Controllable assembly of a hierarchical multiscale architecture based on silver nanoparticle grids/nanowires for flexible organic solar cells.

In this work, an effective and facile strategy was developed to assemble a flexible hierarchical multiscale architecture by incorporating microscale silver nanoparticles (AgNPs) grids into random silver nanowires (AgNWs) networks combined with a room-temperature chemical sintering mechanism. The microscale AgNPs grids was fabricated by assemble AgNPs into a series of twin lines directly on a hydrophilic PET substrate based on coffee-ring effect with ink-jet printing technique. By regulating the assembly architecture, a flexible hierarchical multiscale conductor based on AgNPs grids/AgNWs was successfully fabricated and demonstrated a high transmittance of 87.5%, low sheet resistance of 16.5 Ω/sq and excellent mechanical flexibility. The hierarchical multiscale architecture was fairly favorable to efficiently collect free charges among the gaps in the AgNWs network, as well as to enhance the stability of conductivity by creating continuous conduction pathways. As an anode electrode in a flexible organic solar cell, the hierarchical multiscale AgNPs grids/AgNWs conductor demonstrated a more power photoelectric conversion efficiency, which was even superior to the corresponding properties of the ITO network at a similar transmittance. This simple, low-cost and nonlithographic solution-based approach would further enhance current fabrication approaches to create patterned microstructures, and have great potential to fabricate multifarious functional patterns in flexible electronic devices.