Owing to the effective combination between MoS2 sheets with CuInS2 nanoparticles (NPs), a direct Z-scheme heterojunction was successfully constructed and proved as a promising structure to modify the working electrode surface with the aim of enhancing overall sensing performance towards CAP detection. Herein, MoS2 was employed as a high mobility carrier transport channel with a strong photo-response, large specific surface area, and high in-plane electron mobility, while CuInS2 acted as an efficient light absorber. This not only offered a stable nanocomposite structure but also created impressive synergistic effects of high electron conductivity, large surface area, highlight exposure interface, as well as favorable electron transfer process. Moreover, the possible mechanism and hypothesis of the transfer pathway of photo-induced electron-hole pairs on the CuInS2-MoS2/SPE as well as their impacts on the redox reaction of K3/K4 probes and CAP were proposed and investigated in detail via a series of calculated kinetic parameters, demonstrating the high practical applicability of light-assisted electrodes. Indeed, the detection concentration range of the proposed electrode was widened from 0.1 to 50 μM, compared with that of 1-50 μM without irradiation. Also, the LOD and sensitivity values were calculated to be approximately 0.06 μM and 0.4623 μA μM-1, which is better than that of 0.3 μM and 0.095 μA μM-1 without irradiation.
Keywords: Accumulation times; Adsorption capacity; Analyte molecules; Electrochemical sensors; Rate constant (k(s)).
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