Black Phosphorus All-Fiber Sensor for Highly Responsive Humidity Detection

Black phosphorus (BP) promises high-performance humidity sensing, due to its unique electrical, mechanical, and surface properties. Different from traditional transistor-based BP humidity sensors, herein, an all-fiber sensing strategy is proposed by integrating BP nanosheets with etched single-mode fiber (ESMF). The experiments show that transmitted light in the ESMF can be effectively modulated by the coated BP nanosheets as relative humidity varies from 35% to 80%. Due to the combination of unique sensing characteristics of BP materials with a high sensitivity of optical modulation strategy, highly responsive humidity sensing is achieved with the response time as fast as 7 ms. This work demonstrates a BP-based all-optical sensing platform not only for high-performance humidity sensing, but also for opening up new opportunities for many potential vapor/gas sensing applications in the fields of biomedicine and chemistry.