Chemical bonding and tunable adsorption of volatile formaldehyde on B and N decorated antimonene: first-principles insights

In this work, using first-principles calculations, we explored the sensing properties of formaldehyde (CH₂O) on pristine antimonene (p-Sb), single vacancy modified antimonene (SV-Sb), and triple X-doped (X = B, N) SV-Sb (SV-3X-Sb). It is found that CH₂O is physically adsorbed on p-Sb with adsorption energy E_a of -0.11 eV. The E_a slightly increased in SV-Sb (-0.17 eV). The maximum E_a was observed for SV-3B-Sb and SV-3N-Sb with E_a of -0.81 (-0.86) eV, respectively. Because of moderate adsorption strength, the electronic and magnetic properties of SV-Sb and SV-3X-Sb are slightly altered in the presence of CH₂O. The SV-Sb with CH₂O exhibits half-metallic character. The direct band gap (E_g) of SV-3B-Sb is slightly increased after adsorption, and in the presence of CH₂O the semiconducting SV-3N-Sb showed a metallic character. These changes in electronic properties are attributed to charge transfer from absorbent to CH₂O. These findings suggest that the sensitivity of antimonene for CH₂O detection can be tuned with defects.