A novel signal on-off type photoelectrochemical (PEC) biosensing system was designed for sensitive detection of carcinoembryonic antigen (CEA) based on tin disulfide nanosheets loaded on reduced graphene cxide (SnS 2 -GR) as the photoactive material and gold nanoparticles coated on reduced graphene oxide-functionalized copper sulfide ( [email protected] ) for signal amplification . It's the first time for SnS 2 -GR was exploited as a sensing matrix. Here, the photocurrent signals of SnS 2 were amplified attributed to the sensitization effect of graphene. As signal amplifier, [email protected] could quench the photocurrents of SnS 2 -GR not only through the p-n type semiconductor quenching effect as well as the steric hindrance effect, but also as peroxidase mimetics to catalyze the oxidation of 4-Chloro-1-naphthol (4-CN) to produce insoluble product on the electrode surface . Based on the multiple signal amplification ability of [email protected] , CEA was detected sensitively with a linear range from 0.1 pg mL −1 to 10 ng mL −1 and limit of detection down to 59.9 fg mL −1 (S/N = 3). Meanwhile, the PEC biosensor displayed excellent performance in the assay of human serum sample, showing good application prospects for various target analysis.
Shiao Feng,Zirui Huang,Xiyu Jia,Mengjiao Dong,Chun Sun,Yonghui Zhang,Chao Fan
A SnS 2 /graphene/SnS trilayer vdW heterojunction was constructed. • Graphene promotes charge transport and suppresses dark current. • The device achieves 5656.3 A W −1 responsivity at 405 nm. • Broadband detection from 405 to 850 nm is demonstrated. • Self-powered operation and imaging applications are achieved. Two-dimensional (2D) semiconductors are promising materials for broadband photodetection, benefiting from their favorable light–matter interaction and electrical properties. As an n-type layered semiconductor, SnS 2 is suitable for photodetection because carriers can move efficiently in it and incident light can be effectively absorbed, making it suitable for photodetection applications. In this work, SnS 2 /graphene/SnS (SnS 2 /Gr/SnS) trilayer van der Waals heterojunctions and corresponding photodetectors were fabricated and investigated. Owing to the graphene interlayer, which serves as both a carrier transport layer and a barrier layer, The detector responds to light over a wide spectral range, covering both the near-ultraviolet (NUV) and near-infrared (NIR) regions. Under 405-nm irradiation, the photodetector reaches an R value of 5656.3 A·W −1 and a D ⁎ value of 3.33 × 10 13 Jones. When the wavelength is extended to 850 nm, the responsivity remains 574.2 A·W −1 . The device also shows clear self-powered behavior, outperforming the conventional SnS 2 /SnS bilayer heterojunction photodetector. These results offer an effective strategy for improving SnS 2 -based broadband photodetectors and promotes their potential applications in optical communication and single-pixel imaging. Download: Download high-res image (225KB) Download: Download full-size image
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