Custom-made masks enabled the simultaneous fabrication of up to four devices with a 4.32.2 cm 2 photoactive area onto 53 cm 2 ITO substrates (Supplementary Fig. ). A representative 10 cm device sustained an open-circuit voltage (VOC) of 1.04 V and a moderately high short circuit current density (JSC) of -17.2 mA cm -2 , similar to those of smaller 8pixel devices. A significantly lower fill factor (FF) of 28.7% could be traced back to the sheet resistance of conductive ITO glass (15 Ω sq. -1 ), which is known to induce resistive losses over larger areas, especially at absolute current densities beyond 100 mA. Still, the device attained a PV cell efficiency (PCE) of 5.3% (Fig. ), representing a four-fold improvement over the efficiency of our solution-processed devices. 47