A DFT study of chemical sensors based on organic semiconductors (OSC) derived from 1-H-Borole

Initially, two parent molecules were designed to possess semiconductor features based on 1-H-borole. Each molecule has two active sites available to abduct ammonia molecules since both ammonia and boron behave as a Lewis acid and base, respectively. Taking the parent molecules, five derivatives were obtained using hydrogen (H), fluorine (F), methyl (Met), tert-butyl (Tert), and phenyl (Phen) groups, aiming to modulate the acidity of boron. The molecular geometries from the parent molecules and their derivatives, as well as their complexes, were optimised using the Gaussian 09 package with the B3LYP hybrid functional. The HOMO-LUMO gap was analysed, as well as the gap shift that occurs when free acid molecules abduct ammonia and create a Lewis complex, which was taken as a criterion of sensitivity. Finally, the binding energy was calculated by the counterpoise method, correcting the error due to the basis set superposition to give an insight of how feasible it is to remove the ammonia molecules from the hypothetical sensing material.