An efficient and stable fluorescent graphene quantum dot–agar composite as a converting material in white light emitting diodes

Abstract

Experimental processPreparation of water-soluble GQDs: The water-soluble GQDs were prepared by microwave-assisted hydrothermal pyrolysis method. The glucose (Sigma-Aldrich, > 99.5%) was dissolved in deionized water with the concentration of ~11 wt%. The solutions were tapped to the glass bottle with tightened cover. The glass bottle was heated with a conventional microwave oven (Galanz P70B17L-T1) at a power of 595 W for a specific time (1, 3, 5, 7 and 9 min). Followed by the microwave irradiation, the GQD solutions were cooled down to room temperature under air ambient without further purification.Preparation of GQD/agar composite: 10 mg of agar flakes (Chancevon Agar) was inserted into 2 mL of the GQD solution at 85°C under vortex mixing. The mixture was well stirred and heated until it became homogeneous with the solution.Subsequently the mixture was poured into a 0.8 cm diameter glass tube mound and was cooled down to room temperature under ambient atmosphere.

Spectroscopic Investigation of Interaction Between Carbon Quantum Dots and D-Penicillamine Capped Gold Nanoparticles

“…In the past few years, various researchers have demonstrated the potential applications of fluorescent CQDs in bioimaging [10][11][12][13][14][15][16], lightemitting devices [17], sensors [18,19], and photovoltaics [20][21][22]. Compared to conventional quantum dots carbon based fluorescent materials are superior with respect to chemical stability and biocompatibility [23,24].…”

Dual-Mode SERS-Fluorescence Immunoassay Using Graphene Quantum Dot Labeling on One-Dimensional Aligned Magnetoplasmonic Nanoparticles

“…[15][16][17][18][19] Moreover, their strong quantum confinement and edge effects are advantages for electronic and optoelectronic applications. 20,21 In particular, Raman spectra of graphene have been well studied in visible wavelengths.…”

Chlorine doped graphene quantum dots: Preparation, properties, and photovoltaic detectors

“…After treating with HCl, however, additional two new peaks appeared at 238 nm (5.20 eV) and 197 nm (6.28 eV). The absorption peak of 238 nm is caused by p!p* transition of C¼C bond, 1,24 and the peak at 197 nm is due to r!p* transition, 11 where the energy difference (dE) between the p and r orbitals is near 1.08 eV. 11,12,25 dE should be below 1.5 eV for a triplet ground state.…”