Ultrasensitive and Recyclable Upconversion‐Fluorescence Fibrous Indicator Paper with Plasmonic Nanostructures for Single Droplet Detection

• Published in: Advanced optical materials 2019-10, Vol.7 (19), p.n/a
• Main Authors: Li, Xin, Zhang, Jun, Zhang, Jun‐Cheng, Wang, Xiao‐Xiong, Liu, Jiang‐Jun, Li, Ru, Yu, Miao, Ramakrishna, Seeram, Long, Yun‐Ze
• Format: Article
• Language: English
• Subjects: Droplets; electrospun nanofibers; fluorescence sensors; Fluorescent indicators; Food additives; Hydrophobicity; Materials science; Nanorods; Nanostructure; Optics; plasmonic nanostructures; Recyclability; Rhodamine; Target detection; Upconversion; upconversion fluorescence
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.201900364

Conventional indicator paper is disposable after use and requires a large amount of target solution. Herein, recyclable upconversion fluorescence indicator papers consisting of upconversion nanorods and plasmonic nanostructures are fabricated by electrospinning. This recyclable indicator paper exhibits good flexibility and superhydrophobicity with enhanced upconversion fluorescence. Rhodamine B (RhB) is selected as the target solution because it is prohibited as a food additive but often occurs in food, and conventional detection methods usually need a large volume of solution (>1 mL) to refine to higher concentrations because of the low detection sensitivity. Significantly different from the traditional detection system, this upconversion fluorescence fibrous indicator paper can detect RhB as low as 0.01 ppm, which is superior to most reported detection limits for fluorescence sensors. Moreover, this indicator paper can detect a single droplet (≈10 µL) of RhB without needing a large amount of solution. After detection, the target solution is easily removed for excellent recyclability, which is another advantage over the traditional detection system. Fibrous indicator paper with upconversion fluorescence is fabricated by electrospinning. These indicator papers exhibit good flexibility and superhydrophobicity with enhanced fluorescence, and they are used as ultrasensitive and recyclable upconversion‐fluorescence sensor for single droplet detection. The detection limit of this sensor can reach as low as 0.01 ppm for RhB.