Fluorescence and Nonlinear Optical Response of Graphene Quantum Dots Produced by Pulsed Laser Irradiation in Toluene

Abstract

Graphene quantum dots (GQDs), the zero dimensional (0D) single nanostructures, have many exciting technological applications in diversified fields such as sensors, light emitting devices, bio imaging probes, solar cells, etc. They are emerging as a functional tool to modulate light by means of molecular engineering due to its merits, including relatively low extend of loss, large outstretch of spatial confinement and control via doping, size and shape. In this article, we present a one pot, facile and ecofriendly synthesis approach for fabricating GQDs via pulsed laser irradiation of an organic solvent (toluene) without any catalyst. It is a promising synthesis choice to prepare GQDs due to its fast production, lack of byproducts and further purification, as well as the control over the product by accurate tuning of laser parameters. In this work, the second (532 nm) and third harmonic (355 nm) wavelengths of a pulsed nanosecond Nd:YAG laser have been employed for the synthesis. It has been found that the obtained GQDs display fluorescence and is expected to have potential applications in optoelectronics and light-harvesting devices. In addition, nonlinear optical absorption of the prepared GQDs was measured using the open aperture z-scan technique (in the nanosecond regime). These GQDs exhibit excellent optical limiting properties, especially those synthesized at 532 nm wavelength.

Impact of Photonic Band Edge Enabled Slow Light Effect on Optical Limiting Activity of Graphene Quantum Dots in All Polymer 1-D Photonic Crystals

“…It is characterized by the existence of a dominant peak ∼287 nm, and it is attributed to the π to π* transition in aromatic C–C bonds. The closer analysis of the absorption spectrum reveals a small shoulder peak ∼335 nm due to n –π* of the CO bond, normally seen in graphene . The emission spectrum of the synthesized GQD by pulsed laser irradiation of toluene is given in Figure a.…”

“…The interaction of the 532 nm laser pulse with toluene leads to the formation of a highly non-equilibrium state due to the generation of intense heat and pressure. The decomposition of toluene leads to the formation of stable and charged carbon as well as hydrogen constituents, and the growth of this fragmented species leads to the formation of GQDs …”

“…The two-photon absorption behavior of graphene-related material has previously been reported. Kalarikkal et al reported the nanosecond Z -scan studies of GQD prepared by the laser ablation technique . They reported the use under ns pulse excitations, effective two-photon absorption to be the most effective NLA mechanism.…”

“…The obtained images are shown in Figure 2b, and most of the GQD structure has a size of less than 5 nm with an average size of 3.7 nm (Figure 2d). The HR-TEM image reveals the details about interplanar spacing, and it is found to be ∼0.21 nm that corresponds to 100 planes of graphene 32 (Figure 2c).…”

Folic Acid-decorated and PEGylated Graphene Quantum Dots as efficient Tamoxifen delivery system against breast cancer cells: in vitro studies

“…The vibrational broad band at 3412 cm −1 was detected because of overlapped O-H and N-H bonds of FA and GQDs. The absorption bands at around 2868 cm −1 , 2931 cm −1 , 2965 cm −1 , 3020 cm −1 , and 3049 cm -1 were related to stretching modes of aliphatic and aromatic C-H bonds in TMX and other structural components of nanocarriers [27].…”