Please use this identifier to cite or link to this item:
Type
ArticleCopyright
Open access
Collections
- IOC - Artigos de Periódicos [12820]
Metadata
Show full item record
RATIONAL DESIGN OF LARGE FLAT NITROGEN-DOPED GRAPHENE OXIDE QUANTUM DOTS WITH GREENLUMINESCENCE SUITABLE FOR BIOMEDICAL APPLICATIONS
Grandes planos dopados com nitrogênio
Pontos quânticos de óxido de grafeno
Luminescência verde
Adequado para aplicações biomédicas
Doped graphene
Oxide quantum dots
With greenluminescence
Suitable for biomedical applications
Author
Affilliation
Abstract
Rational synthesis and simple methodology for the purification of large (35–45 nm in lateral size) and flat
(1.0–1.5 nm of height) nitrogen-doped graphene oxide quantum dots (GOQDs) are presented. The
methodology allows robust metal-free and acid-free preparation of N-GOQDs with a yield of about
100% and includes hydrothermal treatment of graphene oxide with hydrogen peroxide and ammonia. It
was demonstrated that macroscopic impurities can be separated from N-GOQD suspension by their
coagulation with 0.9% NaCl solution. Redispersible in water and saline solutions, particles of N-GOQDs
were characterized using tip-enhanced Raman spectroscopy (TERS), photoluminescent, XPS, and UV-VIS
spectroscopies. The size and morphology of N-GOQDs were studied by dynamic light scattering, AFM,
SEM, and TEM. The procedure proposed allows nitrogen-doped GOQDs to be obtained, having 60–51%
of carbon, 34–45% of oxygen, and up to 7.2% of nitrogen. The N-GOQD particles obtained in two hours
of synthesis contain only pyrrolic defects of the graphene core. The fraction of pyridine moieties grows
with the time of synthesis, while the fraction of quaternary nitrogen declines. Application of TERS allows
demonstration that the N-GOQDs consist of a graphene core with an average crystallite size of 9 nm
and an average distance between nearest defects smaller than 3 nm. The cytotoxicity tests reveal high
viability of the monkey epithelial kidney cells Vero in the presence of N-GOQDs in a concentration
below 60 mg L 1. The N-GOQDs demonstrate green luminescence with an emission maximum at
505 nm and sedimentation stability in the cell culture medium.
Keywords in Portuguese
Projeto racionalGrandes planos dopados com nitrogênio
Pontos quânticos de óxido de grafeno
Luminescência verde
Adequado para aplicações biomédicas
Keywords
Rational design of large flat nitrogenDoped graphene
Oxide quantum dots
With greenluminescence
Suitable for biomedical applications
Share