https://doi.org/10.1140/epjp/s13360-023-04811-7
Regular Article
Assessment of the correlation between optical properties and CQD preparation approaches
Physics Department, Faculty of Science, Cairo University, Giza, Egypt
Received:
13
August
2023
Accepted:
19
December
2023
Published online:
6
January
2024
Various production procedures, for carbon quantum dots (CQDs), are still being extensively researched to understand the nature of CQD luminescence. This study compares and examines the impact of chemical as well as green methods on the structural and optical properties of CQDs. We present a straightforward, cost-effective bottom-up method for producing fluorescent CQDs from lemon peels (L-CQDs), orange juice (O-CQDs), and citric acid (C-CQDs) without having to deal with time-consuming or ineffective post-processing processes. The proposed green synthesis has no toxic by-products, and the residual resources utilized promote the large-scale production of CQDs. X-ray diffraction, high-resolution transmission electron microscopy, FTIR, Raman, DLS, and UV–Vis spectroscopy are utilized to investigate the structure and optical characteristics of the prepared CQDs. The as-prepared CQDS possess small particle sizes of 5.6 nm, 6.2 nm, and 1.1 nm for L-CQDs, O-CQDs, and C-CQDs samples, respectively. FTIR results reveal the coexistence of carboxylic and hydroxyl groups on the surface of the CQDs, as also supported by zeta-potential values. Maximal fluorescence intensity was reached at excitation wavelengths of 365, 250, and 280 nm with an emission color of blue, indigo, and light blue for L-CQDs, O-CQDs, and C-CQDs, respectively. The presented approaches show a high quantum yield of 88% for O-CQDs, 49% for L-CQDs, and 37% for C-CQDs. Due to their minuscule particle size, perfect water solubility, high stability, and tunable luminescence properties, the prepared CQDs are preferred for potential applications in multicolor imaging, metal ion sensing, and wastewater technologies.
© The Author(s) 2024
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
