TY  - JOUR
A1  - Meiling, Till Thomas
A1  - Schürmann, Robin Mathis
A1  - Vogel, Stefanie
A1  - Ebel, Kenny
A1  - Nicolas, Christophe
A1  - Milosavljevic, Aleksandar R.
A1  - Bald, Ilko
T1  - Photophysics and Chemistry of Nitrogen-Doped Carbon Nanodots with High Photoluminescence Quantum Yield
JF  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - Fluorescent carbon nanodots (CNDs) are very promising nanomaterials for a broad range of applications because of their high photostability, presumed selective luminescence, and low cost at which they can be produced. In this respect, CNDs are superior to well-established semiconductor quantum dots and organic dyes. However, reported synthesis protocols for CNDs typically lead to low photoluminescence quantum yield (PLQY) and low reproducibility, resulting in a poor understanding of the CND chemistry and photophysics. Here, we report a one-step synthesis of nitrogen-doped carbon nanodots (N-CNDs) from various carboxylic acids, Tris, and ethylenediaminetetraacetic acid resulting in high PLQY of up to 90%. The reaction conditions in terms of starting materials, temperature, and reaction time are carefully optimized and their influence on the photophysical properties is characterized. We find that citric acid-derived N-CNDs can result in a very high PLQY of 90%, but they do not show selective luminescence. By contrast, acetic acid-derived N-CNDs show selective luminescence but a PLQY of 50%. The chemical composition of the surface and core of these two selected N-CND types is characterized among others by high-resolution synchrotron X-ray photoelectron spectroscopy using single isolated N-CND clusters. The results indicate that photoexcitation occurs in the N-CND core, whereas the emission properties are determined by the N-CND surface groups.
Y1  - 2018
U6  - https://doi.org/10.1021/acs.jpcc.8b00748
SN  - 1932-7447
VL  - 122
IS  - 18
SP  - 10217
EP  - 10230
PB  - American Chemical Society
CY  - Washington
ER  -