Point-defect engineering on phosphorene quantum dots for DNA bases adsorption and sensor performance

We have performed density functional theory (DFT) calculations to understand the interaction of DNA bases with pristine and point-defective black phosphorus quantum dots (BPQDs). The point-defect BPQDs show improved affinity for guanine molecule, and therefore are beneficial for guanine adsorption. More interestingly, the point defects in BPQDs can enhance the sensitivity to some extent for guanine, because the significant energy gap changes have occurred after the adsorption. The orbital hybridization near the Fermi energy level leads to significant energy gap changes in the point-defect BPQDs. Electron density topological analyses indicate that the electrostatic interactions play an important role in the stabilizing between base molecules and substrates. [Display omitted] •DNA bases can be adsorbed on SV and DV BPQDs through physisorption state.•The electronic structures of SV and DV BPQDs are significantly altered upon guanine adsorption.•The electrostatic interactions were revealed by QTAIM and IGM.•The orbital interaction between guanine and defect BPQDs is significant.