Synthesis and characterization of copper (II) nitrate polyacrylamide & its application as opto-electronic humidity sensor

The present paper reports the effect of humidity on the transmitted power through the nanostructured copper (II) nitrate polyacrylamide (Mm) complex film at room temperature. For this purpose, the precursor of Cu(II) nitrate polyAAm was prepared and used for the deposition of a film on the substrates of borosilicate. The film was then investigated using SEM which revealed the uniform leaf-like structured morphology. By UV vis spectrophotometer, it was found that the absorption of light took place in UV region and the corresponding optical energy band-gap was observed as 4.02 eV. The diffraction pattern obtained from TEM showed the crystalline nature of the material. Powder XRD revealed the minimum crystallite size as 9 nm and average size as 13 nm which was further confirmed by the Zeta Nano-sizer. The film was employed as transmission based opto-electronic humidity sensor. Maximum sensitivity was found as similar to 0.838 mu W/%RH. Response and recovery times were found as 31 s and 76 s respectively. Experiments were repeated time to time and reproducibility was found similar to 96% with negligible ageing effect. The investigated sensor being optical in nature has the capability of multiplexing the information with the signal. (C) 2017 Elsevier B.V. All rights reserved.