Lossy mode resonance based 1-butanol sensor in the mid-infrared region

The utilization of nanometric Graphene Oxide / Polyethyleneimine (GO/PEI) bilayers deposited onto SnO2-coated CaF2 planar waveguides significantly enhances the sensitivity of Lossy Mode Resonances (LMR) based devices for gas sensing applications. LMR generation in the mid-infrared region, which also contributed to achieve better sensitivities, was accomplished with the aid of fluorinated (CaF2) planar waveguides. LMR wavelength shift was studied as a function of the number of GO/PEI bilayers. In the particular case of 10 bilayers of GO/PEI, the sensitivity of the device to 1-butanol was 70.4 pm/ppm, which increased by a factor of 5 compared to the device without GO/PEI bilayers. The GO/PEI sensor was also sensitive to other alcohols, like 2-propanol, but it showed negligible sensitivity to other gases, such as CO2, NH3 or C2H2. The cross sensitivity with temperature was tested at temperatures of 20, 100 and 180 ºC during water vapor measurement (1723 ppm), showing that the sensor performance was not affected by the temperature fluctuations.