Enhanced polymeric guided-mode resonance sensor for volatile organic compound gas detector

The optical characteristics of polymers are improved by adding tungsten and titanium oxides, which are projected to raise the refraction value, offering greater resonance and sensing capacity to VOC vapor.The sensor was fabricated in a single step using a combination of spin coating and drop casting. The sensor properties were then characterized using FE-SEM, Ellipsometry, and an Interferometer. The sensing was tested using 2-propanol, Ethanol, Ammonia, Formaldehyde, and Water.The EDS energy mapping confirmed the presence of WO3 and TiO2 in the sample. The ellipsometry showed that the refractive index was enhanced from 1.50 to 1.53 and 1.54 by WO3 and TiO2 embedding, respectively. The resonance location at 566 nm for neat polymer and 576 nm for polymer composite confirms that the resonance was guided accordingly as simulated by RCWA. Using a polymer composite as a waveguide increases the vapor detection of formaldehyde and ammonia by 35%, reaching 0.98 nm and 1.18 nm of resonance shift, respectively.