Potentiometric CO2 Sensor Using Li Ion Conducting Li3PO4Thin Film Electrolyte

Whyo Noh, L. Satyanarayana, Jin Park
2005 Sensors  
Li + ion conducting Li 3 PO 4 thin film electrolytes with thickness 300nm, 650nm and 1.2µm were deposited on Al 2 O 3 substrate at room temperature by thermal evaporation method. Reference and sensing electrodes were printed on Au interfaces by conventional screen printing technique. The overall dimension of the sensor was 3 x 3 mm and of electrodes were 1 x 1.5 mm each. The fabricated solid state potentiometric CO 2 sensors of type: CO have been investigated for CO 2 sensing properties. The
more » ... properties. The electromotive force (emf) and ∆emf/dec values of the sensors are dependent on the thickness of the electrolyte film. 1.2µm thickness deposited sensor has shown good sensing behavior than the sensors with less thickness. The ∆emf values of the sensor are linearly increased up to 460 o C operating temperature and became stable above 460 o C. Between 460-500 o C temperatures region the sensor has reached an equilibrium state and the experimentally obtained ∆emf values are about 80% of the theoretically calculated values. A Nernst's slope of -61mV/decade has been obtained between 250 to 5000 ppm of CO 2 concentration at 500 o C temperature. The sensor is suitable for ease of mass production in view of its miniaturization and cost effectiveness after some further improvement.
doi:10.3390/s5110465 fatcat:cgu5issudzahjc6ycawucv6fhm