Self-assembly supramolecules to enhance electrical conductivity of polyaniline for a flexible organic solar cells anode

Abstract

A high performance and cost effective polyaniline doped with camphorsulfonic acid (PANI:CSA) based thin film was prepared for a flexible electrode. A high crystalline structure was introduced to prevent the decreased orientation of PANI film to overcome a conductivity dropping with decreasing film thickness because of the recoiling of the polymer chains. An optimum structure is selected according to the various analyses such as self-assembled degree, crystallinity, and the blending properties with PANI. The additive, named self-assembly supramolecules (SAS), was successfully blended with PANI chains. PANI film blended with the most suitable SAS (PANI:CSA/SAS18) exhibited high conductivity of 843 S/cm and a high optical transparency of 86% at 550 nm that was thinner than 200 nm of film thickness. The flexible organic solar cells (OSCs) device adapted to our electrode shows a higher power conversion efficiency of 1.73% than a pristine PANI:CSA electrode at 0.40%. Furthermore, it was possible to induce long environmental stability under numerous device operating cycles since PANI:CSA/SAS18 had a lower acidity compared with the PEDOT:PSS conventional polymer electrode. The efficiency of our OSC device remains more than 90% after 500 h, while that of OSC device made of PEDOT:PSS decreased approximately 30% of their initial efficiency after 500 h. The PANI based OSCs electrode developed in this study has the potential for consideration as a novel polymer electrode in a flexible display. (C) 2012 Elsevier B.V. All rights reserved.