Dual-mode detection of dopamine based on 0D/2D/2D CuInS2/ZnS quantum dot-black phosphorous nanosheet-TiO2 nanosheet nanocomposites

In this work, we designed new dual-mode turn-on electrochemical (EC) and photoelectrochemical (PEC) sensors for the detection of dopamine (DA) based on 0D/2D/2D CuInS2/ZnS quantum dot (QD)-black phosphorous nanosheet (BPNS)-TiO2 nanosheet (TiO2NS) nanocomposites. QDs can not only improve the photocurrent of the developed PEC sensors, but also provide the electrochemical signal in the EC detection. BPNSs as p-type semiconductor with high conductive properties work as electron acceptors and are utilized to improve the sensitivity of the DA PEC and EC sensors. Under irradiation of visible light or the applied voltage, DA is both excited and releases electrons, realizing turn-on detection. The PEC sensors have a linear range of 0.1-100 mu M with a lower detection limit of 0.028 mu M. For the EC detection, BPNSs can accelerate electron transfer which attribute to its excellent conductivity. In the range of 1-200 mu M, the working curve of DA detection by the EC sensors was established and the detection limit is 0.88 mu M. Comparing the two methods, the PEC sensors have a lower detection limit, and the EC sensors have a wider monitoring range. The dual-mode sensors of EC and PEC pave an effective way for the detection in biological and medical fields.

Automated summary

In this work, new dual-mode turn-on electrochemical (EC) and photoelectrochemical (PEC) sensors were designed for the detection of dopamine (DA). The sensors are based on 0D/2D/2D CuInS2/ZnS quantum dot (QD)-black phosphorous nanosheet (BPNS)-TiO2 nanosheet (TiO2NS) nanocomposites, which enable simultaneous excitation and electron release under visible light or applied voltage. The PEC sensors have a lower detection limit and the EC sensors have a wider monitoring range, providing an effective approach for detection in biological and medical fields.