Real-time detection of volatile organic compounds (VOCs) is being spotlighted for its importance in environmental monitoring and disease detection from the breath. However, the selective detection of VOCs in a small form factor gas sensor remains a challenge. Here, we present the VOC sensing performance of phthalocyanine (Pc)-functionalized graphene chemiresistors supported by the theoretical prediction of Pc's VOC interactions. Pc functionalization, with and without metalation, was studied parametrically with varying deposition parameters to explore impacts on the gas sensing response toward VOCs as a function of substrate coverage. Sensing data were collected to establish fingerprint signatures for a variety of VOCs. Improvement in selectivity is shown by successfully differentiating the VOCs from each other when combined into a gas sensor array tested with acetone, ethanol, formaldehyde, and toluene.

We present a comparative investigation between thin films of graphene oxide (GO) and chemically reduced graphene oxide (rGO) deposited onto glass substrates via spray pyrolysis. Two reduction techniques are investigated: (1) the exposition of a sprayed layer of GO to vapors of hydrazine hydrate to produce rGO V and (2) the addition of liquid hydrazine hydrate to a suspended GO solution, which is then sprayed onto a substrate to produce rGO L . Three different spectroscopy techniques, Raman, Fourier transform infrared, and UV–Vis–NIR, show that the two reduced samples have less lattice disorder in comparison to GO, with rGO L having the highest degree of reduction. Interestingly, topography characterization by atomic force microscopy reveals a morphological change occurring during the exposure to hydrazine hydrate vapors, resulting in a thickness of 110 nm for the rGO V film, which is a factor of 16 larger than rGO L and GO. Finally, I – V measurements show a significant decrease of the GO’s resistivity after the reduction process, where rGO L features a resistivity 90 times lower than rGO V , confirming that rGO L has the highest degree of reduction. Our results indicate that the reduction process for rGO V is susceptible to introducing intercalated water molecules in the material while the fabrication technique for rGO L is a suitable route to obtain a material with minimal lattice disorder and properties approaching those of graphene.