Ru-Doped PtTe2 Monolayer as a Promising Exhaled Breath Sensor for Early Diagnosis of Lung Cancer: A First-Principles Study

Using the first-principles theory, the geometric and electronic properties of the Ru-doped PtTe2 (Ru-PtTe2) monolayer, and its sensing performance for three VOCs biomarkers, namely, 2-propenal (C3H4O), acetone (C3H6O) and isoprene (C5H8), were analyzed, to expound its potential for exhaled breath analysis and diagnosis of lung cancer. It was found that the Ru-substitution on the surface of the pristine PtTe2 surface with a Te atom is energy-favorable, with the formation energy of -1.22 eV. Upon adsorption of the three VOC gas species, chemisorption was identified with the adsorption energies of -1.72, -1.12 and -1.80 eV for C3H4O, C3H6O and C5H8, respectively. The Ru-doping results in a strong magnetic property for the PtTe2 monolayer, whereas the gas adsorption eliminates this magnetic behavior. The electronic properties reveal the sensing mechanism of the Ru-PtTe2 monolayer for gas detection, and the bandgap change indicates its admirable positive sensing response for the three gas species. Therefore, we conclude that the Ru-PtTe2 monolayer is a promising sensing material to realize the diagnosis of lung cancer through exhaled gas detection, with a remarkable decrease in its electrical conductivity. This work paves the way for further exploration of the PtTe2-based gas sensor for early diagnosis of lung cancer, and we hope that more sensing materials can be investigated using the PtTe2 monolayer.