Highly sensitive and selective room temperature NH3 gas microsensor using an ionic conductor (CuBr) film

A new ammonia gas microsensor was developed, based on the large resistance change of an ionic conductor (CuBr) film when exposed to low NH₃ concentrations. The detection is based on specific interactions between ammonia molecules contained in the gas atmosphere and mobile copper ions in the copper(I) bromide layer. The sensor is operating at ambient temperature and allows highly sensitive and specific ammonia detection. The sensor works at ammonia concentrations between 1 and 500 ppm. There are no significant cross-effects to acetylene and carbon monoxide and only a weak cross-sensitivity to hydrogen sulfide gas (200 ppm). The selectivity was experimentally compared with commercial tin dioxide sensors (TGS 826). The sensor fabrication is a simple process, allowing low cost device production.