Buffer and anode-integrated WO3-doped In2O3 electrodes for PEDOT:PSS-free organic photovoltaics

Abstract

We developed PEDOT:PSS-free organic solar cells (OSCs) using WO3 and In2O3 (IWO) mixed electrodes acting as a buffer hole injection layer (HIL) and anode simultaneously. Through the co-sputtering and rapid thermal annealing (RTA) of WO3 and In2O3, we achieved buffer and anode-integrated transparent electrodes with a sheet resistance of 17 Ohm/square, a transmittance of 90.32%, and a work function of 4.83 eV, all of which are comparable to values obtained with a conventional ITO anode. Due to the existence of WO3 in the In2O3 matrix, OSCs fabricated on an IWO electrode with no acidic PEDOT:PSS buffer layer showed a PCE of 2.87%. Therefore, a transparent IWO electrode simultaneously acting as an HIL and anode layer can be considered a promising transparent electrode for cost-efficient and reliable OSCs because it could eliminate the use of acidic PEDOT: PSS buffer layer. (C) 2013 Elsevier B. V. All rights reserved.