High sensitivity NH₃ gas sensor with electrical readout made on paper with perovskite halide as sensor material

In this paper we report a cheap, paper electronics based solid state gas sensor to detect NH₃ gas selectively with a detection capability of better than 1 ppm. The sensor uses perovskite halide CH₃NH₃PbI₃ (MAPI) as the active sensor material grown on a paper. This paper based sensor works at room temperature. The current through the paper sensor increases by one order on exposure to only 10 ppm NH₃ gas. The calibrated sensitivity is ~55% for 1 ppm of NH₃ gas in Nitrogen or Air. The current noise limited resolution estimated to be ~10 ppb. This work establishes perovskite halide as a new solid state gas sensing material that can reach sub ppm sensitivity using simple paper electronics. Use of paper and also solution method used to grow the active material makes the sensor cost effective and easy to manufacture. This type of disposable high sensitive paper sensor can be used for detection of NH₃ as a marker in exhaled breathes for non-invasive diagnosis. The sensor formed on the paper, since it supports unheated operation, needs less than few nanowatt power for its operation.