Flow Synthesis of Silver Nanowires for Semitransparent Solar Cell Electrodes: A Life Cycle Perspective

Abstract

Silver nanowires (AgNWs) were prepared on a 5 g scale using either the well-known batch synthesis following the polyol method or a new flow synthesis method. The AgNWs were employed as semitransparent electrode materials in organic photovoltaics and compared to traditional printed silver electrodes based on micron sized silver flakes using life cycle analysis and environmental impact analysis methods. The life cycle analysis of AgNWs confirms that they provide an avenue to low-impact semitransparent electrodes. We find that the benefit of AgNWs in terms of embodied energy is less pronounced than generally assumed but that the toxicological and environmental benefits are significant.

Polyol Silver Nanowire Synthesis and the Outlook for a Green Process

“…The synthesis process is chemical reduction of Ag ions in the presence of a polymeric capping agent, in which a small amount of suitable salt can facilitate the growth of the silver seeds to the wire shape [9]. Several factors affect the morphology and yield of AgNWs, including reagent concentration, rate of reagent addition, preparation of the silver ion solution, capping agent molecular weight, type of salt, type and power of stirring, reactor volume in batch synthesis, and residence time in flow synthesis [59][60][61][62][63][64][65][66][67][68][69].…”

“…They utilized a 1/4-inch stainless steel tube reactor equipped with the HPLC pump for the flow synthesis of AgNW using EG, AgNO 3 , PVP, and CuCl 2 as the solvent and reducing agent, silver precursor, capping agent, and salt mediator, respectively, at temperature of 152°C. They reported flow synthesis of AgNW with lengths of 10-20 μm and thicknesses of 50-100 nm[64]. Yun et al utilized a trapped tubular flow reactor for polyol AgNW synthesis by using EG, PVP/sodium dodecyl sulfate (SDS), AgNO 3 , and NaBr as the solvent and reducing agent, capping agent, Ag precursor, and seeding agent, respectively, at temperature of 160°C.…”

Inside or Outside? Linking Outdoor and Indoor Lifetime Tests of ITO‐Free Organic Photovoltaic Devices for Greenhouse Applications

“…The replacement of the indium tin oxide (ITO) front electrode with poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) or silver nanowires (AgNWs) was demonstrated to significantly reduce both the cost and the environmental impact of the organic solar panels. This was determined considering economic simulations performed for applications of OPVs in greenhouses and life‐cycle assessments of production and use phase of OPV modules . As the electrodes are the most expensive and energy‐costing parts of the OPV, the devices using PEDOT:PSS and carbon electrodes have the cost and the cumulative energy demand (CED) of less than half of a OPV using silver electrodes .…”

“…This was determined considering economic simulations performed for applications of OPVs in greenhouses and life‐cycle assessments of production and use phase of OPV modules . As the electrodes are the most expensive and energy‐costing parts of the OPV, the devices using PEDOT:PSS and carbon electrodes have the cost and the cumulative energy demand (CED) of less than half of a OPV using silver electrodes . The environmental impact of AgNW‐based OPVs (AgNW‐OPVs) is several orders of magnitude lower than devices using ITO or silver‐grid electrodes and has the potential for intrinsically longer lifetimes .…”

“…The environmental impact of AgNW‐based OPVs (AgNW‐OPVs) is several orders of magnitude lower than devices using ITO or silver‐grid electrodes and has the potential for intrinsically longer lifetimes . Moreover, AgNW‐OPVs can achieve higher efficiencies than carbon‐based OPVs (C‐OPVs), therefore requiring less area to produce the same amount of electricity …”