Growth, characterization and sensing capabilities of 5,10,15,20-meso-tetraphenyl iron (III) porphyrin chloride films obtained by means of a novel plasma-based deposition technique

This work presents the employment a novel physical technique named glow-discharge-induced sublimation (GDS) for the production of 5,10,15,20-meso-tetraphenyl iron (III) porphyrin chloride (Fe(TPP)Cl) films. Fe(TPP)Cl films have been also deposited through spin coating (SPIN) technique, for comparison. In this paper a preliminary investigation of the physical properties and sensing capabilities of produced films are reported. The characterization of the samples has been performed through visible absorption analysis and scanning electron microscopy (SEM): visible analysis indicates the different molecular arrangements within GDS and SPIN samples and SEM images point out that GDS films are characterized by much rougher surface morphologies than SPIN ones. The sensing capabilities of the Fe(TPP)Cl samples have been investigated through optical measurements in ethyl alcohol atmospheres at different concentrations ranging from 1800 to 4500 ppm: the results highlight that GDS technique allows to produce samples characterized by up to 10 times response intensity than the SPIN ones. Moreover, GDS films show faster responses (t50 = 9 s and t90 = 43 s) and greater sensitivity than SPIN ones over the whole tested concentration range.