Ultrasensitive photoelectrochemical sensing platform based on heterostructural CuO/NCDs@Au nanocomposites with the efficient photo-induced carrier separation

Abstract

Heterogeneous composite is considered a valuable material to boost the photo-electrochemical (PEC) properties. Herein, the porous hollow and thin-shell CuO particles were prepared by calcining a Cu-BTC precursor. N-doped carbon dots (NCDs) as both reductor and stabilizer can reduce the Au+ to gain regularly nanoflower NCDs@Au, which further to create type-Ⅱ heterogeneous interface of CuO/NCDs@Au. PEC monitoring results showed that the CuO/NCDs@Au nanocomposite displayed markedly improved photocurrent response than the monocomponent CuO or CuO/NCDs. This outstanding photoelectric property was ascribed to the multiple reflection/scattering effects from the porous hollow structure of CuO particles which led to more photo-induced e−/h+ pairs. The obtained heterostructured CuO/NCDs@Au could magnify synergistically the photocurrent output signal. Ab (antibodies) was accurately immobilized on the CuO/NCDs@Au modified ITO electrode via a facility amidation reaction. Fabricated Ab/CuO/NCDs@Au/ITO PEC sensing platform for AFP (alpha-fetoprotein) detection manifested an enhanced sensitivity (3.32 × 10-4 ng mL−1) with wide linear range (0.001 ∼ 300 ng mL−1), which was superior compared to the electrochemical results. This works developed an excellent heterojunction nanocomposite of CuO/NCDs@Au, which provided well-synthesized strategies for structuring high-performance photocatalysts based on MOFs derivant.