Asymmetric contacts were used to assemble extremely photosensitive and self-powered photodetectors (SPDs) on rigid and polyimide (PI) substrates based on one-dimensional (1D)-CdS nanobelts. The photoresponse characteristics of the constructed devices were outstanding, including high photosensitivity (1.54 × 10⁶%), specific detectivity (2.36 × 10¹² Jones), responsivity (36 mA W⁻¹) and noise equivalent power (2.94 × 10⁻¹⁵ W Hz^−1/2) with 215 μW cm⁻² light irradiation, as well as having high reproducibility, environmental stability and speedy response of less than 30 ms. Flexible self-powered photodetectors (FSPDs) were also constructed on PI substrates, which had comparable photoresponse performance to the rigid one. Additionally, the as-fabricated FSPDs showed excellent folding endurance, electrical and mechanical flexural stability. Our findings suggest that the asymmetric contact device design used in this study is appropriate for high-performance FSPDs, particularly ultrafast nanodevices.

In this paper, K-doped δ-MnO₂ nanoflowers decorated with Au nanoparticles (MnO₂–Au) were synthesized by a hydrothermal method. To probe the effect of the band gaps in the MnO₂ support over the surface plasmon resonance (SPR)-mediated catalytic conversions on Au nanoparticles (NPs), the oxidation of p-aminothiophenol (PATP) to p,p′-dimercaptoazobenzene (DMAB) was used as a model reaction. We found that the PATP conversion was significantly higher for the MnO₂–Au hybrid compared with its individual Au NPs under excitation at 633 nm. Furthermore, the activities of the MnO₂–Au materials increased as the MnO₂ support displayed higher K-doped levels, which led to narrower band gaps. These results could be explained based on the transfer of photogenerated electrons from MnO₂ to Au, increasing the electron density in Au NPs and thus contributing to improved SPR-mediated activity. In this case, our observations show that tuning the band gaps can have a significant impact on SPR-mediated conversions, in which narrower band gaps should facilitate the charge transfer of SPR-excited charge carriers and thus lead to better performances. Our findings presented may provide important insights into the role of the support materials in plasmonic catalysis, indicating that, in addition to the control over several physical and chemical parameters (such as shape, surface area, defects, among others), the proper tuning of the band gap can serve as an effective strategy for the optimization of activities.

A nanoscale core–shell NiO@CoO composite is prepared on flexible carbon cloth for electrodes in supercapacitors and overall water splitting. The needle-like CoO nanowires with NiO nanosheets as the active materials improve the elemental constituents as well as surface area. The NiO@CoO electrode boasts a capacity of 2.87 F cm⁻² (1024.05 F g⁻¹) at 1 A g⁻¹ current density, and even at a large current density of 20 A g⁻¹ the retention ratio is 80.9% after 5000 cycles. The excellent specific capacity with high rate capability can be ascribed to the unique structure which increases the area of the liquid–solid interface and facilitates electron and ion transport, improving the utilization efficiency of active materials. The asymmetric hybrid supercapacitor prepared with the core–shell electrode shows the energy output of 40.3 W h kg⁻¹ at 750 W kg⁻¹ with a better retention (71.7%) of specific capacitance after 15 000 cycles. In addition, linear sweep voltammetry is performed to assess the performance of the electrode in water splitting and the electrode shows excellent activity in the OER as manifested by a Tafel slope of 88.04 mV dec⁻¹. Our results show that the bifunctional structure and design strategy have large potential in energy applications.