cu2+

A highly efficient fluorosensor based on ultrathin graphitic carbon nitride (g-C3N4) nanosheets for Cu2+ was, developed In the absence of metal ions, the nanosheets exhibit high fluorescence; the strong coordination of the Lewis basic sites on them to metal ions, however, Causes fluorescence quenching via photoinduced electron transfer leading to the qualitative and semiquantitative detection of metal ions. This fluorosensor exhibits high selectivity toward Cu2+. The whole detection process can be completed within 10 mm with a detection limit as low as 0.5 nM. The use of test paper enables the naked-eye detection of Cu2+ with a detection limit of 0.1 nmol. The practical use of this sensor for Cu2+ determination in real water samples was also demonstrated.