Japan's new molecule to produce efficient organic thin-film solar cells

Researchers at Osaka Metropolitan University have developed a novel donor–acceptor–donor molecule named TISQ that can spontaneously self-assemble into nanoscale p/n heterojunctions, which are critical for efficient charge separation and transport in organic thin-film solar cells. Unlike traditional methods that physically mix p-type and n-type molecules—often resulting in inconsistent and unstable interfaces—TISQ integrates both semiconductor components within a single molecule. This design leverages hydrogen bonding via amide groups to promote controlled self-assembly, potentially leading to more stable and reproducible solar cell structures. TISQ exhibits two distinct aggregate forms depending on the solvent environment: nanoparticle-like J-type aggregates in polar solvents and nanofiber-like H-type aggregates in low-polarity solvents. These aggregates differ in their electronic properties, with J-type aggregates demonstrating nearly double the photocurrent response compared to H-type. The team successfully incorporated TISQ as a single-component photoactive material in organic thin-film solar cells, confirming the