Highly luminescent graphene core N-doped carbon nanodots prepared under spatial nanoconfinement

• Published in: Materials chemistry and physics 2023-10, Vol.307, p.128151, Article 128151
• Main Authors: Mikhraliieva, Albina, Nazarkovsky, Michael, Aucelio, Ricardo Queiroz, Xing, Yutao, Zaitsev, Volodymyr
• Format: Article
• Language: English
• Subjects: Carbon nanodots; Nanoreactor; Photoluminescence; Spatial isolation
• ISSN: 0254-0584
• DOI: 10.1016/j.matchemphys.2023.128151

Nitrogen-dopped carbon nanodots (CNDs) with an extremely high quantum yield of photoluminescence (up to 95%) have been obtained by thermal treatment of citric acid embedded in the porous structure of silica with immobilized N-[3-(Trimethoxysilyl)propyl]ethylenediamine. Spatial isolation of molecular precursors in nanoreactors permits the preparation of high-quality nanoparticles with spheroidal geometry and size 2–5 nm. The particles obtained at 110–180 °C for 60–600 min demonstrate excitation-independent photoluminescence at 453 nm. HRTEM reveals that the CNDs demonstrate ordered crystalline structures of graphic materials, indicating the catalytic effect of the nanoreactor. The high-resolution XPS experiment proves the N-doping of CNDs with 4.0 at.% of nitrogen atoms incorporated into the graphene core as pyrrolic and ternary fragments. [Display omitted] •Extremely high photoluminescent CNDs were obtained at 100–180 °C from citric acid embedded in ethylenediamine silica.•The CNDs have spheroidal geometry of the particles with a size in the range of 2–5 nm.•Nitrogen atoms incorporate the graphene core as pyrrolic and ternary moieties.•The CNDs demonstrate excitation-independent photoluminescence at 453 nm.•HRTEM reveals ordered crystalline structures in the CNDs with interplanar distances typical for multilayer graphene.