Tapered Mach-Zehnder Interferometer Based On Pbs Quantum Dots Modified By Polymers For Copper Ion Sensing

An optical fiber interferometer coated with PbS quantum dots (QDs) was developed for copper ion (Cu2+) detection. The QDs were modified by a multifunctional copolymer that enabled QD surface ligation, dispersion, and coordination with Cu2+. Cu2+ coordination with the polymer induced changes in the surrounding refractive index of the interferometer. The sensor was highly selective for Cu2+ and showed a linear detection range of 0-1000 mu M with a limit of detection of 2.20 mu M in both aqueous and biological solutions. (C) 2021 Optical Society of America