Heejeong Shin1 Hyosung Choi1

1, Chemistry, Hanyang University, Seoul, Seong-dong-gu, Korea (the Republic of)

A solution-processed transparent conducting electrode was fabricated via layer-by-layer (LBL) deposition of graphene oxide (GO) and silver nanowires (Ag NWs). First, graphite was oxidized with a modified Hummer’s method to obtain negatively-charged GO sheets, and Ag NWs were functionalized with cysteamine hydrochloride to acquire positively-charged silver nanowires. Oppositely-charged GO and Ag NWs were then sequentially coated on a 3-aminopropyltriethoxysilane modified glass substrate via LBL deposition, which provided highly controllable thin films in terms of optical transmittance and sheet resistance. Next, the reduction of GO sheets was performed to improve the electrical conductivity of the multilayer films. The resulting GO/Ag NWs multilayer was characterized by a UV-Vis spectrometer, field emission scanning electron microscope, optical microscope and sheet resistance using a four-point probe method. The best result was achieved with a 2-bilayer film, resulting in a sheet resistance of 6.5 Ω sq-1 with an optical transmittance of 78.5% at 550 nm,which values are comparable to those of commercial ITO electrodes. The device based on a 2-bilayer hybrid film exhibited the highest device efficiency of 1.30% among the devices with different number of graphene/Ag NW LBL depositions.
Ag NWs films exhibited low sheet resistance and high optical transmittance, which are comparable to those of commercial ITO electrode. We fabricated an organic photovoltaic device based on Ag NWs as the anode/V2O5 as the HTL/P3HT:PCBM/Al, and optimized device with Ag NWs exhibited power conversion efficiency of 1.30% and 1.72%.