Maity Avisek, Ghosh Barnali
Department of Condensed Matter Physics and Materials Sciences, S.N. Bose National Centre for Basic Sciences, JD Block, Sec-III, Salt Lake, Kolkata, 700106, India.
Technical Research Centre (TRC), S.N. Bose National Centre for Basic Sciences, JD Block, Sec-III, Salt Lake, Kolkata, 700106, India.
Sci Rep. 2018 Nov 15;8(1):16851. doi: 10.1038/s41598-018-33365-3.
We show that a cheap, disposable type rapid paper sensor (working at room temperature) can be made using perovskite halide CHNHPbI (MAPI) to detect presence of the toxic ammonia gas (NH)by just color change, where the black colored MAPI film (on the paper) changes to yellow color in presence of a very low concentration of NH gas. The sensor can detect presence of NH gas in open or closed atmosphere down to around 10 ppm with a response time of nearly 10 sec which decreases to few seconds when the concentration exceeds 20 ppm. The easy to fabricate sensor paper being a visual sensor does not need any other extra equipment for its operation. The sensor is not sensitive to moisture with RH upto 90% and does not also respond to gases like Methane (CH), Nitrous Oxide (NO), Carbon dioxide (CO) etc in the test chamber each up to a concentration of 500 ppm. Conversion/decomposition of MAPI to PbI on exposure to NH has been proposed as the mechanism of color change and the mechanism has been established using a collection of techniques like XRD, EDX, UV-Visible absorption and Photo Luminescence.
我们展示了一种廉价的一次性快速纸质传感器（在室温下工作），它可以使用钙钛矿卤化物CH₃NH₃PbI₃（MAPI）制成，通过颜色变化来检测有毒氨气（NH₃）的存在，即纸质上黑色的MAPI薄膜在极低浓度的NH₃气体存在下会变为黄色。该传感器能够在开放或封闭环境中检测到低至约10 ppm的NH₃气体，响应时间约为10秒，当浓度超过20 ppm时响应时间会缩短至几秒。这种易于制造的传感器纸作为视觉传感器，其操作不需要任何其他额外设备。该传感器在相对湿度高达90%时对水分不敏感，在测试腔中对浓度高达500 ppm的甲烷（CH₄）、一氧化二氮（N₂O）、二氧化碳（CO₂）等气体也无响应。已提出MAPI在暴露于NH₃时转化/分解为PbI₂是颜色变化的机制，并且已使用XRD、EDX、紫外可见吸收和光致发光等一系列技术确定了该机制。
