Adsorption of phenol, hydrazine and thiophene on stanene monolayers: A computational investigation

The adsorption of phenol, hydrazine and thiophene molecules on the stanene monolayers were investigated using the density functional theory calculations. Various adsorption positions of molecules on the stanene monolayers were tested. The properties of the adsorption systems were investigated in terms of adsorption distance, adsorption energy, band structures, molecular orbitals, charge density difference (CDD) and projected density of states (PDOS). Adsorption energy results indicate that the adsorption of phenol, hydrazine and thiophene molecules on the stanene is energetically favorable. Phenol and thiophene molecules show a weak physisorption on the stanene monolayers due to the lack of covalent bond at the interface region, whereas hydrazine exhibits chemisorption on the stanene sheet. The adsorption of phenol, hydrazine and thiophene molecules induces a narrow band gap at the Fermi level of stanene, leading to the semiconductor property of the combined system (stanene + adsorbate). The adsorption of hydrazine on the surface makes a more significant change on the electronic properties of stanene than that of phenol and thiophene. The large PDOS overlaps between the PDOS spectra of the tin and nitrogen atoms indicate the formation of chemical bonds between these atoms. The charge density difference calculations represent charge accumulation on the adsorbed molecules.