Triboelectric nanogenerator based on electrodeposited Ag octahedral nano-assemblies

The tremendous potential of triboelectric generators-TENGs for converting mechanical energy into electrical energy places them as one of the most promising energy harvesting technologies. In this work, the fabrication of enhanced performance TENGs using Ag octahedron nano-assemblies on ITO as electrodes significantly increases the electric charge collection of the induced tribocharges. Thereby, nanostructured electrical contacts coated with Ag macroscale nano-assemblies with octahedral features were obtained by the electrodeposition technique on flexible PET/ITO substrates. Consequently, the nanostructured triboelectric generator-TENG exhibited 65 times more maximum output power, and almost 10 times more open circuit output voltage than that of a TENG with non-nanostructured contacts passing from μW to m W capabilities, which was attributed to the increment of intrinsic interface states due to a higher effective contact area in the former. Likewise, output performances of TENGs also displayed an asymptotic behavior on the output voltage as the operating frequency of the mechanical oscillations increased, which is attributed to a decrement in the internal impedance of the device with frequency. Furthermore, it is shown that the resulting electrical output power can successfully drive low power consumption electronic devices. On that account, the present research establishes a promising platform which contributes in an original way to the development of the TENGs technology.

Sub-10nm nanogap fabrication on suspended glassy carbon nanofibers

Glassy carbon nanofibers(GCNFs)are considered promising candidates for the fabrication of nanosensors for biosensing applications.Importantly,in part due to their great stability,carbon electrodes with sub-10 nm nanogaps represent an attractive platform for probing the electrical characteristics of molecules.The fabrication of sub-10 nm nanogap electrodes in these GCNFs,which is achieved by electrically stimulating the fibers until they break,was previously found to require fibers shorter than 2µm;however,this process is generally hampered by the limitations inherent to photolithographic methods.In this work,to obtain nanogaps on the order of 10 nm without the need for sub-2µm GCNFs,we employed a fabrication strategy in which the fibers were gradually thinned down by continuously monitoring the changes in the electrical resistance of the fiber and adjusting the applied voltage accordingly.To further reduce the nanogap size,we studied the mechanism behind the thinning and eventual breakdown of the suspended GCNFs by controlling the environmental conditions and pressure during the experiment.Following this approach,which includes performing the experiments in a high-vacuum chamber after a series of carbon dioxide(CO 2)purging cycles,nanogaps on the order of 10nm were produced in suspended GCNFs 52µm in length,much longer than the~2µm GCNFs needed to produce such small gaps without the procedure employed in this work.Furthermore,the electrodes showed no apparent change in their shape or nanogap width after being stored at room temperature for approximately 6 months.