Real Time, Flexible RF Sputtered ZnO Nano-film CO2 Sensor for Capnographic Applications

In this research we aim to develop a real time, flexible, nano-film CO2sensor that can be fixed inside a mask for the purpose of capnography. Capnography is monitoring of the concentration or partial pressure of carbon dioxide in the respiratory gases. Its main development has been as a monitoring tool for use during anesthesia, intensive care, pulmonary perfusion, alveolar ventilation, respiratory patterns. The shape of curve is affected by some forms of lung diseases; in general, there are obstructive conditions such as bronchitis, emphysema and asthma in which the mixing of gases within the lung is affected. Currently, capnography is done using a capnography that utilizes a set of infrared trans mitter and receiver attached to a mask, which is a bit bulky setup. But in case of our sensor, we deposit interdigitated Au/Ti electrodes on a free standing nanosheet that acts as our substrate, then further depositing ZnO sensing layer on top of interdigitated part of electrodes. Measurements can be carried out by measuring the resistance between two terminals of electrodes. Due to adsorption of CO2on the sensing layer, the resistance between the electrodes will be changes resulting in a graph, which will show the curve in proportion to conc. of the CO2in air. This sensor is only 10mm X 10mm in area and few hundred nanometers thick, resulting in a sensor of almost negligible volume and weight that can be easily attached inside a mask. Sensor has a very simple fabrication and multiple pieces can be bulk fabricated at the same time under same conditions, making it very cheap and fit for commercial use. This sensor can also detect presence of few more harmful gases and vapors like acetone, ethanol and methane. So, further we have plans to make is more selective towards CO2by coating it with partially permeable membrane or by addition of some impurity.