Ultra-high resolution detection of Pb2+ Ions using a Black Phosphorus Functionalized Microfibre Coil ResonatorPhotonics Research
- Yu Yin, Shi Li, Shunbin Wang, Shijie Jia, Jing Ren, Gerald Farrell, Elfed Lewis, and Pengfei Wang
- received 03/12/2019; accepted 03/17/2019; posted 03/18/2019; Doc. ID 362167
- Abstract: A black phosphorus (BP) functionalized optical fibre sensor based on a microfibre coil resonator (MCR) for Pb2+ ions detection in an aquatic environment is presented and experimentally demonstrated. The MCR-BP sensor is manufactured by winding a tapered microfibre on a hollow rod composed of a low refractive index PC resin with the BP deposited on the internal wall of the rod. Based on the propagation properties of the MCR, the chemical interaction between the Pb2+ ions and the BP alters the refractive index of the ambient environment and thus results in a detectable shift in the transmission spectrum. The resonance wavelength moves towards longer wavelengths with an increasing concentration of Pb2+ ions and the sensor has an ultra-high detection resolution of 0.0285 ppb. The temperature dependence is 106.95 pm/oC due to the strong thermo-optic and thermal-expansion effect of the low refractive index PC resin. In addition, the sensor shows good stability over a period of 15 days. The local pH also influences the sensor, with the resonance wavelength shift increasing as pH approaches a value of 7 but then decreasing as the pH value increases further due to the effect of the BP layer by H+ and OH- ions. The sensor shows the potential for high resolution detection of Pb2+ ions in a liquid environment with the particular advantages of having a simple structure, ease of fabrication, low cost, low loss and simple interrogation.