Phthalocyanine/graphene hybrid-materials for gas sensing in bio-medical applications

In this work the fabrication of graphene/metal phthalocyanine (MePc) hybrid-materials was investigated. MePcs are biomimetic compounds modelled after the biologically important class of porphyrins (e.g. heme-group). They are widely used in sensing applications, since they exhibit easily detectable physicochemical changes when exposed to analytes frequently found in biology such as alcohols, aldehydes and other hydrocarbons, which makes them potential candidates for bio-medical devices such as breath-analyzers. Hence, it was attempted to enhance sensing performance by introducing graphene, which offers intriguing new possibilities for MePc-based sensing materials. Hybrid-material has been produced by mixing and sonicating graphene and MePc in solution. This method lead to immobilization of MePc on graphene sheets by π-π stacking. The material has been investigated by UV/Vis spectroscopy, optical-and electron scanning microscopy (SEM). Finally, gas sensing experiments have been performed to investigate the influence of the addition of graphene on the optical and electrical sensing behaviour of MePc films. It could be shown that the effect on optical sensing capabilities is rather slight. However, upon introduction of highly conductive graphene, MePc-based materials are more readily applicable as conductometric/potentiometric gas sensors.