A highly sensitive photoelectrochemical sensor with polarity-switchable photocurrent for detection of trace hexavalent chromium

SENSORS AND ACTUATORS B-CHEMICAL

卷:317

Article

Liu, Qingyuan^1,2  Kim, Jungyoon²  Cui, Tianhong² 

[1] Tsinghua Univ, Dept Precis Instruments, State Key Lab Precis Measurement Technol & Instru, Beijing 100084, Peoples R China

[2] Univ Minnesota, Dept Mech Engn, 111 Church St SE, Minneapolis, MN 55455 USA

关键词: Photoelectrochemical sensing;    Hexavalent chromium;    Graphene;    Titanium dioxide;    Photocurrent polarity;    Charge transport;   

DOI  :  10.1016/j.snb.2020.128181

来源: Elsevier

【 摘 要 】

Signal quenching photoelectrochemical sensors have attracted extensive research interests due to outstanding performance and simplicity in realization. This work proposes a photoelectrochemical sensor with photocurrent polarity-switchable property for highly selective and sensitive detection of trace hexavalent chromium (Cr(VI)) ion. Layer-by-layer self-assembled graphene intercalation layer and drop-coated TiO2 nanocrystalline film are successively deposited onto patterned Au/SiO2/Si electrodes. By facilitating the photon-excited electron-hole pair separation, graphene significantly enhances the intensity and stability of the device photocurrent. Coupled with light-sensitive quercetin and its specific interaction with Cr(VI), such sensors can selectively switch the photocurrent polarity from anodic to cathodic with increasing Cr(VI) concentration, resulting in a large sensing range from 1.4 ppb to 2592.3 ppb, with a low detection limit of 0.44 ppb. Featured by the facile fabrication process, low-cost materials, good selectivity, and stable photocurrent output, this sensor shows promising potential applications to on-site environment monitoring.

【 授权许可】

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