An Aqueous Ammonia Sensor Based on Printed Indium Tin Oxide Layer

Abstract

We proposed an indium tin oxide (ITO) sensor for detecting NH 3 in seawater and carried out a series of experiments to investigate the feasibility of using it as a hazardous and noxious substance (HNS) sensor. The ITO layer revealed a distinct resistance change, which was linearly correlated with the NH 3 concentration at room temperature. The ITO layer was evaluated using a seawater and ammonium hydroxide (NH 4 OH) solution. The evaluation revealed an almost linear output signal up to an NH 3 concentration of 5%. The sensitivity of the sensor showed a small temperature dependence within a 5-35 °C range. In addition, no significant degradation was observed during a 7-d-long durability test. The aqueous ammonia sensor based on a printed, porous ITO layer has been explained in terms of reduction reaction at the surface and the formation of an electrical double layer (EDL).

Performance Improvement of Indium Tin Oxide Electrochemical Sensor by Mixing Carbon Black

“…(14) Films using ITO nanoparticles showed a higher chemical stability in water than those using other metal oxides. (15) Moreover, a recent result confirmed the capability of an ITO sensor to detect ethanol concentrations as low as 619 ppb. (12) However, according to existing research, the measurement time was tens of minutes or more and needed improvement.…”

Tuning the Sheet Resistance, Ferromagnetism, and H2O2 Sensitivity of ITO Film by Introducing Tunable Pores

“…3 Chang et al found that the porous structure of the screen-printed ITO layer is preferred for developing a highly sensitive ammonia sensor. 4 Yadav et al prepared the PITO films using a sol−gel spincoating method for the CO 2 gas sensor. The porous morphology was suggested to provide many sites to adsorb CO 2 molecules and improve the sensitivity.…”

“…Due to the high electrical conductivity, transparency, and thermal stability, tin-doped In 2 O 3 (ITO) films have been widely used in information displays, electroluminescent devices, electrochromic devices, sensors, , solar cells, bioanalytical devices, , catalysis, etc. ITO incorporated with magnetism can also be used to make new magneto-optoelectronic devices. , The introduction of well-defined pores in ITO under retention of high conductivity and transparency brings the following advantages.…”

“…Watanabe et al prepared the electrochromic-dye-modified porous electrodes by spin-coating ITO nanoparticles and found that the pore size of ITO films is one of the key factors controlling the electrochromic response speed . Chang et al found that the porous structure of the screen-printed ITO layer is preferred for developing a highly sensitive ammonia sensor . Yadav et al prepared the PITO films using a sol–gel spin-coating method for the CO 2 gas sensor.…”