One-step microwave synthesis of N-doped hydroxyl-functionalized carbon dots with ultra-high fluorescence quantum yields

Abstract

A one-step microwave synthesis of N-doped hydroxyl-functionalized carbon dots (CDs) with ultra-high fluorescence quantum yields (QYs) of 99% is reported. These ultra-high QY CDs were synthesized using citric acid and amino compound-containing hydroxyls like ethanolamine and tris(hydroxylmethyl)aminomethane. Amino and carboxyl moieties can form amides through dehydration condensation reactions, and these amides act as bridges between carboxyl and hydroxyl groups, and modify hydroxyl groups on the surface of the CDs. The entire reaction can be carried out within 5 min. When the molar ratio of reactants is 1 : 1, the hydroxyl and graphitic nitrogen content is the highest, and the synergy leads to a high ratio between the radiative transition rate and nonradiative transition rate as well as a high QY. The developed pathway to N-doped hydroxyl-functionalized CDs can provide unambiguous and remarkable insights into the design of highly luminescent functionalized carbon dots, and expedite the applications of CDs.

Confined Synthesis of Carbon Nitride in a Layered Host Matrix with Unprecedented Solid‐State Quantum Yield and Stability

“…Especially in recent years, carbon dots (CDs) and graphene quantum dots (GQDs) have drawn tremendous attention for their high aqueous solubility, facile preparation, and low toxicity; and prospective applications have been explored in bioimaging, photocatalysis, photovoltaic, and optoelectronic devices . Great efforts have been made to promote the photoluminescence quantum yield (PLQY) of CDs and GQDs, which is a crucial factor in practical applications . However, previous studies on nanocarbon fluorescent materials are mainly focused on aqueous or colloid systems; solid‐state quantum yield (SSQY) decreases sharply as a result of aggregation‐induced PL quenching, which restricts their employment in solid state devices (e.g., light‐emitting diodes (LEDs), optoelectronic devices) .…”

One‐Pot Synthesis of Highly Fluorescent Carbon Dots from Spinach and Multipurpose Applications

“…Their diameters are in the range of 1.0 to 5.0 nm (Figure B‐b and Figure S1 in the Supporting Information). The HRTEM images reveal lattice spacings of 0.21 and 0.34 nm, which correspond to the (100) and (002) facets of graphitic carbon, as shown in the insets of Figure B‐a ,…”

Blue luminescent amorphous carbon nanoparticles synthesized by microplasma processing of folic acid

“…It is confirmed that the fluorescence emission of C-NPs may be influenced by a range of factors involving nanoparticle size, surface functionalization, and presence of surface defects, etc. [15][16][17][18] In this paper, the size of the produced FA C-NPs (approx. 47 nm) is much bigger than that of the reported C-dots (<10 nm).…”