Hirokazu Tachibana

Ozone sensor made by dip coating method

Abstract 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°C showed excellent characteristics of ozone gas detection below 1 ppm. For intermittent exposure to ozone gas, the response time was shorter and the sensitivity gradually increased. It was clear that the ozone sensor needed annealing or aging to repress the change of the sensitivity. For an application of the ozone sensor, an air purifier with the ozone sensor after aging at 20°C in 60% RH for 250 h showed a good control ability of the residual ozone concentration, a little influence of relative humidity and ambient gases. It is supposed that the sensor is useful for the air purifier to be practical.

Sensor for detecting the stoichiometric composition in a combustion flame

Abstract The performance of Sr 0.65 La 0.35 Co 0.7 Fe 0.3 O 3−δ as a sensor, as well as it calatytic activity, are studied in relation to additions of SrTiO 3 and the further addition of Pd. The temperature dependence of the sensor with more than 40 mol% SrTiO 3 at temperature below 400°C is semiconductor like and does not rely on the gas atmosphere, which allows us to use the material as a temperature sensor ( e.g )., a flame detector). Gas sensitivity occurs at temperature above 400°C and the addition of 60 to 70 mol% SrTiO 3 gives the highest sensitivity, response and catalytic activity. The working temperature can be lowered by about 100°C by the further addition of Pd. Additions of SrTiO 3 and Pd also improve the lifetime of the device.