Density Functional Theory Investigation on The Interaction of Formaldehyde with Zn Doped (6,0) SWCNT for Sensor Applications

In order to evaluate the sensor capability of Zn-atom doped single-walled carbon nanotube for the detection of formaldehyde molecule, studies were carried out using Density Functional Theory method with wB97XD/6-311G(d,p) level. In this study, Highest Occupied Molecular Orbital Energy, Lowest Unoccupied Molecular Orbital Energy and energy gap were evaluated. Adsorption energy, adsorption enthalpy and Gibbs free energy of adsorption were found. The results showed that formaldehyde interacted with Zn-atom doped single-walled carbon nanotube exothermically and spontaneously. The upward shift of HOMO and LUMO levels due to the interaction suggests that charge transfer occurs from formaldehyde to the carbon nanotube surface. The shifts in vibrational frequency and intensity provide evidence that Zn-atom doped single-walled carbon nanotube can serve as effective optical sensors for formaldehyde.