Facile fabrication of portable electrospun poly(vinyl alcohol)/sulfur quantum dots film sensor for sensitive and selective detection of Fe3+

Here, a portable nanofibrous composite film sensor based on biocompatible poly(vinyl alcohol) (PVA) and fluorescent sulfur quantum dots (SQDs) was prepared by electrospinning method. To endow the PVA/SQDs film sensor with high structural stability, glutaraldehyde was employed as cross-linking agent to react with PVA and SQDs. Thanks to the stabilization of PVA, the PVA/SQDs film showed strong and stable solid-state fluorescence, which overcomes the disadvantage that dried SQDs powder cannot emit fluorescence due to aggregation induced fluorescence quenching effect. In addition, the porous structure of PVA/SQDs film enables it to retain the sensitive fluorescence response ability of SQDs to Fe3+. The PVA/SQDs film exhibited sensitive and selective fluorescence quenching behavior towards Fe3+. The fluorescence intensity of PVA/SQDs film presented good linear relationship with the concentration of Fe3+ in the range of 0–0.53 mM. The detection limit could reach 0.69 μM, which can well meet the detection demand of Fe3+ in drinking water. Additionally, using PVA/SQDs as a portable sensor to detect Fe3+ in real water sample was examined with satisfactory performance. Considering the simple preparation process and good sensing performance of PVA/SQDs, this paper opens up a new opportunity for using SQDs as a solid sensor to detect metal ions.