CONTROL THE SURFACE CHEMISTRY OF CARBON NANODOTS  BY ENGINEERING THE PRECURSOR ACID/AMINE RATIO

Phạm Thị Thu Trang; Trần Thị Khánh Linh; Bùi Huy Hoàng; Mai Xuân Dũng; Trần Khánh Hòa; Vũ Thị Phương Anh; Nguyễn Văn Hảo; Nguyễn Thị Thanh

doi:10.34238/tnu-jst.12097

CONTROL THE SURFACE CHEMISTRY OF CARBON NANODOTS BY ENGINEERING THE PRECURSOR ACID/AMINE RATIO

About this article

Received: 20/02/25 Revised: 05/05/25 Published: 05/05/25

Authors

1. Pham Thi Thu Trang , Vietnam Military Medical University
2. Tran Thi Khanh Linh, Vietnam Military Medical University
3. Bui Huy Hoang, Hanoi Pedagogical University 2
4. Mai Xuan Dung, Hanoi Pedagogical University 2
5. Tran Khanh Hoa, Thuy Loi University
6. Vu Thi Phuong Anh, TNU - University of Sciences
7. Nguyen Van Hao, TNU - University of Sciences
8. Nguyen Thi Thanh, Vietnam National University of Agriculture

Abstract

Controlling the surface functional groups of carbon nanodots is important to deploy carbon nanodots in various applications, such as visible-light photocatalysts, nanobiosensors, and multifunctional materials. In this study, we prepared a series of carbon nanodots by hydrothermal treatment mixtures of citric acid and ethylenediamine with different citric acid/ethylenediamine ratios. By using Fourier transform infrared, photoluminescent, and UV-Vis spectroscopies, it was demonstrated that the surface chemistry of carbon nanodot changed from carboxy-rich to amino-rich when the citric acid/ ethylenediamine ratio decreased. All carbon nanodots had a common absorption band at about 350 nm while their emission quantum yield varied from 2.5% to 63.0%. Theoretical calculations suggest that the energy levels of HOMO and LUMO of carboxy functionalized carbon nanodots were lower than those of amino-functionalized carbon nanodots while their bandgaps were similar. These research results provide important information for designing carbon nanodots for targeted applications.

Keywords

Carbon dots; Functional group; Surface chemistry; Hydrothermal; Energy levels

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DOI: https://doi.org/10.34238/tnu-jst.12097

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