Nanomesh Electrodes Research Articles

Asymmetry in supramolecular assembly.

Photoresponsive organic nanowires connect to gold nanomesh and silicon electrodes

Nanomesh electrode on MgZnO-based metal-semiconductor-metal ultraviolet photodetectors.

In this work, the nano-scaled mesh electrodes are fabricated by obliquely depositing metals through the highly ordered polystyrene nanosphere mask. Furthermore, the intrinsic MgZnO film is deposited as the absorption layer for the metal-semiconductor-metal ultraviolet photodetectors (MSM-UV-PDs) using the vapor cooling condensation system. The 100-nm-linewidth nanomesh electrodes with metal occupying a roughly 10% of the device surface region consequently render PDs with a high transmittance in the ultraviolet (UV) wavelength range. The photoresponsivity of MgZnO-based MSM-UV-PDs evaluated at the wavelength of 330 nm with the operating bias voltage of 5 V is elevated from 0.135 to 0.248 A/W when the thin metal electrode is replaced by the nanomesh electrode, and the corresponding quantum efficiency is improved from 50.75 to 93.23%. Finally, adopting the nanomesh electrode also helps to enhance the UV-visible rejection ratio (R330nm/R450nm) and the detectivity from 1663 and 1.78 × 1010 cmHz0.5W−1 to 2480 and 2.43 × 1010 cmHz0.5W−1, respectively.

OLEDs: Enhanced Light Extraction from Mechanically Flexible, Nanostructured Organic Light‐Emitting Diodes with Plasmonic Nanomesh Electrodes (Advanced Optical Materials 9/2015)

OLEDs: Enhanced Light Extraction from Mechanically Flexible, Nanostructured Organic Light‐Emitting Diodes with Plasmonic Nanomesh Electrodes (Advanced Optical Materials 9/2015)

Enhanced Light Extraction from Mechanically Flexible, Nanostructured Organic Light‐Emitting Diodes with Plasmonic Nanomesh Electrodes

Characteristics of light extraction from nanostructured organic light‐emitting diodes (OLEDs) incorporating plasmonic metal nanomesh anodes are investigated for achieving high‐performance, flexible OLEDs. Given that flexibility of devices is limited by rigid and fragile constituents such as indium tin oxide electrodes, alternative transparent, and flexible electrodes including nanomesh‐type metal films have been widely studied, where high transparency, low resistance, and good flexiblity were regarded as essential requirements of high‐performance flexible applications due to the expectation that they are closely related to the device performance. However, here it is reported that a metal nanomesh optimized for high transmittance cannot promise high device efficiency when it is used as an anode of OLEDs. Systematic experiments together with analytic simulations elucidate that the surface plasmon loss is singnificantly reduced by metallic cathode nanostructures that were inherently formed from a periodic nanomesh anode, which results in huge enhancement of the light extraction, though the optimal period of the nanomesh anode for high light extraction is inconsistent with that for high transmittance. Further performance characterization of nanostructured OLEDs with metal nanomesh anodes provides insight into strategies to realize highly efficient flexible OLEDs.

Highly stretchable and transparent nanomesh electrodes made by grain boundary lithography

Foldable photoelectronics and muscle-like transducers require highly stretchable and transparent electrical conductors. Some conducting oxides are transparent, but not stretchable. Carbon nanotube films, graphene sheets and metal-nanowire meshes can be both stretchable and transparent, but their electrical resistances increase steeply with strain <100%. Here we present highly stretchable and transparent Au nanomesh electrodes on elastomers made by grain boundary lithography. The change in sheet resistance of Au nanomeshes is modest with a one-time strain of ~160% (from ~21 Ω per square to ~67 Ω per square), or after 1,000 cycles at a strain of 50%. The good stretchability lies in two aspects: the stretched nanomesh undergoes instability and deflects out-of-plane, while the substrate stabilizes the rupture of Au wires, forming distributed slits. Larger ratio of mesh-size to wire-width also leads to better stretchability. The highly stretchable and transparent Au nanomesh electrodes are promising for applications in foldable photoelectronics and muscle-like transducers.

Electrical resistivity of transparent metal nanomesh electrodes

AbstractA metal nanomesh electrode has the potential to realize a low‐resistive, rare‐metal‐free transparent electrode. However, the electrical resistivity has not been measured as yet. We fabricated metal nanomesh electrodes and their electrical resistivity was obtained by measuring the current–voltage characteristics. Comparing with the calculated values of the microapertures, the electrical resistivity of the nanomesh electrode tended to deviate from the calculated values with reduction of the aperture interval and increase of the aperture density. This deviation was considered to be the effect of narrowing the conduction path of electrons and increasing the electron scattering probability by the nanoapertures. The order of the resistivity of the nanomesh electrodes was 10−6–10−5 Ω cm, one order of magnitude lower than that of conventional transparent oxides such as indium tin oxide.

Metallic nanomesh electrodes with controllable optical properties for organic solar cells

We have fabricated a metallic nanomesh using nanosphere lithography and metal evaporation. The metallic nanomesh has a precisely controlled nanostructure showing excellent uniformity with hexagonally arrayed periodic circular holes. A P3HT:PCBM organic solar cell, with the gold nanomesh electrode, demonstrates a high fill factor of 61% and a considerable power conversion efficiency of 3.12%. Electromagnetic simulation indicates that the optical properties of the metallic nanomesh can be optimized for organic photovoltaic devices by tuning the film thickness, hole diameter, and periodicity. These results show the promising potential of using a metallic nanomesh as the transparent electrode in organic solar cells.