| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2003: ¥2,600,000 (Direct Cost: ¥2,600,000)
|
|---|
| Research Abstract |
A new solid-electrolyte ion sensor device using an Na^+-ion conductor (Na_5DySi_4PO_<12>) as an impedancemetric transducer and a perovskite-type oxide thin-film as a receptor, respectively, has been developed. Cole-cole plots of the LaCoO_3/NaDyCON device in various concentration of HPO_4^<2-> at 50Hz-5MHz revealed that the imaginal part (C) or the real part (R) of the impedance was increased or decreased with increasing HPO_4^<2-> concentration, respectively. It suggests that an impedancemetric sensing of HPO_4^<2-> is possible by the use of the solid-electrolyte transducer attached with perovskite-type oxide as a receptor. The apparent response, the change of the impedance at 10 kHz on changing HPO_4^<2-> concentration of the LaCoO_3/NaDyCON device, was observed at the concentration above 1.0 x 10^<-5> M. The 90% response time from 1.0 x 10^<-3> M to 1.0 x 10^<-2> M was ca. 2 min at 30℃. The impedance response was found to be increased with increasing HPO_4^<2-> concentration between 1.0 x 10^<-5> and 1.0 x 10^<-2> M. This sensor showed a little sensitivity to NO_3 at high concentration, while no response was observed to the examined ions of Cl^-, ClO_4, and H_2O_2. Sensing performance to hydrogen-phosphate ion of the various sensor elements using some perovskite-type oxides were further investigated. The elements with LaBO_3(B=Cr,Fe) systems were unstable in the sensing condition and thus showed poor response characteristics. The devices with La-Co systems were found to show rather highest sensing performance at the frequency of 10kHz, on the other hand, the devices with LaBO_3(B=Fe,Mn) systems also showed high sensitivity at the higher frequency of 100Hz. The partials substitution of A' of Ca,Sr,Ba,and Ce in La_<0.8>A'<0.2>CoO_3 systems not gave the improvement of the sensing performance. The sensing mechanism of this new type of ion sensor device is under investigation.
|
