Gas-sensing Properties of Photoluminescence-type Macroporous SnO2-based Sensors

Macroporous (mp-) SnO2 thick films mixed with 2.5 mol% Eu2O3 and 0~50 mol% metal oxide (mp-SnO2(mM):Eu, M: constituent metal element (Mg, Ca, Sr, Ba or Li) of metal oxide (MO) mixed, m: the content of metal oxide (mol%)) were fabricated by a modified sol-gel method employing PMMA microspheres as a template. The photoluminescence (PL) intensity of mp-SnO2(mM):Eu due to Eu 3+ ions increased with mixing MO in the thick films. These films were subjected to the PL response measurements to various gases (acetone, NO2 and O2), and their PL intensities changed clearly upon exposure to these gases balanced with air or N2. Response of PL to these gases tended to increase with an increase in their PL intensities, and the addition of 20 mol% MgO or LiO0.5 was more effective in improvig their responses among all films tested.