DOI: 10.1002/ente.201500150 Roll-to-Roll Slot–Die Coated Organic Photovoltaic (OPV) Modules with High Geometrical Fill Factors Yulia Galagan,* [a] Henri Fledderus, [b] Harrie Gorter, [b] Hero H. ’t Mannetje, [b] Santhosh Shanmugam, [a] Rajesh Mandamparambil, [c] Johan Bosman, [d] Jan- Eric J. M. Rubingh, [b] Jean-Pierre Teunissen, [b] Ahmed Salem, [b] Ike G. de Vries, [b] Ronn Andriessen, [a] and Wilhelm A. Groen [b, e] Introduction Roll-to-roll (R2R) printing and coating of organic photovol- taics (OPVs) show great potential for high-throughput pro- duction of cheap flexible solar cells. [1–6] Although many suc- cessful examples on integration of R2R coated and printed modules have been demonstrated, [7–9] there are still many issues that have to be solved before industrialization of these technologies. [10–12] Significant efforts are directed at the quali- ty control of the printed layers. [7, 13] The analysis of layer quality during the coating and a forecast as to whether or not the module will work can significantly increase the yield of the produced modules and therefore decrease the manu- facturing cost. Another important issue towards industrial manufacturing is the environmental aspect. None of the processing steps should result in harmful impacts on the en- vironment. However, typical solvents for photoactive materi- als are halogenated aromatic solvents, for example, chloro- benzene (CB) or ortho-dichlorobenzene (o-DCB). OPV de- vices show highest performance if produced using these sol- vents. Driven by environmental aspects and potential indus- trialization of OPV technologies several groups have demonstrated highly efficient OPV modules produced from non-halogenated solvents using R2R compatible tech- niques. [1, 14, 15] One of the remaining issues towards upscaling and mass production of OPVs is an increase in the active area of the modules. Currently R2R manufacturing of the OPV modules is mostly realized by coating of separate stripes, which are further interconnected into modules. The relatively high sheet resistance of typical electrodes limits the width of the stripe (cell width), and the rather low resolution of coating technologies [16, 17] is responsible for the large interconnection area. The typical geometrical fill factor (GFF, the ratio be- tween the active area and total area of the OPV module) re- ported for coated modules is in the range of 50–75 %. [18–20] However, even then, very precise printing or coating on a large areas with a moving substrate is required to achieve this relatively low geometric fill factor, which still presents Flexible semi-transparent organic photovoltaic (OPV) mod- ules were manufactured by roll-to-roll slot–die coating of three functional layers [ZnO, photoactive layer, and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)] and either the screen printing or inkjet print- ing of the top electrodes. A poly(3-hexylthiophene):[6,6] phenyl C61-butyric acid methyl ester (P3HT:PCBM) layer deposited from non-chlorinated solvents was used as the ab- sorber layer. The modules were realized by slot–die coating of the layers onto a laser-patterned polyethylene terephtha- late/indium-tin oxide (PET/ITO) substrate, followed by laser structuring of all coated layers. The top electrodes were real- ized by high-resolution printing, which, combined with laser patterning of other layers, enables manufacturing of the modules with high geometrical fill factor (92.5 %). The mod- ules have an active area of 156 cm 2 , and contain 13 serially interconnected cells. Two semitransparent electrodes (ITO from the bottom and PEDOT:PSS/Ag-grid from the top side) allow the absorption of photons incident from both sides. The performance of the modules was evaluated and compared among the modules by considering the following factors: (i) roll-to-roll slot–die coated vs. spin-coated layers, (ii) inkjet-printed vs. screen-printed top electrodes, (iii) top vs. bottom illumination. The demonstrated technology is one of the proven feasible ways towards industrial manufacturing of the OPV modules. [a] Dr. Y. Galagan, S. Shanmugam, Dr. R. Andriessen Holst Centre—Solliance, High Tech Campus 21 5656AE Eindhoven (The Netherlands) E-mail: yulia.galagan@tno.nl [b] H. Fledderus, H. Gorter, H. H. ’t Mannetje, J.-E. J. M. Rubingh, J.-P. Teunissen, A. Salem, I. G. de Vries, Prof.Dr. W. A. Groen Holst Centre, High Tech Campus 31 5656AE Eindhoven (The Netherlands) [c] Dr. R. Mandamparambil TNO Science and Industry, P.O. Box 6235 5600HE Eindhoven (The Netherlands) [d] Dr. J. Bosman Energy Research Centre of the Netherlands (ECN)—Solliance, High Tech Campus 21 5656AE Eindhoven (The Netherlands) [e] Prof. Dr. W. A. Groen Faculty of Aerospace Engineering, Delft University Kluyverweg 1, 2629 HS Delft (The Netherlands) Energy Technol. 2015, 3, 834 – 842 # 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 834