A rational design of carbon dots via the combination of nitrogen and oxygen functional groups towards the first NIR window absorption

Abstract

Carbon Dots (CDs) that exhibited a First Near Infra-red (NIR) Window absorption was designed by a combination of Nitrogen and Oxygen surface functional groups. The Time-Dependent Density Functional Theory (TD-DFT)...

Revealing the synergetic interaction between amino and carbonyl functional groups and their effect on the electronic and optical properties of carbon dots

“…Thus, a charge transfer is more responsible for tuning the CDs' optical and electronic properties. 1,14,19 The amino and carbonyl groups were simultaneously functionalized in bottom-up preparation on the CDs' surface. 19,24,49 Then, it is highly intriguing to utilize their presence to tune the CDs' optical and electronic properties.…”

“…1,14,19 The amino and carbonyl groups were simultaneously functionalized in bottom-up preparation on the CDs' surface. 19,24,49 Then, it is highly intriguing to utilize their presence to tune the CDs' optical and electronic properties. The amino CDs-CQO with the N/O atomic ratios ranging from 0.5 to 2.0 were evaluated.…”

“…For all Amino CDs-CQO with varying the N/O atomic ratios, all carbonyl groups (fragments 1 and 2) show a high electron concentration, indicating the withdrawal behaviour as reported elsewhere. 12,19,30 Carbonyl groups withdraw the electrons from the closest fragment. For instance, in Amino CDs-CQO, the carbonyl groups (fragment 1) withdraw electrons from the closest fragment that is aromatic sp 2 carbon with amino groups present (fragment 6), leaving fragment 6 with a high hole concentration (Fig.…”

“…9,[11][12][13][14][15] This knowledge significantly broadens the potential application of CDs in various applications, such as energy conversion, catalysis, and biomedicine. [16][17][18][19][20] For example, as is well known, the absorption peaks of CDs are mainly in the UV and visible light regions. [21][22][23] Then, our groups utilized a large amount of nitrogen source to broaden the CDs' absorption from UV-Vis to the first NIR window region (650-900 nm), which opened a new potential application as a photothermal agent in photothermal therapy.…”

“…In our previous work, we designed CDs to tailor their absorption properties in the first NIR window region for biomedical applications. 19 The combination of pyrrolic-N and carbonyl groups shifted the CDs' absorption peak to a longer wavelength spanning the first NIR window region. 19 This study revealed that the combination of pyrrolic-N and carbonyl groups strongly influences the optical properties, especially the absorption properties.…”