DFT-D3 and TD-DFT studies on the sensor performance of the functionalized carbon quantum dots for curcumin

In the present study, the interaction of curcumin molecule with a series of functionalized carbon quantum dots (f-CQDs, f=-OH, -NH2, -COOH) was investigated for drug sensing purposes by using density functional theory (DFT) calculations. After functionalization, the adsorption capacity of CQDs for curcumin was improved to a certain extent. The quantum theory of atoms in molecules (QTAIM) and symmetry-adapted perturbation theory (SAPT) energy decomposition revealed that the dispersion force played a dominant role in the stabilizing. The energy gap of the CQDs was reduced through functionalization. The adsorption of curcumin led to a significant energy gap change especially for CQDs with -COOH functionalized (-21.39 %), suggesting its promising sensor performance to curcumin. The detection ability of CQDs and f-CQDs for curcumin was further assessed by simulating the ultra-violet visible (UV–vis) and infrared (IR) spectra.