Crystallization-sequence engineering enables organic solar cell modules with efficiencies exceeding 18%

• Crystallization-sequence engineering enables organic solar cell modules to achieve efficiencies exceeding 18%. • The approach addresses the thickness constraint of the active layer, facilitating scalable manufacturing. • Thicker active layers are achieved without compromising efficiency, improving light harvesting and processing window. • The technique mitigates recombination and phase separation issues in thick films, enhancing charge extraction.