In this study, we investigated the interaction of A-234 molecule with the pristine, Si, Ge, Sc doped and aminated C20 fullerene using density functional theory (DFT). Adsorption of A-234 molecule on pristine C20 fullerene provides insufficient adsorption energy (-5.27 kcal.mol−1) which makes it unsuitable sensor platform for detection of this molecule. When A-234 molecule is adsorbed on Si, Ge and Sc doped fullerene, the work function (Φ) alters properly (-18.78%, −25.69% and −70.43%, respectively). However, adsorption energies are very high (-104.16, −96.19 and −76.05 kcal.mol−1, respectively). In contrast, when a A-234 molecule is adsorbed from its PO head on the C20HNH2 (aminated) fullerene, its work function is considerably decreased (−12.20%) demonstrating a appropriate sensitivity and the adsorption energy (−13.55 kcal.mol−1) is small enough to provide short recovery time. In addition, the electron emission greatly increases which can be converted to an electronic noise and thus, C20HNH2 fullerene is a work function-type sensor for sensing and detection of A-234 nerve agent.