Ozone sensor made by dip coating method

We have developed an ozone sensor with an ITO (Sn-doped indium oxide) thin film made by dip-coating method. The film with 3 mol.% Sn at 360 degrees C showed excellent characteristics of ozone gas detection below 1 ppm. For in termittent exposure to ozone gas, the response time was shorter and the sen sitivity gradually increased. It was clear that the ozone sensor needed ann ealing or aging to repress the change of the sensitivity. For an applicatio n of the ozone sensor, an air purifier with the ozone sensor after aging at 20 degrees C in 60% RH for 250 h showed a good control ability of the resi dual ozone concentration, a little influence of relative humidity and ambie nt gases. It is supposed that the sensor is useful for the air purifier to be practical. (C) 1999 Elsevier Science S.A. All rights reserved.