Agnws

The investigated NWN were synthesized starting from Ag NWs (Sigma-Aldrich, prod. no. 739448) of length $20\mathrm{\mu }\text{m}$ to $50\mathrm{\mu }\text{m}$ , diameter $115\pm (15)\text{nm}$ , coated with 1–2 nm of PVP^{24 (link)} and concentration 0.5 wt.% in isopropyl alcohol (IPA). By the dilution of the original suspension by additional IPA we obtained NWN of AMD in the range between $70{\text{mgm}}^{-2}$ and $120{\text{mgm}}^{-2}$ (calculated). NWs were dispersed on a square quartz substrate of size $1\times 1{\text{cm}}^2$ . A detailed structural and chemical characterisation of these nanostructures is reported in our previous work^{23 (link)}.

GO solution was purchased from Graphenea Inc., San Sebastián, Spain. The GO was dispersed in deionized (DI) water with a 4-mg/mL concentration. The GO was diluted using isopropanol (IPA) and then coated on an optical grade PET substrate (Nan Ya Plastics, BH215, New Taipei City, Taiwan) via spin-coating with 1000-rpm spin speed for 30 s to form GO sheets. Hereafter, these prepared samples are labeled “GO/PET.” Subsequently, the GO/PET was baked to remove the solvent thoroughly using a hot plate at 60 °C for 10 min. The thickness of as-prepared GO film was about 30 nm measured by atomic force microscope. The details were described in Supplementary Materials Figure S1. In addition, AgNWs were purchased from Sigma-Aldrich, Saint Louis, MO, USA (average diameter: 35 μm; length: 115 μm). The AgNWs were dispersed in IPA with a 0.5 wt % concentration. Before being coated onto PET substrate via drop casting, which was followed by drying at 60 °C for 30 min, the AgNWs were also diluted in IPA at various concentrations. This AgNW/IPA solution was then coated on the PET followed by the GO coating under the same conditions as those used for the GO/PET samples. The prepared samples, hereafter, are referred to as GO/AgNWs/PETs.

The patterned membranes were exposed to O2-plasma (100 W, 4 min) and soaked in DI water containing detergent (Triton X100, Sigma Aldrich). AgNWs (60 nm diameter, 10 μ m long, Sigma Aldrich) were dispersed in ethanol, vortexed and briefly ultrasonicated. Immediately prior to filtration, the AgNWs were diluted in 15 ml DI water and vortexed. The dispersion was filtered through the membrane and the membrane with the deposited AgNWs was dried on a hotplate (50 °C, 10 min). The surface coverage of AgNWs on the patterned membrane area was approximately 0.17 mg/cm².

PH1000 (Clevios), which is a mixture of PEDOT:PSS (1:2.5 by weight) in aqueous solution, was used as the conducting solution for the anode. PH1000 had a solid content of 1.0–1.3%, a viscosity of 15–50 mPa·s, and a conductivity of ~850 S/cm. To increase the conductivity, PH1000 and 5 wt% DMSO (99.9% ACS reagent, Sigma-Aldrich) were mixed and stirred for 24 h. The conducting solution for the cathode consisted of 0.5 wt% Ag NWs (Sigma-Aldrich) in IPA. The average diameter and length of the Ag NWs were ~60 nm and ~10 μm, respectively.