Fully Roll-to-Roll Printed P3HT/Indene-C60-Bisadduct Modules with High Open-Circuit Voltage and Efficiency

Indene-C60-bisadduct (ICBA) can represent an excellent choice as an acceptor of organic solar cells due to the, at most, similar cost, higher efficiency, and higher open-circuit voltage (VOC) obtained in small-scale devices compared to phenyl[60]butyrate methyl ester ([60]PCBM). We have investigated ICBA in printed solar cells and assessed the upscale of the printing process to a roll-to-roll (R2R) pilot production. Performances of poly(3-hexylthiophene):ICBA solar cells are confirmed to be superior compared to [60]PCBM. Using large scale 2D R2R printing techniques, with both active material systems excellent processability, reproducibility, and yield are reached. At first, ICBA based large area modules (57 cm2) showed significant loss in efficiency. However, stressing the devices by exposure to sunlight was found to lead high efficiency modules with a VOC of 0.78 V per cell and a PCE of 3.4%. This is among the highest VOC per cell values realized with fully R2R processed organic photovoltaic modules and among the highest PCEs with P3HT based R2R processed modules. Imaging techniques have allowed to identify that stressing with sunlight partially burns shunts and recovers S-shaped behavior in the ICBA-based modules.