Synthesis and Characterization of Silver Nanowires as a transparent and flexible electrode for Application in Polymer Solar Cells

Today, application of silver nanowires (AgNWs) as flexible and transparent conductive electrodes extremely was attracted as an alternative to ITO electrodes in polymer solar cells (PSCs). In current work, synthesis and controlling dimension ratio of the silver nanowires were investigated. Firstly, AgNWs were synthesized by polyol method. The effect of presence of sodium chloride seed were evaluated as a key factor in the formation of silver nanowires. Also the effect of Poly Vinyl Pyrrolidone (PVP) to the silver precursor ratio was investigated as controlling agent of AgNWs aspect ratio. Formation of AgNWs and their aspect ratio were evaluated by Ultraviolet-Visible (UV-Vis) spectroscopy and Scanning Electron Microscopy (SEM), respectively. The results showed that at the low ratio of PVP/AgNO3, obtained AgNWs, showed less diameter and longer length in comparison to high ration of PVP/AgNO3. Using of Fourier transform infrared spectroscopy (FT-IR) technique, confirmed polymer removing from the surface of silver, during the process of washing and purification. In order to provide flexible and transparent conductive electrode of AgNWs, these nanowires were deposited on a flexible substrate of polyethylene terephthalate (PET) by spin coating technique. Optical and electrical properties of designed electrodes such as surface resistance and transmittance percent were measured using resistivity measurment and UV-Vis spectroscopy in wavelength 550 nm, respectively. Different volume of AgNW solution was applied to construction the flexible electrode. The best electrode as an alternative to ITO was obtained with 44.47% transmittance and surface resistance of 2.75 Ω/cm2.