Poles apart gravity based planar organic multifunctional sensor using cobalt (II) phthalocyanine

This article represents the investigations of organic multifunctional sensors. These sensors were fabricated on gravity conditions which are poles apart with the active layer of cobalt phthalocyanine (CoPc). The devices were electrically characterized for both humidity and light intensity w.r.t impedance and capacitance. CoPc was drop casted from its solution at poles apart conditions of gravity; such as positive (+1 g) and negative (-1 g) gravity. In both cases, the deposited thin layer has a thickness of around 10-15 mu m. The substrate was industrially made ceramic alumina sheet having length and width of 14mmand 7 mm with interdigitated silver electrodes. The surface morphology of the samples showed that the devices fabricated at +1 g were relatively less rough than those deposited on -1 g. Moreover, experiments showed that the devices fabricated on+ 1 g were more sensitive (-290 K Omega/% and 0.023 pF/%) in case of humidity than those fabricated at -1 g(-120K Omega/% and 0.011 pF/%). Similar behavior was also observed in case of light sensitivity; -208 K Omega cm(-2) mW(-1), 0.025 pFcm(2) mW(-1) for +1 g and -156 K Omega cm(2) mW(-1), 0.019 pFcm(2) mW(-1) in case of -1 g. Thus, results showed that both the materials and deposition technology have an impact on the active layer of the devices.