六价铬
光电流
铬
电极
光电子学
材料科学
光活性层
石墨烯
图层(电子)
化学
纳米技术
能量转换效率
冶金
聚合物太阳能电池
物理化学
作者
Yukui Zhang,Jungyoon Kim,Tianhong Cui
标识
DOI:10.1016/j.snb.2020.128181
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.
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