DFT investigation of aflatoxin B۱ adsorption on vacancy-defective graphene: electronic properties and sensing potential

Aflatoxins (AFs) are highly toxic compounds that pose substantial health risks, eliciting both Aflatoxin B۱ (AFB۱) is a highly toxic mycotoxin with severe health implications, necessitating rapid and sensitive detection methods. This study aims to investigate the potential of defect-engineered graphene nanosheets as electronic sensors for AFB۱ detection. Using density functional theory (DFT), the adsorption behavior of AFB۱ on perfect graphene (PG), single-vacancy graphene (SVG), and double-vacancy graphene (DVG) was systematically analyzed. The results reveal weak physisorption on PG, with minimal influence on electronic properties, whereas vacancy defects introduce reactive sites that markedly enhance adsorption strength and sensor response. In SVG, adsorption lowers the energy gap from ۰.۸۱ eV to ۰.۵۴ eV and decreases the work function from ۳.۵۷ eV to ۳.۵۳ eV, leading to increased conductivity and field emission current. Atoms in Molecules (AIM) analysis indicates that interactions are predominantly van der Waals in nature, confirming a physisorption-dominated mechanism. These findings demonstrate that single-vacancy defective graphene offers superior sensitivity and electronic modulation, underscoring its promise as an efficient nanosensor for AFB۱ detection and highlighting the critical role of defect engineering in graphene-based sensor design.

Keywords:

Aflatoxin B۱ , Sensor , Perfect , Single- and Double- Vacancy Defective Graphenes , Density functional theory , AIM analysis