CuO/Ag₂S/CuS Nanohybrids-Integrated Photoelectric and Photothermal Effects for Ultrasensitive Detection of Inorganic Pyrophosphatase

Promotion of the photoelectric (PE) response is of great importance for improving performances of solar cells, photocatalysis and photoelectrochemical (PEC) sensing. Herein, advanced CuO/Ag₂S/CuS nanohybrids (NHs) are developed in which the CuO/Ag₂S NHs have superior PE properties while the CuS nanoparticles own notable photothermal (PT) feature. Under illumination of 850 nm light, the CuO/Ag₂S NHs are in-situ heated by the PT effect of CuS, which significantly facilitates carrier generation and migration, thus eventually increasing related PE response by 1.4 times with a PT contribution percentage of 34.3% to the total photocurrent. Based on this PT-promoted PE mechanism together with an enzymatic catalysis-induced Cu species regulation, a bio-friendly PEC sensing platform is established, realizing the sensitive determination of inorganic pyrophosphatase with a broad detection range from 0.05 to 35 mU ml⁻¹ and a low detection limit of 0.02 mU ml⁻¹. In particular, further variable temperature tests show that this PT effect is even capable of shrinking the band gap of CuS (from ≈2.1 to ≈1.3 eV), expanding the wavelength range of adoptable excitation light, thereby being beneficial for biological applications. In comparison with other methods, promotion of PE response with PT effect has few restrictions on photoactive materials, and is therefore valuable to various PE-relevant applications.