High-performance ITO-free spray-processed polymer solar cells with incorporating ink-jet printed grid

Highly efficient ITO-free polymer solar cells (PSCs) based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) have been fabricated by a combination of inkjet-printing and spray processes. A hybrid transparent conducting electrode consisting of printed silver (Ag) grids and highly conductive poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PH1000) was used as an alternative to indium-tin oxide (ITO). Spray process incorporating with printed Ag grids played a critical role in improving the interfacial contact between Ag grids and photoactive layer, and thus enhanced the performance of ITO-free large-area PSC. The ITO-free PSC (device area = 0.3 cm(2)) prepared here has a comparable performance of 2.86%. The average PCE of 2.34% was achieved in the ITO-free PSC with a large electrode area (8 cm(2)) fabricated herein by the combination of inkjet-printed grid and spray processes. This result is much better than ITO-based large-area PSC generally reported. (C) 2013 Elsevier B. V. All rights reserved.