Volatile Organic Compounds sensing properties of TbPc2 thin films: Towards a plasmon-enhanced opto-chemical sensor

A sublimated film of double decker terbium(III) bis(phthalocyaninato) complex (TbPc2) has been tested for optical gas sensing applications. Morphological characterization of the sensing layer has been performed by atomic force microscopy. TbPc2 has been used as an opto-chemically interacting material to detect a class of volatile organic compounds (VOCs) following in real-time the UV–vis optical absorption variation. The interaction mechanism taking place between the investigated analytes and this double-decker-based thin films has been evaluated through the Freundlich isotherm. Additionally gold nanostructured plasmonic transducers grown onto glass substrate have been used as alternative functional substrate: the excitation of surface plasmon resonances at frequencies close to those of the bis-phthalocyanine molecular resonances has been investigated as a possible factor for increasing the sensing performances towards the investigated VOCs. By monitoring the shift of the typical localized surface plasmon resonance (LSPR) peak a plasmon-enhanced functionality is added and investigated thoroughly.