External serial connection without layer patterning for organic solar cells

This paper proposes a novel alternative to conventional internal serial connection, where precise patterning and scribing of organic layers can be eliminated. Adjacent cells can be made nearer for better space-utilization and higher voltages per unit area. Also, blade coating is proposed as the fabrication method as it has low material wastage (less than 5%), easily scalable to large area, has high film uniformity and has high throughput due to its roll-to-roll potential. This paper demonstrates 3-cells large area (12.98 cm²) external serial connection organic solar cells (OSCs) using the material poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) and 2,6-Bis(trimethyltin)-4, 8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo [1,2-b:4,5-b′]dithiophene:6,6-phenyl C71-butyric acid methyl ester (PBDTTT-CT:PC₇₁BM) respectively. The power conversion efficiencies (PCEs) of the resulting 3-cells modules are 2.0% and 4.1% respectively.