ITO

1. A Universal Method to Produce Low–Work Function Electrodes for Organic Electronics Antoine Kahn, Princeton University, DMR 1005892 (b) (a) In this work, we demonstrate that ultra-thin (1-2 nm) surface modifier films made of the type of PEIE polymer depicted in (a) and containing aliphatic amine groups, applied by simple spin-coating under ambient conditions, can lower the work function of numerous and very diverse types of materials, such as metals, organic films, or semiconductor oxides, by 1 eV or more (see (b) for photoemission measurements). Easily processed, air-stable low work function electrodes and films are exceedingly important for the fabrication of electron-injecting and -extracting electrodes for large-area organic electronics. We demonstrate the applicability of these polymer modifiers in devices such as bulk-heterojunction organic solar cells in which PEIE is used to create a low-work function ITO-based contact (c), leading to remarkably good performance (d). Use of PEIE to transform gold into an very good electron injector in an electron-channel field effect transistor was also demonstrated (d) (c) ITO Y. Zhou, C. Fuentes-Hernandez, J. Shim, J. Meyer, A.J. Giordano, H. Li, Paul Winget, T. Papadopoulos, H. Cheun, J. Kim, M. Fenoll, A. Dindar, W. Haske, E. Najafabadi, T.M. Khan, H. Sojoudi, S. Barlow, S. Graham, J.-L. Brédas, S.R. Marder, A. Kahn, B. Kippelen, Science, 336, 327 (2012)