Investigation of the role of pH and the stoichiometry of the N-dopant in the luminescence, composition and synthesis yield of carbon dots

• Type: Article in International Scientific Journal
• Date: 2023

Authors

Luís Pinto da Silva (Author) FCUP; Joaquim C G E Esteves da Silva (Author) FCUP; Diana Crsita (Author) Other; Manuel Algarra (Author) Other; Maria Valle Martínez de Yuso (Author) Other

Journal

Title: Journal of Materials Chemistry B

Vol. 11

Pages: 1131-1143

ISSN: 2050-7518

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 4 Citations

Associated Projects

CIQUP - Financiamento Plurianual da Unidade de I&D CIQUP - Centro de Investigação em Química da Universidade do Porto

Other information

Authenticus ID: P-00X-R8P

DOI: 10.1039/d2tb02318k

Abstract (EN): Carbon dots (CDs) are carbon-based nanoparticles with very attractive luminescence features, which simplicity and flexibility of their fabrication can lead to an endless number of CDs with distinct properties and applications. High fluorescence quantum yields (QY(FL)) are generally a necessary feature for various applications of CDs. One commonly employed strategy to improve the fluorescence properties of CDs is heteroatom-doping using precursors containing desired heteroatoms (with focus on N-doping). In this work, we report the synthesis and systematic investigation of an array of N-doped CDs, obtained from the dry heating of solid mixtures of glucose and urea in different molar ratios with two main objectives: to study the role of stoichiometry in the optical properties and composition of CDs and to investigate the formation of possible alkaline-responsive nanoparticles and the potential of this procedure for obtaining CDs with higher synthesis yields. We have characterized the optical properties of this diverse array of glucose and urea-based CDs using both UV-Vis and fluorescence spectroscopies. In addition, we have also examined the CDs by using high-resolution transmission electron microscopy (HR-TEM) and X-Ray photoelectron (XPS) spectroscopy, as well as by assessing the thermal stability of the nanoparticles. We have found that this fabrication process generates two types of CDs, one readily soluble in water and other only soluble at basic pH. The latter was characterized by higher synthesis yields, and lower QY(FL) and thermal stability, when compared with those of the former. Furthermore, the stoichiometry of the N-dopant does not appear to be correlated with the QY(FL) of the obtained CDs. This study provides novel information that should be useful for the future rational development of CDs with higher QY(FL) and synthesis yields.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13