Delivered by Publishing Technology to: S. Rajaratnam School of International Studies, NTU IP: 155.69.4.4 On: Thu, 27 Feb 2014 17:37:38 Copyright: American Scientific Publishers Copyright © 2014 American Scientific Publishers All rights reserved Printed in the United States of America Nanoscience and Nanotechnology Letters Vol. 6, 216–220, 2014 Deposition of ZnO-Valinomycin Film on Al Substrate for the Detection of K + in KOH Solution Priyabrata Pattanaik 1 , Sushanta Kumar Kamilla 1 , Jyoshnarani Mohapatra 2 , Bikash Kumar Jena 3 , Debi Prasad Das 3 , and Dilip Kumar Mishra 2 ∗ 1 Semiconductors Research Laboratory, Institute of Technical Education and Research, Siksha ‘O’ Anusandhan University, Bhubaneswar, Odisha 751030, India 2 Department of Physics, Institute of Technical Education and Research, Siksha ‘O’ Anusandhan University, Bhubaneswar, Odisha 751030, India 3 CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha 751013, India Chemically synthesized Nanocrystalline ZnO with valinomycin was deposited on Al substrate by modified chemically wet and dry (CWD) method. The lattice parameters a and c of ZnO are esti- mated to be 3.258 Å and 5.183 Å with an average crystallite size of 60 nm. The micrograph and energy dispersive X-ray spectrum analysis clearly indicates that ZnO is embedded in the valino- mycin fibres. The ohmic character and non-magnetic character of the films is confirmed from the electrical and frequency dependent inductance characterisation. It is found that at higher frequency, impedance of the film does not depend upon the resistance and inductance. Hence the capacitance behaviour of the film is improved. The potassium sensing ability of the ZnO embedded valinomycin has a life time of 20 days which predicts that this organic polymer embedded ZnO can be used as aK + detect biosensor. Keywords: Sol–Gel, Chemical Wet-Dry Method, Ohmic Character, Scanning Electron Microscopy, Biosensor. 1. INTRODUCTION Zinc oxide is an inorganic compound, widely used as an additive into numerous materials and products including polymer plastics, ceramics, glass, cement, rubber (e.g., car tyres), lubricants, paints, ointments, adhesives, sealants, pigments, foods (source of Zn nutrient), batteries, ferrites and fire retardants etc. due to its potential application in field of spintronics, optoelectronics, power sources and biosensors. 1–8 There is a growing interest in the fabrication and characterization of nanocrystalline zinc oxide coating with various additives on different substrate materials via different techniques. 3 4 ZnO has several favorable proper- ties such as direct and wide bandgap (3.37 eV at room temperature) with hexagonal (wurtzite) crystal structure, large excitation binding energy (60 MeV), resistivity con- trol over the range 10 -3 to 10 -5 Ohm cm, transparency in the visible range, high electron chemical stability, absence of toxicity and abundant in nature. 5 The conductivity also changes under photo reduction/oxidation condition. Due to these changes ZnO is suitable for different applications ∗ Author to whom correspondence should be addressed. such as chemical sensors, hetero junction solar cells, electro photography, surface acoustic wave devices, con- ductive transparent conductors and many others. However, for bio application ZnO is accounted as an important mate- rial as it is a non toxic and it enhances the efficiency of the product when used as an additive. It is well known from the literature 9 that the biosens- ing capability is enhanced many more times when ZnO is used as an additive with valinomycin for the sensibil- ity of K + . Valinomycin is an organic polymer which is mostly used in the field of biology to detect the potas- sium content in the blood of human beings. However the detection percentage is very low. Hence it is necessary to choose a biocompatibility additive which can enhance the potassium detection limit. To enhance the detection limit of potassium in valinomycin, 10 in the present work, the non-toxicity, biosafety and excellent biological com- patibility ZnO has been used with valinomycin for the deposition of films on Al substrate by sol–gel modified chemically wet and dry coating technique. The structural and microstructural characterizations have been carried out for nanocrystalline ZnO and ZnO with valinomycin 216 Nanosci. Nanotechnol. Lett. 2014, Vol. 6, No. 3 1941-4900/2014/6/216/005 doi:10.1166/nnl.2014.1740