High-performance polymer photovoltaic devices with inverted structure prepared by thermal lamination

Use of a lamination process for the introduction of Au electrode, instead of conventional metal evaporation, improved the power conversion efficiency (PCE) of inverted-structure photovoltaic devices front 1.6% to 2.6% based on a bulk heterojunction of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C-61 butyric acid methyl ester (PCBM). X-ray photoelectron spectroscopy indicated that a thin layer of P3HT is spontaneously formed at the air/polymer blend layer interface during the spin-coating process. It is suggested that the vacuum-evaporated gold could destroy the surface-segregated thin layer of P3HT, while the lamination process preserves the surface structure working as ail electron-blocking layer. The insertion of a PEDOT:PSS layer, between the metal electrode and polymer layer, in the lamination process further improved the PCE to 3.3% with a short-circuit current density of 9.94 mA cm(-2), an open-circuit voltage of 0.60V, and a fill factor of 55% under AM1.5 100 mW cm(-2) irradiation. (C) 2009 Elsevier B.V. All rights reserved.