Sol-Gel Synthesis of Perovskite-Type Oxide ThinFilm Using Metal Organic Acid and Its Application to Amperometric Hydrogen-Phosphate Ion Sensor

摘要

The synthesis of La-based perovskite-type oxide (LaBO_3: B = V, Mn, Fe, Co, Ni) thin-films by a sol-gel method using metal organic acids, and their amperometric sensing properties for hydrogen-phosphate ions were investigated. La-based perovskite-type oxide thin-films could be easily synthesized at 600-700℃ on Au-coated alumina substrates. Particularly, the LaCoO_3 thin-film prepared at 700℃ showed good amperometric responses to HPO_4~(2-) at a concentration between 1.0x10~(-6) and 1.0x10~(-2)M with a sensitivity of 20 mA·cm~(-2)M~(-1), when the applied potential was +1.0 V vs. SCE at 30℃. The 90% response time of the sensor device was as short as approximately 3 min, and showed a high selectivity to HPO_4~2 among the examined anions of NO_3~-, Cl~- and SCN~-.