CO gas opto-electronic sensor using semiconductor graphene nanoribbons: A first-principles study

We have investigated physisorption of CO gas molecules on armchair graphene nanoribbons (5‐AGNRs) using first principles methods. The adsorption geometries, adsorption energies, and transferred charge are obtained. To take the van der Waals forces into account, the Grimme correction has been added to the calculation method. The transmission and optical spectrum and current–voltage (I–V) characteristic of the nanoribbons are calculated as a function of CO concentration for sensing features. We have found that the electronic and transport properties of the AGNR are sensitive to the CO physisorption, and the current through the nanoribbons increases by increasing CO density at the same bias voltage. Our results point out that CO physisorption does not have any effect on the optical properties of the pristine AGNR, however, it can extremely suppress the optical spectra of nitrogen‐doped AGNR. The nitrogen‐doped AGNR becomes more transparent by adding CO molecules. Also, the HSE06 hybrid functional has been used to improve the optical properties such as the optical gap. The transport and optical features indicate that CO molecules can be detected by GNR‐based sensors.