We have designed and fabricated dye solar cell (DSC) modules with optimized geometries and processes. Integrated interconnections were made following the “Z” architecture for series connections. Several modules were prepared varying the materials, multilayer combination of the TiO2 active layers, and the fabrication processes. With the best combination of TiO2 multilayers, titanium tetrachloride (TiCl4) treatment, a back reflector/diffusor, and optimized layout of cells via simulations, we fabricated a DSC module with a conversion efficiency of 6.9% on 43 cm2 aperture area and 9.4% on active area. This result confirms that an effective scale-up of high performance Z-series-connected DSC modules can be achieved comparable with other thin film technology. Note that the materials used to produce the devices of this work are all commercially available: an important result for a technology that is being developed for industrial application. Copyright © 2012 John Wiley & Sons, Ltd.