Thin Solid Films, Vol.630, 31-37, 2017
Silver phthalocyanine thin films carrying gold, palladium and silver nanoparticles for detection of taggants in explosives
Our work deals with thin films of silver phthalocyanine (AgPc) combined with gold, palladium and silver nanoparticles. These films were applied for the indirect detection of 2-nitrotoluene which is used as a taggant in explosives. The films were deposited by an Organic Molecular Evaporation and a DC magnetron sputtering. The growth of metallic continuously monitored through in-situ resistancemeasurements to detect the percolation threshold. We varied composition of the nanoparticles, their amount (the sputtered equivalent thickness was in the range from 1 to 50 nm) and also the geometry of sensing layers: geometry i) bottom AgPc + top nanoparticles, geometry ii) top AgPc layer + bottom nanoparticles. The sensors with geometry i) exhibited good recovery capabilities, thosewith geometry ii) seemed to better preserve phthalocyanine sensing properties. For the best combination, the AgPc(50 nm)/Au(10 nm) sensor, its dcresponse rose to the value of 373 for 190 ppmof 2-nitrotoluene. This suggests that 2-nitrotoluene can be detected in the sub-ppm concentrations by these films. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Silver phthalocyanine;Thin films;Metal;Nanoparticles;Percolation threshold;Explosive taggant;Magnetron sputtering;Gold;Palladium;Silver