Embedment of nano-sized Ag layer into Ag-doped In2O3 films for use as highly transparent and conductive anode in organic solar cells

Abstract

By inserting a nano-sized Ag layer between bottom Ag-doped In2O3 (AIO) and a top AIO layer, we were able to control the sheet resistance and optical transmittance of AIO films for application in organic solar cells (OSCs) as a transparent electrode. To optimize the AIO/Ag/AIO multilayer, we investigated the electrical, optical, structural and morphological properties of the AIO/AgIAIO multilayer as a function of Ag interlayer thickness with a constant bottom and top AIO thickness of 35 nm. The optimized AIO/AgIAIO multilayer showed a much lower resistivity of 3.988 x 10(-5) Omega cm and a higher optical transmittance of 84.79% than the values (4.625 x 10(-4) Omega cm and 78.36%) of the single AIO film, due to the high conductivity of the metallic Ag layer and the antireflection effect of the symmetric AIO/Ag/AIO structure. In addition, we investigated the performances of OSCs with AIO/AgIAIO electrodes as a function of Ag interlayer thickness to determine the optimal Ag thickness to produce a high power conversion efficiency (PCE) of the OSCs. Based on the PCE of the OSCs, we correlated the performance of the OSCs with the Ag interlayer thickness in the AIO/Ag/AIO multilayer and suggested a possible mechanism to explain the dependency of PCE on Ag thickness in AIO/Ag/AIO multilayer electrodes. (C) 2015 Elsevier B.V. All rights reserved.