Dynamic Agitation‐Induced Centrifugal Purification of Nanowires Enabling Transparent Electrodes with 99.2% Transmittance

Abstract

To promote silver nanowire (AgNW) as a viable commercial alternative for transparent electrodes, it is necessary to further develop industrially scalable, high‐performance yielding and cost‐efficient methods of purifying large quantities of as‐prepared AgNW suspensions. In this work, a facile, effective, and mass scalable purification method that employs a novel dynamic agitation‐induced centrifugal filtration concept to obtain highly purified and printable AgNW solutions. This unique dynamic filtration system, which amalgamates the advantages of membrane filtration, centrifugal filtration and “cross‐flow” filtration, is effective at (1) removing nanoparticles, short nanorods and organic additives from as‐prepared AgNW suspensions without producing aggregation; (2) concentrating purified AgNW suspensions to a desirable concentration; and (3) formulating printable AgNW suspensions with suitable solvents. The resulting purified, polyol‐method synthesized AgNW with a modest aspect ratio of ≈1000 and narrowed length distribution, can be coated into flexible transparent electrodes to yield a transmittance of 99.2% and 95.2% at 230 and 29.6 ohm sq‐1 respectively. These performance metrics are comparable or exceed that of most transparent electrodes made from AgNW with larger aspect ratio (>2000) but purified through conventional purification methods. To maximize the dynamic purification efficiency, a model is also developed to describe and predict this dynamic filtration process.

Realizing Ultrahigh Mechanical Flexibility and >15% Efficiency of Flexible Organic Solar Cells via a “Welding” Flexible Transparent Electrode

“…Metal nanowires, and particularly silver nanowires (AgNWs), are considered among the most promising materials for FTEs owing to their excellent transmittance, high conductivity, and flexibility. [ 26–30 ] However, the solution‐processed AgNW network generally has a low coverage (less than 40%) and high junction resistance that would greatly deteriorate the conductivity and even the operative stability of the device as the AgNW junction locally concentrates heat by radiating under current flow. [ 9,31 ] Moreover, the randomly stacked and low‐adhesion AgNWs on the plastic substrate would likely trigger device short‐circuiting and reduce the mechanical peeling stability.…”

“…Unfortunately, when coating onto a plastic substrate, the ITO would suffer serious cracking due to shrinkage of the substrate during the thermal annealing and mechanical bending processes, thus leading to substantially increased sheet resistance and diffuse reflectance, [ 17 ] which would be harmful to the PCEs and to the mechanical stability of the flexible OSCs. To explore some promising ITO alternatives, conducting materials with high thermal annealing resistance and bending durability, such as carbon nanotubes, [ 18,19 ] graphene, [ 20,21 ] transparent conducting polymers, [ 22,23 ] metal mesh, [ 24,25 ] and metal nanowires, [ 26,27 ] have been extensively investigated. Among these, the highly conducting polymer poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PH1000) has gained significant attention due to its excellent flexibility and high conductivity.…”

High Performance Flexible Transparent Electrode via One‐Step Multifunctional Treatment for Ag Nanonetwork Composites Semi‐Embedded in Low‐Temperature‐Processed Substrate for Highly Performed Organic Photovoltaics

“…Among various flexible electrodes such as graphene, [ 16,17 ] carbon nanotube, [ 18 ] metallic nanowire, [ 19–21 ] conductive polymer [ 22 ] and their combination, [ 23–25 ] silver nanowire (AgNW)‐based electrode is one of the attractive candidates. [ 26–29 ] However, the electrodes of directly dispersed Ag nanowires on solid substrates typically show rough surface, which will deteriorate other film formations on it and cause the penetration of nanowires into adjacent films in a device structure and thus cause short‐circuit in devices. [ 27,30 ] Recently, relatively smooth morphology has been made by integrating the nanowires in polymer substrate matrix, but still with sharp peak‐to‐valley roughness of about 25 nm mainly due to the adhesion issue between the solid substrate and polymer liquid, which could cause current leakage in devices.…”

Nanowire Genome: A Magic Toolbox for 1D Nanostructures

“…With this high efficiency, 1 L of Ag NW solution containing ≈10 g Ag NWs was easily obtained (the inset of Figure f) . Furthermore, since the obtained Ag NWs are always accompanied with plenty of Ag NPs, the Liang group employed a novel dynamic agitation‐induced centrifugal filtration strategy to obtain high‐purity AgNW solutions, demonstrating a facile, effective, and mass‐scalable purification method . In addition, after application or template reaction, the Ag NWs are always oxidized to silver ions and abandoned as byproducts.…”

“…[199] Furthermore, since the obtained Ag NWs are always accompanied with plenty of Ag NPs, the Liang group employed a novel dynamic agitation-induced centrifugal filtration strategy to obtain high-purity AgNW solutions, demonstrating a facile, effective, and mass-scalable purification method. [216] In addition, after application or template reaction, the Ag NWs are always oxidized to silver ions and abandoned as byproducts. Similar to the recycling process of Te, Yu and co-workers successfully recycled Ag from the wasted byproducts with an average recovery yield of 69.8-84.6%.…”