Facile and Highly Effective Synthesis of Controllable Lattice Sulfur-Doped Graphene Quantum Dots via Hydrothermal Treatment of Durian

Abstract

Recently, the biomass "bottom-up" approach for the synthesis of graphene quantum dots (GQDs) has attracted broad interest because of the outstanding features, including low-cost, rapid, and environmentally friendly nature. However, the low crystalline quality of products, substitutional doping with heteroatoms in lattice, and ambiguous reaction mechanism strongly challenge the further development of this technique. Herein, we proposed a facile and effective strategy to prepare controllable sulfur (S) doping in GQDs, occurring in a lattice substitution manner, by hydrothermal treatment of durian with platinum catalyst. S atoms in GQDs are demonstrated to exist in the thiophene structure, resulting in good optical and chemical stabilities, as well as ultrahigh quantum yield. Detailed mechanism of the hydrothermal reaction progress was investigated. High-efficiency reforming cyclization provided by platinum was evidenced by the coexistence of diversified sp-fused heterocyclic compounds and thiophene derivatives. Moreover, we also demonstrated that saccharides in durian with small molecular weight (<1000 Da) is the main carbon source for the forming GQDs. Because of the desulfurizing process, controllable photoluminescence properties could be achieved in the as-prepared GQDs via tuning doping concentrations.

Biomass‐Derived Carbon Dots and Their Applications

“…HTC is a carbon nanomaterial synthesis technology, which has been widely used in many fields . HTC has been used to prepare novel carbon‐based materials from biomass carbon precursors such as sweet pepper, garlic, husks of nuts, papaya juice, rice husk, and other biomass materials …”

“…reported preparing fluorescent N‐doped BCDs by using dragon fruit as a carbon source and hydrothermal treatment at 180 °C for 12 h. The BCDs were spherical, and they have an average diameter of 2.5 nm. Durian is rich in a large amount of sulfide, using durian as the carbon source to prepare S‐doped BCDs by simple and effective hydrothermal method. The S‐doped BCDs are prepared by lattice substitution mechanism to control the doping.…”

“…Intense, defect‐related D, and G peaks are located near 1350 and 1580 cm −1 , respectively, while a 2D‐peak (~2700 cm −1 ) is strongly suppressed. The ratio between the D and G peak intensities is calculated to be approximately 0.32 …”

The Synthesis and Application of Nitrogen-Doped Graphene Quantum Dots on Brilliant Blue Detection

“…Luminescent properties of GQDs are depending on many factors such as size, shape, surface oxidation degree, and surface functionalization. Nowadays, the synthesis of heteroatom-(boron [14], sulfur [15], fluorine [16], phosphorus [17], and nitrogen [18]) doped GQDs has attracted increasing attention. Experimental results demonstrate that nitrogen is a good candidate for chemical doping of GQDs, because nitrogen with five valence electrons could react with graphene atoms to form strong valence bonds.…”

Environmental effects on the charge transfer properties of Graphene quantum dot based interfaces

“…Nitrogen as an n ‐type dopant improves the conductivity, transport features and magnetic properties and is therefore used in spintronics and nanoelectronics . In addition, they form stable interfaces with either donor or acceptor organic molecules . Apart from the photochemical properties, the appeal of such interfaces is due to the strong charge transfer (CT) which can be generated by tuning the properties of the absorbed organic molecules.…”