A Simple Approach of CQDs@MoS<sub>2</sub> Nanosheets for Turn-On Fluorescence Sensor for Detection of Pb<sup>2+</sup> Ions

The 2-Dimennsionnal nanocomposites are applied for the ennhannced fluorescence sensor for analysing heavy metal ions is explored using a simple novel technique based on green manufactured (CQDs@MoS 2 ) nanocomposite. The emission intensity of CQDs have a better dispersibility, and MoS 2 nanosheets have an excellent exfoliation, allowing the CQDs to adhere to the surface and form a label-free sensors. The emission peak of CQDs was quenched by transferring non-radiative energy as of CQDs to MoS 2 sheets in an excited state. However, when metal ions are included in the CQDs@MoS 2 nanocomposite, it develops a solid surface combined with the carbon dots nanosheets, that might aid in CD recovery. More intriguingly, the sensing performance of MoS 2 nanosheets were examined at various pH levels to better recognize the change in surface charge, which resulted in significantly improved responsiveness for identification of Pb (II) ions with LODs of 0.9 nM. Furthermore, it is suggested that present method are intended to be quick, easy, cost effective, environmental friendly for sensing heavy metal ions.