Ultrasensitive carbon monoxide sensor based on asilver grating coated by single layer of palladiumchloride at room temperature

We introduce a sensitive carbon monoxide(CO) sensor based on alayer of palladium chloride dihydrate PdCl2 · 2H2O (PCD) which can work atroom temperature. The core part of the sensor is a plasmonic grating coatedwith PCD. When the CO molecules hit on PCD which will change into palladium (Pd), the reflectivity of the grating will change a lot. First-principlescalculations and finite-difference time-domain methods are employed to calculate the dielectric constant of PCD and the reflection spectra, respectively. Ourresults show that The maximum difference of the reflection spectra betweenbefore and after reactions (∆R = RPCD - RPd) reaches to 20% times as themaximum of the reflection spectrum in certain conditions. According to ourcalculations, CO can be easily detected, when the concentration of CO is aslow as 2.2×10-3ppm. Our proposed structure is quite useful and has potentialapplications in safety productions, food safeties and other fields