In situ growth of silver nanoparticles on polydopamine-coated chalcogenide glass tapered fiber for the highly sensitive detection of volatile organic compounds in water

A high-sensitivity Ge-Sb-Se chalcogenide glass (ChG) tapered fiber (TF) sensor based on a polydopamine (PDA)-silver nanoparticle (AgNP) coating structure is proposed for the first time in this study. The influence of PDA coating thickness on sensitivity to p-xylene aqueous solution is investigated by characterizing the immersion time of TF in the dopamine. Experimental results demonstrate that an increased coating thickness results in higher sensitivity. Based on the reduction of Ag ions by catechol groups in PDA, the optimized PDA-coated TF is exposed to the AgNO3 solution to grow in-situ AgNPs on the coating surface. The existence of AgNPs can introduce effective light coupling between the AgNPs and evanescent waves, enhancing the infrared absorption of the molecules. The sensitivity of the PDA-coated sensor functionalized by AgNPs to detect p-xylene is significantly improved to 4.115E-4 a.u./mu g/mL, which is 63 times higher than that of the uncoated sensor. Furthermore, the sensor based on the PDA-AgNP structure exhibits a shorter response time and good practical applicability.

Automated summary

This study proposes a high-sensitivity Ge-Sb-Se chalcogenide glass tapered fiber sensor coated with polydopamine-silver nanoparticles structure. The sensitivity to p-xylene is improved by increasing the thickness of the polydopamine coating. By growing in-situ silver nanoparticles on the coating surface, effective light coupling and enhanced infrared absorption are achieved. The sensitivity of the coated sensor to detect p-xylene is significantly improved, making it a promising candidate in practical applications.