Chapter 10 - Carbon nitride-based optical sensors for metal ion detection

Abstract

Graphitic carbon nitride quantum dots (g-CN QDs) have attracted the global scientific community due to its unique properties such as biocompatibility, easy functionalization, resistant to photobleaching, high water stability, high quantum yield, chemical stability, and most importantly high photoluminescence that makes this material an excellent choice in visible-light-driven applications, e.g., photocatalysis, photodegradation, photovoltaics, water splitting, and optical sensing. The present chapter focuses on the sensing application of pristine g-CN QDs and doped g-CN QDs in recent years. Pristine g-CN QDs, due to similar structural and optical properties, predominantly display sensing behavior toward Hg2+ ions. However, the selectivity of the present optical probes, i.e., g-CN QDs can be tailored either by induction of metal ion binding functionality at the surface or by doping or through both functionalization and doping. These modifications have significant effect on the optical properties by the introduction of either surface defect or interstitial states in between electron hole that leads to enhanced selectivity in the sensing application of g-CN QDs.