A Planar-Type CO₂ Sensor Using NASICON and Perovskite-Type Oxide Thin-Films

Abstract

A planar-type CO₂ sensor using NASICON and perovskite-type oxide thin-films could be prepared by novel solgel methods using aqueous complex and polymer-based precursors, respectively. NASICON thin-film could be fabricated onto alumina substates by spin-coating a tartaric acid-based gel, drying at 150°C, and sintering at 1000°C for 3h. Preparation of perovskite-type oxide thin-films at 500°C was also developed by the use of poiy (vinyl alcohol) (PVA)-acetylacetone polymer precursor. The sensor device combined with LaNiO₃ and NASICON thin-films showed high sensitivity to CO₂ at 300-400°C. The 90% response time to 1000ppm CO₂ was as short as 10-30s at 300-400°C.