Department of Mechanical Engineering, Chungbuk National University , Cheongju, 361-763, South Korea.
ACS Nano. 2015 Oct 27;9(10):9898-905. doi: 10.1021/acsnano.5b03325. Epub 2015 Sep 30.
Black phosphorus (BP) atomic layers are known to undergo chemical degradation in humid air. Yet in more robust configurations such as films, composites, and embedded structures, BP can potentially be utilized in a large number of practical applications. In this study, we explored the sensing characteristics of BP films and observed an ultrasensitive and selective response toward humid air with a trace-level detection capability and a very minor drift over time. Our experiments show that the drain current of the BP sensor increases by ∼4 orders of magnitude as the relative humidity (RH) varies from 10% to 85%, which ranks it among the highest ever reported values for humidity detection. The mechanistic studies indicate that the operation principle of the BP film sensors is based on the modulation in the leakage ionic current caused by autoionization of water molecules and ionic solvation of the phosphorus oxoacids produced on moist BP surfaces. Our stability tests reveal that the response of the BP film sensors remains nearly unchanged after prolonged exposures (up to 3 months) to ambient conditions. This study opens up the route for utilizing BP stacked films in many potential applications such as energy generation/storage systems, electrocatalysis, and chemical/biosensing.
黑磷（BP）原子层在潮湿空气中会发生化学降解。然而，在更坚固的配置中，如薄膜、复合材料和嵌入式结构，BP 有可能在大量实际应用中得到利用。在这项研究中，我们探索了 BP 薄膜的传感特性，并观察到其对潮湿空气具有超灵敏和选择性的响应，具有痕量检测能力和随时间的微小漂移。我们的实验表明，随着相对湿度（RH）从 10%变化到 85%，BP 传感器的漏电流增加了约 4 个数量级，这在湿度检测中是前所未有的。机理研究表明，BP 薄膜传感器的工作原理基于水分子自电离和在潮湿 BP 表面生成的磷氧酸的离子溶剂化引起的泄漏离子电流的调制。我们的稳定性测试表明，BP 薄膜传感器的响应在长时间（长达 3 个月）暴露于环境条件下几乎保持不变。这项研究为利用 BP 堆叠薄膜开辟了道路，可应用于能源产生/存储系统、电催化和化学/生物传感等许多潜在应用。
