Benefits, Problems, and Solutions of Silver Nanowire Transparent Conductive Electrodes in Indium Tin Oxide (ITO)-Free Flexible Solar Cells

In this review, silver nanowires (AgNWs) are introduced, as the primary material to replace indium tin oxide for fabricating cost-effective flexible organic solar cells (FOSCs), because of their remarkable solution-processing, flexibility, transparency, and conductivity, along with their enhanced properties in terms of light-scattering, plasmonic effects, and transmittance in the near infrared region. The drawbacks of AgNWs, particularly their high roughness, low adhesion to substrates, atmospheric corrosion, degradation under UV and visible light, and poor contact at wire-wire junctions, must be resolved prior to their use in commercial FOSCs applications. Herein, comparisons among all candidates (e.g., graphene, carbon nanotubes, metal grids, and conducting polymers), along with a report of all recent progress in addressing these issues for using AgNWs as flexible transparent conductive electrodes (TCEs), are discussed. In addition, recent publications on the fabrication of highly efficient FOSCs based on AgNWs are summarized. The discussed issues regarding AgNWs-TCEs apply not only to FOSCs, but can be generalized for other third-generation solar cells, such as perovskite solar cells and dye-sensitized solar cells; additionally, they provide insight for other optoelectronic applications, such as organic light-emitting diodes, liquid crystal displays, smart windows, touch panels, and heaters.