Facile and Efficient Welding of Silver Nanowires Based on UVA‐Induced Nanoscale Photothermal Process for Roll‐to‐Roll Manufacturing of High‐Performance Transparent Conducting Films

Abstract

The continuous, large-area solution-processed production of silver nanowire (AgNW) transparent conducting films with outstanding optoelectronic and mechanical performance remains a challenge. Here, efficient welding of AgNWs is demonstrated using ultraviolet A (UVA) with the specific wavelength range from ≈320 to ≈400 nm based on a nanoscale photothermal process. The AgNW welding shows a self-terminating and self-limiting nature, and sensitivity to diameter of AgNWs. Sheet resistance of the UVA-illuminated (UVAI) AgNW films rapidly drops within 2 min without loss of transmittance. For the UVAI AgNW (30 nm in diameter) film, decrement of sheet resistance approaches three orders of magnitude (≈10 5 -10 2 Ohm sq −1 ) with original transmittance being (97%) retained, which significantly enhances its optoelectronic properties. Enhanced mechanical flexibility, electromagnetic interference (EMI) shielding effectiveness (SE), and heating performance are obtained in the UVAI AgNW films. The SE and plateau temperature of the AgNW film increase to 25 dB and 50 °C after illumination, respectively. Smart window, transparent heater, and triboelectric nanogenerator based on the UVAI AgNW film demonstrate its versatile applications in optoelectronics. Finally, the welding method is easily integrated into a roll-to-roll process to manufacture AgNW film with a low sheet resistance of 25 Ohm sq −1 and a high transmittance of 90%, and excellent flexibility.

Metal‐Based Flexible Transparent Electrodes: Challenges and Recent Advances

“…[86,90] Post-treatment is another effective approach to reducing the contact resistance of metal nanowire networks. Effective posttreatment methods include supersonic spaying, [91,92] mechanical pressing, [84,92,93] cold isostatic pressing, [94] plasmonic welding, [95][96][97] capillary-force-induced cold welding, [98][99][100] solvent-induced welding, [100] electron beam irradiation, [101] thermal annealing, [102,103] light-induced welding, [104][105][106][107][108] electroplating welding, [109][110][111][112] and electroless welding. [113] In general, these post-treatments eliminate the solvent residues and enhance the contact at junctions, so as to improve the electrical conductivity of metal nanowire networks while maintaining the optical transmittance.…”

“…Reproduced with permission. [107] Copyright 2018, Wiley-VCH. b) Schematic and structure of graphene and metal nanowire hybrid films produced by a continuous roll-to-roll process.…”

“…The post-treated AgNW films showed a low sheet resistance (25 Ω sq −1 ), a high optical transmittance (90%), and outstanding flexibility. [107] Deng et al demonstrated fully encapsulated graphene/AgNW FTEs fabricated by a continuous large-area R2R process (Figure 5b). The encapsulated FTEs exhibited remarkable corrosion resistance and excellent mechanical flexibility while maintaining high electrical and optical performance (sheet resistance of ≈8 Ω sq −1 at 94% transmittance).…”

“…a)Schematic illustration of roll-to-roll coating of silver nanowire network via slot die, with the integration of post-treatment (UVA illuminating). Reproduced with permission [107]. Copyright 2018, Wiley-VCH.…”

Femtosecond Laser Patterning Wettability‐Assisted PDMS for Fabrication of Flexible Silver Nanowires Electrodes

“…[4][5][6][7] Among these materials, silver nanowires (AgNWs) have great application prospects due to their compatibility with a solutionprocess, excellent photo electric performance, and mechanical toughness. [8][9][10][11] For prac tical application of AgNWs, the precise patterning of AgNWs is Some surface treatment combined with mask assisting method, such as thermally grown SiO 2 /Si wafer, oxygen plasma, or ultraviolet ozone treatment can create hydrophilic functional groups on substrate surface to realize the coating of conductive ink. [28,35,36,38] For example, Chou et al [28] fabricated micronscale AgNWs patterns with a width of 30 µm based on polydimethylsiloxane (PDMS) substrate using a parylene stencil mask.…”