Gram-scale synthesis of single-crystalline graphene quantum dots with superior optical properties

Abstract

Graphene quantum dots (GQDs) have various alluring properties and potential applications, but their large-scale applications are limited by current synthetic methods that commonly produce GQDs in small amounts. Moreover, GQDs usually exhibit polycrystalline or highly defective structures and thus poor optical properties. Here we report the gram-scale synthesis of single-crystalline GQDs by a facile molecular fusion route under mild and green hydrothermal conditions. The synthesis involves the nitration of pyrene followed by hydrothermal treatment in alkaline aqueous solutions, where alkaline species play a crucial role in tuning their size, functionalization and optical properties. The single-crystalline GQDs are bestowed with excellent optical properties such as bright excitonic fluorescence, strong excitonic absorption bands extending to the visible region, large molar extinction coefficients and long-term photostability. These high-quality GQDs can find a large array of novel applications in bioimaging, biosensing, light emitting diodes, solar cells, hydrogen production, fuel cells and supercapacitors.

Tuning the Photoluminescence of Graphene Quantum Dots by Fluorination

“…GQDs were prepared in large scale through a bottom-up method as reported elsewhere [20]. F-GQDs were synthesized by mixing GQDs and XeF 2 via a gaseous phase heating route.…”

Facile and size-controllable preparation of graphene oxide nanosheets using high shear method and ultrasonic method

“…GO has recently attracted substantial interest as a possible intermediate for the preparation of graphene [11][12][13] and metal oxide/graphene nanocomposites [14][15][16]. It also has been used to prepare a strong paper-like material owing mainly to their interesting electrical, thermal, mechanical and optical properties [1,8,10,[17][18][19][20][21][22]. The small area of GO sheets results in high inter-sheet contact resistance in the films due to a large amount of intersheet junctions [10,23,24].…”

Properties and Synthesis Strategies of Graphene Quantum Dots

“…GQDs fabricated by hydrothermal treatment of trinitropyrene even exhibit PL. 15 Furthermore, the intensity and brightness of photoluminescence are markedly enhanced upon 3 h continuous exposure under 100 W xenon lamp. In contrast, semiconductor QDs usually show a typical photobleaching effect under the same condition.…”