S-vacancies mediated piezo-phototronic effect for high-performance self-powered photoelectrochemical sensing based on CdS nanorod array/ Ce-metal-organic framework heterojunction

A self-powered photoelectrochemical (PEC) sensing platform was constructed for sensitive detection of tetra-cycline (TC) based on sulfur-vacancy engineered CdS nanorod arrays/Ce-metal-organic frameworks hetero-junction (CdS NRs/Ce-MOF) with piezo-phototronic effect. CdS nanorod arrays were used as the piezoelectric generating unit and S-vacancy was introduced to coordinate the piezoelectric polarization, which could generate piezo-potential to inhibit the recombination of the electrons and holes. Moreover, the introduction of Ce-MOF could broaden the photoabsorption region, and facilitated the transfer of electrons because of the construction of the heterojunction. Due to the combination of defect engineering, piezo-phototronic effect and hetero-structure, the photocurrent of the as-fabricated CdS NR/Ce-MOF heterojunction was enhanced by 4.3-fold than that of bare CdS NR. Hence, a sensitive sensing system based on the CdS NRs and Ce-MOF was established for TC detection with the assistance of aptamer. The results showed that the sensing signal was linear with the negative logarithm of the target TC concentration in the range of 1 x 10-14 -1 x 10-8 M, and the detection limit was 1.47 x 10-15 M. Moreover, the sensor had a good anti-interference ability and stability. Such work provides inspi-ration for future work on monitoring pollutants in the environment.