Theoretical Approach for Detection of POCl3 Molecule by the Boron Nitride Nanosheet-based Sensing Nanodevices

To detect POCl3 molecule, adsorption phenomena of this molecule on the pure, Al- and Si-doped BN sheet surfaces were investigated via density functional theory (DFT) approach. The most stable adsorption complexes, including POCl3/BN (O-B), POCl3/Al-BN (O-Al), and POCl3/Si-BN (O-Si), were predicted with the adsorption energies of about -8.64, -37.01 and, -62.01 kcal mol-1, respectively. Upon the adsorption process, the computational parameters indicated that the interaction of POCl3 with Si-BN sheet was highly strong energetically, rationalizing more reactivity of the Si-BN to POCl3, which led to the dissociation of this toxic molecule into the lower toxicity fragments with less harm to environmental protection. However, very strong interactions are not propitious in the sensing performance because of the high recovery time of the sensor. Based on the density of states (DOS) analysis, it was also revealed that the electronic sensitivity of the Al-BN sheet to POCl3 increased with a significant variation by about -27.99% in the HOMO/LUMO energy gap. These changes are confirmed by the large electron charge transfer (QT) from POCl3 molecule to the sheet surface and appearance the electronic new states within the energy gap (Eg). As a result, the changes in the electronic conductivity of the sheet create an electrical signal in the electronic circuit for detecting POCl3 in the surrounding. Therefore, Al-BN possesses a more efficient function as a potential resource in the gas sensors.