Design of Planar Type CO2 Sensor for Indoor Enviroment Measurement

紧凑型CO2传感器在各种环境下对CO2的监测和控制有着很大的需求。在目前提出的各种类型的CO2传感器中，固体电解质与辅助相金属碳酸盐相结合的电位型传感器因其良好的传感性能而特别吸引人。然而，从实用的角度来看，这些设备在结构上仍然是原型。在本研究中，我们试图利用NASICON厚膜设计平面型CO_2传感器，以降低制造成本和减小传感器的尺寸。(1)采用溶胶凝胶法制备了NaSICON(Na_3Zr_2Si_2PO_2；12)粉末，并添加了α-松油醇。在氧化铝衬底上丝网印刷30μm厚的浆料。在950和1000℃下焙烧后，厚膜中NASICON的形成基本完成，但膜的致密性仍然较差。所得到的平面器件在干燥条件下可以很好地作为二氧化碳传感器工作，但不能在全…下工作试图通过添加玻璃形成组分来提高NASICON厚膜的密度和机械强度。这种器件的电动势不仅在干燥空气中表现出对CO2的良好响应，而且在潮湿空气中也表现出良好的响应，尽管Nernstian关联式的斜率比理论值略小。(3)NASICON厚膜的致密化被探索用于平面CO2传感器。在用于丝网印刷法的纳西康粉末的多种分散剂中，乙二醇经1000℃焙烧后显示出最致密的纳西康厚膜。所得到的平面器件在潮湿和干燥条件下都表现出了良好的CO2传感性能。(4)为了减小湿度的干扰，考察了BiCuVOx氧化物离子导体作为对电极材料的适用性。氧化物掺杂的器件在干燥和潮湿条件下都具有稳定的CO2传感特性。此外，加入氧化物的器件可以显著降低电动势对相对湿度的依赖。较少

A compact C0_2 sensor has been in a great demand for monitoring or controlling C0_2 in various environments. Among the various types of C0_2 sensors so far proposed, the potentiometric type combining a solid electrolyte with an auxiliary phase of metal carbonate is particularly attractive from its excellent sensing capability. From a practical point of view, however, the devices still remain prototype in structure. In this study, we tried to design planar type C0_2 sensor using NASICON thick film for the lower fabrication cost and down sizing of sensor devices.(1) NASICON (Na_3Zr_2Si_2PO_<12>) powder was prepared by a sol-gel method and was added with α-terpineol. The resulting paste was screen-printed 30μm thick on the alumina substrate. NASICON formation in thick film was almost complete after calcination at 950 and 1000℃, although film densification was still poor. The resulting Planar device could work fairly well as a C0_2 sensor under dry conditions but was unable to work at all … More under humid condition.(2) It was attempted to improve the density and mechanical strength of NASICON thick film with addition of glass forming components. The EMF of the resulting device exhibited excellent response to C0_2 not only in dry but in humid air, although the slope of the Nernstian correlations tended to be slightly less steep than the theoretical one.(3) Densification of thick film of NASICON was explored for the use in a planar C0_2 sensor. Among the many kinds of dispersants of NASICON powder for screen printing method, ethylene glycol was found to exhibit the best densified NASICON thick film after calcination at 1000℃. The resulting planar device showed good C0_2 sensing properties under humid as well as dry conditions.(4) In order to reduce the disturbance by humidity, applicability of an oxide ionic conductor of BiCuVOx as a counter electrode material was examined. The oxide-incorporated devices exhibited stable C0_2 sensing properties under dry as well as humid conditions. In addition, the dependence of EMF on relative humidity could be reduced considerably with the oxide-incorporated devices. Less