HUMIDITY AND TEMPERATURE DEPENDENT CHARACTERISTICS OF Ag/SnNcCl2/Ag SURFACE TYPE MULTIFUNCTIONAL SENSOR

In this work, the potential of tin (IV) 2,3-napthalocyanine dichloride (SnNcCl2) has been studied for sensing applications due to its hydrophobic nature. The multipurpose sensor was fabricated by depositing 50-nm silver (Ag) electrodes on a glass substrate through vacuum thermal evaporation at pressure of ∼10−5 mbar. With the help of masking, a 40-micron inter-electrode gap between Ag electrodes was developed and then 80-nm film of SnNcCl2 was thermally deposited in the inter-electrode gap resulting in a surface type Ag/SnNcCl2/Ag multipurpose sensor and was studied for humidity and temperature sensing. The humidity characterization was carried out at two different frequencies, i.e. 120 and 1kHz in the relative humidity range 35–85% RH and 5.5 and 1.3 times increase was recorded with respect to initial capacitance for both frequencies, respectively. The temperature sensing was studied within a temperature range of 15–80∘C at 120Hz frequency and 1.3 times increase in capacitance was observed with respect to initial capacitance. The sensor’s important parameters, i.e. response time and recovery time were measured to be 8 and 3s at 120Hz for humidity measurements. The morphology of the SnNcCl2 thin film was measured by atomic force microscope (AFM) and scanning electron microscope (SEM) showing rough surface favorable for sensing applications. The amorphous structure of the film was confirmed by X-ray diffraction (XRD) while optical bandgap was calculated from ultraviolet-visible (UV-vis) spectroscopy.