Ti3CN MXene-based ultra-sensitive optical fiber salinity sensor

A Ti3CN MXene enabled ultra-sensitive optical fiber sensor is proposed, and a salinity measurement is conducted to evaluate its sensing performance in a low-concentration target molecule detection environment. Owing to the abundance of hydrophilic functional groups (-O, -F, and -OH), large specific surface, and broad-spectrum absorption characteristics of the MXene layers, the sensing performance of the MXene-incorporated sensor is greatly improved and an ultra-high salinity sensitivity of -5.34 nm/parts per thousand is achieved (equivalent to a refractive index sensitivity of -33429 nm/RIU). Such an excellent sensing performance is 137.33% higher than that of the bare fiber sensor and is significantly enhanced over previously reported fiber sensors. Furthermore, the sensing performance of the sensor is improved without damaging the fiber structure, which is a huge advantage when compared with the traditional fiber post-processing techniques. Finally, because the refractive index is commonly used to characterize the detection ability of biosensors, our contribution suggests the integration of MXene as a potential approach to develop high-performance optical fiber biosensors. (C) 2021 Optica Publishing Group