Bioinspired Metal Mesh Structure with Significant Electrical and Optical Properties

Abstract

etc. Macroscopic metal grids have been successfully developed and used as a front electrode for inorganic solar cells and are a potential replacement of thin metal films as transparent electrode (TE) in organic optoelectronic devices also. [19] They exhibit high visible light transparency due to the large open area between the thick lines of metals and high conductivity due to the continuity of mesh with metal lines crossing each other and reduced junction resistance. Tuning of the work function is also possible by selecting the metal. [20] Photolithography, nanolithography, or transfer printing methods have been employed to develop metal grid electrodes, which however are complicated and tedious processes. [21,22] Metal nanowires-based 1D network shows the high merit of optical and electrical properties on becoming an excellent transparent conducting electrode, but suffer from certain limitations such as rough surface finish, poor adhesion properties, change in properties with temperature variation. The bare Ag NW suffers from oxidation and melting issues when exposed to temperature and air during device fabrication and application. The best possible solution is to cover such a structure with high refractive index n-type materials with high thermal stability. The metal oxide is a suitable candidate to combine with such nanostructures. Hybrid structures (dielectric/metal NW/dielectric, DMD) have been used to resolve these issues. [3] Here, metal governs the electrical while dielectric layer improves optical properties of the hybrid structure. [23] This conventional DMD structure possesses adequate transparency in the visible region. These DMD structures due to high transparency and sufficient conductivity show great promise for their potential use in next-generation optoelectronic and energy devices. [24] Metal mesh is preferred over nanowires/macrowires because of less contact and junction resistance. [25] There are few reports of fabrication of metal nanostructure using soft lithography [9] and leaf structure [25] for energy and optoelectronics applications. [26] However, an extensive investigation is needed to test the structural properties and stability over a wide temperature range of such structures.The present research work reports the fabrication and study of bioinspired metal grid electrode. The electrode exhibits better, 1D metal network is one of the promising alternatives of the conventional transparent conducting electrode (TCE) viz ITO/FTO. Bioinspired fabrication of junction resistance free metal grid structures is explored for their TCE applications. The leaf-based metal grid electrodes exhibit low DC resistivity (10 −5 -10 −4 Ω cm) and high optical transparency (80-90%) in the visible spectrum. The leaf vein structures are varied to obtain better optoelectronic properties. Finally, a multilayered stacked structure (SnO 2 -Ag-Au-SnO 2 ) is deposited on a poly ethyl terephthalate substrate and low-to high-temperature electrical stability is demonstrated. X-ray photoelectron spectroscopy results are...

Characteristics of High-Power Impulse Magnetron Sputtering ITO/Ag/ITO Films for Application in Transparent Micro-LED Displays

“…Notably, silver is prone to oxidation with high-temperature annealing . Therefore, scholars used the capping layer of gold to prevent such oxidation. , Our previous study analyzed Ag oxidation in an as-deposited similar ITO/Ag/ITO structure with 10 nm thick Ag. X-ray photoelectron spectroscopy spectra indicate that the Ag layer is deposited with slight oxidation and is still dominant in the metallic form .…”

Organic–Inorganic Hybrid Structure as a Conductive and Transparent Layer for Energy and Optoelectronic Applications

“…3 Several materials have been investigated as alternatives to ITO and shown good optical and electrical properties as required for a TCE. 4 These materials include metal nanowire/ mesh networks, 5 conducting organic chains, 6 metallic grids, 7 carbon nanotubes (CNTs), two-dimensional (2D) graphene, 8 and intrinsic as well as doped metal oxides. 9,10 The thin-film electrode of the nanowire network can be fabricated by an easy and scalable low-temperature technique but it lacks the long-term stability of conductivity in an ambient environment.…”

“…Several materials have been investigated as alternatives to ITO and shown good optical and electrical properties as required for a TCE . These materials include metal nanowire/mesh networks, conducting organic chains, metallic grids, carbon nanotubes (CNTs), two-dimensional (2D) graphene, and intrinsic as well as doped metal oxides. , The thin-film electrode of the nanowire network can be fabricated by an easy and scalable low-temperature technique but it lacks the long-term stability of conductivity in an ambient environment. To avoid deterioration in the conductivity of the silver nanowire network, the thin films need to be protected from the environment. , Thin metal films are also considered as an option for the transparent electrode. , There is a tradeoff between electrical conductivity and optical transmittance, which is directly dependent on the metal layer thickness.…”

Scalable Fabrication of Scratch-Proof Transparent Al/F–SnO2 Hybrid Electrodes with Unusual Thermal and Environmental Stability

“…Moreover, its changing surface properties with the exposed environment limit its usage in TCEs, and all such drawbacks remained unattended until recently. Sepat et al and Yu et al have deposited SnO 2 on bio-inspired Ag–Au mesh and Ag thin film, respectively, following the sputtering method for the deposition, which is not really advantageous. Chemical methods have not been considered seriously in this context, as the oxide precursor solutions prove to be destructive on metal networks .…”