Evidence of Low-Temperature Joints in Silver Nanowire Based Transparent Conducting Layers for Solar Cells

The primary stage of joint formation of silver nanowires (AgNWs) at 60 °C is investigated by using rotary scanning transmission electron microscopy (STEM with tomographic reconstruction images) and super-large-scale molecular dynamic (MD) simulation (2 × 106 atoms). This study proves to establish that silver nanowires do not require the conventional high-temperature post-treatment process at 200 °C to form fused contacts at the intersections. In fact, a low-temperature annealing at 60 °C facilitates formation of highly conductive networks. The connection between the nanowires is made through a stage called thinning, shown in this report for the first time, which occurs before broadening of the nanowires and is caused due to simultaneous effects of loads from the top nanowires and the heating, as confirmed by STEM and MD results. The outcomes of our investigation significantly promote the application of AgNWs as a transparent conductive layer for solar cells with requirement of low-temperature processing such as kasterite, perovskite, and organic solar cells.