A significant enhancement of photoresponse from the light-controlled conductive switching based on Cu2O/rGO nanocomposites was experimentally demonstrated. Cu2O/rGO nanocomposites were synthesized via a facile wet-reduced method. The crystalline structure, morphologies, and photoluminescence of the Cu2O/rGO nanocomposites were characterized and analyzed. The fabricated conductive switching was measured under the irradiation of a continuous laser. When the laser was turned on and off alternately, the photoconductive switching obviously displayed a state conversion between “on” and “off” reversibly. Furthermore, the typical current–voltage (I–V) and current–time (I–t) curves exhibited a relatively high switching ratio (Ion/Ioff) of 3.25 and a fast response time of 0.45 s. The excellent “on–off” characteristics of the device show promising applications in memory storage and logic circuits.

Enhanced performance of light-controlled conductive switching in hybrid cuprous oxide/reduced graphene oxide (Cu 2 O/rGO) nanocomposites

This review focuses on introducing and explaining electrodepostion mechanisms and electrodeposition-based synthesis strategies used for the production of catalysts and semiconductor electrodes for use in water-splitting photoelectrochemical cells (PECs). It is composed of three main sections: electrochemical synthesis of hydrogen evolution catalysts, oxygen evolution catalysts, and semiconductor electrodes. The semiconductor section is divided into two parts: photoanodes and photocathodes. Photoanodes include n-type semiconductor electrodes that can perform water oxidation to O2 using photogenerated holes, while photocathodes include p-type semiconductor electrodes that can reduce water to H2 using photoexcited electrons. For each material type, deposition mechanisms were reviewed first followed by a brief discussion on its properties relevant to electrochemical and photoelectrochemical water splitting. Electrodeposition or electrochemical synthesis is an ideal method to produce individual components and ...

Electrochemical Synthesis of Photoelectrodes and Catalysts for Use in Solar Water Splitting

Hybrid Cu2O-based heterogeneous nanostructures possess novel synergistic properties that arise from the integrated interaction between the disparate components, thereby showing promising potential for various important applications including solar cells, carbon monoxide oxidation, photocatalysts, field emission, sensors, templates and so on. With the rapid progress in nanomaterials science and nanotechnology, hybrid Cu2O-based heterogeneous nanostructures with well-controlled compositions, shapes and sizes have been rationally designed and synthesized. This review attempts to summarize the important advances in the development of different types of hybrid Cu2O-based heterogeneous nanostructures, such as hybrid Cu2O–metal nanostructures, hybrid Cu2O–metal oxide nanostructures and hybrid Cu2O–carbon nanostructures. The correlations between the improved performances and interfacial structures of the hybrid Cu2O-based heterogeneous nanostructures are discussed based on some important and representative examples. Several key scientific issues and perspective research directions in this field are also given.

Recent advances in hybrid Cu2O-based heterogeneous nanostructures

Synthesis of copper sulfide nanowire arrays for high-performance supercapacitors

Zinc oxide (ZnO) has been considered as one of the potential materials in solar cell applications, owing to its relatively high conductivity, electron mobility, stability against photo-corrosion and availability at low-cost. Different structures of ZnO materials have been engineered at the nanoscale, and then applied on the conducting substrate as a photoanode. On the other hand, the ZnO nanomaterials directly grown on the substrate have been attractive due to their unique electron pathways, which suppress the influence of surface states typically found in the former case. Herein, we review the recent progress of ZnO nanostructured materials in emerging solar cell applications, such as sensitized and heterojunction architectures, including those embedded with promising perovskite materials. The remarkable advancement in each solar cell architecture is highlighted towards achieving high power conversion efficiency and operational stability. We also discuss the foremost bottleneck for further improvements and the future outlook for large-scale practical applications.

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ZnO nanostructured materials for emerging solar cell applications

Template synthesis of copper oxide nanowires for photoelectrochemical hydrogen generation

Heterostructural p-Cu2O/n-ZnO solar cells are fabricated by the consecutive electrochemical deposition of an n-ZnO nanorod layer, followed by a p-Cu2O layer on a transparent conductive substrate. The growth parameters, growth temperature and time of applied potential, which determine the crystalline structure and film thickness of Cu2O, are fine-tuned to investigate their effects on the performance of heterojunction solar cells. From XRD and SEM analyses, the best crystalline quality and the optimum Cu2O film thickness are accomplished at the potential of −0.4 V and the growth temperature of 60 °C for 10 min. In addition, the electrolyte concentration plays an important role in the optical absorbance of Cu2O film, which significantly exhibits two-time enhancement as adjusting the CuSO4 concentration of 0.4 M to 0.02 M. The best performance of the heterojunction cell is able to achieve the conversion efficiency of 0.33% with Voc, Jsc, and FF being 0.15 V, 7.03 mA cm−2, and 0.33, respectively. Hence, this study demonstrates that the proposed strategy to improve the solar cell performance realized by electrochemical deposition has the potential to produce cheap and environmentally friendly solar cells.

Hung-Hsun Lin

Papers

Template synthesis of copper oxide nanowires for photoelectrochemical hydrogen generation

Electrochemical growth and characterization of a p-Cu2O thin film on n-ZnO nanorods for solar cell application

Polarity-dependant Performance of p-Cu2O/n-ZnO Heterojunction Solar Cells