Case Study on Impact of Geometric Fill Factor on the Effectiveness of Organic Solar Cells

This study investigates the impact of the geometric fill factor (GFF) on the practical performance of organic solar cell (OSC) modules fabricated by two distinct approaches: a conventional hand‐made method and UV nanosecond laser patterning technique. Using the optimized PM6:L8‐BO photoactive system, two OSC modules—each comprising three sub‐cells—were fabricated under the same device dimensions (35 × 35 mm). Laser‐patterned module exhibited a substantial enhancement in GFF from 62.73% to 98.41%, resulting in an increase in the maximum output power ( P max ) from 69.67 mW to 124.25 mW. To evaluate the practical energy harvesting capability, capacitor‐charging experiments were performed under identical illumination conditions. The laser‐patterned module reached the target voltage of 2.5 V in 380 seconds, whereas the hand‐made module required 610 s to reach the same voltage. These results demonstrate that a cost‐effective UV nanosecond laser system can effectively optimize the GFF and nearly double the output power of OSC modules. Furthermore, comprehensive stability evaluations emphasize the importance of ensuring process reliability, highlighting the key technological challenges that must be addressed for future industrial implementation.