Self-Powered Photoelectrochemical Biosensor Based on CdS/RGO/ZnO Nanowire Array Heterostructure

Abstract

A CdS/reduced graphene oxide (RGO)/ZnO nanowire array (NWAs) heterostructure is designed, which exhibits enhanced photoelectrochemical (PEC) activity compared to pure ZnO, RGO/ZnO, and CdS/ZnO. The enhancement can be attributed to the synergistic effect of the high electron mobility of ordered 1D ZnO NWAs, extended visible-light absorption of CdS nanocrystals, and the formed type II band alignment between them. Moreover, the incorporation of RGO further promotes the charge carrier separation and transfer process due to its excellent charge collection and shuttling characteristics. Subsequently, the CdS/RGO/ZnO heterostructure is successfully utilized for the PEC bioanalysis of glutathione at 0 V (vs Ag/AgCl). The self-powered device demonstrates satisfactory sensing performance with rapid response, a wide detection range from 0.05 mm to 1 mm, an acceptable detection limit of 10 μm, as well as certain selectivity, reproducibility, and stability. Therefore, the CdS/RGO/ZnO heterostructure has opened up a promising channel for the development of PEC biosensors.

Design and tailoring of patterned ZnO nanostructures for energy conversion applications

“…PEC cells have two key processes: light trapping and the separation and transport of photogenerated carriers [120,121]. In order to improve the light-harvesting capability, highly ordered square-patterned ZnO NAs were used as the PEC photoanode [122][123][124]. For no-patterned ZnO NAs, the substrate was di- …”

Designing CdS/Se heterojunction as high-performance self-powered UV-visible broadband photodetector

“…The heterojunction photodiode not only exhibits ultralow dark current but also possesses a distinct broadband photoresponse at zero bias. On-off ratio as high as 1.1 × 10 4 , short response/decay time (2 µs/22 ms), and high responsivity (40 mA/W at 500 nm) and detectivity (1.3 × 10 13 Jones at 500 nm) are achieved for this device. These superior parameters for the device without an external bias voltage are attributed to the good contact and strong built-in electric field at the CdS/Se interface.…”

“…11,12 As a typical II-VI semiconductor, cadmium sulfide (CdS) with a narrow and direct bandgap of 2.4 eV has been considered as an ideal building block for constructing highly efficient electronic and optoelectronic devices. 13,14 For example, Li et al fabricated a single CdS nanobelt based photodetector with Ohmic contact. Compared with dark current, the photocurrent (∼30 µA) under 490 nm visible light illumination increased by a factor of 6 at a bias voltage of 1 V. 15 In spite of the large signal-to-noise ratio, a constant-voltage bias is required for the photoconductor.…”

“…This allows the device to function well at zero bias without an external bias source. The device exhibits a broadband photoresponse range of 300-700 nm, fast response speed (rise time 2 µs and fall time 22 ms) at zero bias voltage with the maximum peak responsivity of 40 mA/W and detectivity of 1.3 × 10 13 Jones at 500 nm. These critical parameters are comparable and even better than previously reported CdS or Se based self-powered photodetectors (Table I).…”

Realization of Efficient Field Emitter Based on Reduced Graphene Oxide‐Bi2S3 Heterostructures

“…To enhance and/or tune the desired property(ies) of the pristine nanostructures, one of the attempts used deal with the formation of their heterostructures with different inorganic nanomaterials/nanostructures. In this context, synthesis and characterization of rGO‐based heterostructures have been extensively explored for their potential applications in various fields, including supercapacitors, photocatalysts, biosensors, Li‐ion battery, and solar cell . Such heterostructures, owing to unique morphology and modulation of electronic properties at the interface, offer unprecedented advantages over the pristine nanostructures …”