High-Efficiency Organic Photovoltaics using Eutectic Acceptor Fibrils to Achieve Current Amplification

The intrinsic electronic properties of donor (D) and acceptor (A) materials in coupling with morphological features dictate the output in organic solar cells (OSCs). New physical properties of intimate eutectic mixing are used in nonfullerene-acceptor-based D-A(1)-A(2) ternary blends to fine-tune the bulk heterojunction thin film morphology as well as their electronic properties. With enhanced thin film crystallinity and improved carrier transport, a significant J(SC) amplification is achieved due to the formation of eutectic fibrillar lamellae and reduced defects state density. Material wise, aligned cascading energy levels with much larger driving force, and suppressed recombination channels confirm efficient charge transfer and transport, enabling an improved power conversion efficiency (PCE) of 17.84%. These results reveal the importance of utilizing specific material interactions to control the crystalline habit in blended films to form a well-suited morphology in guiding superior performances, which is of high demand in the next episode of OSC fabrication toward 20% PCE.

Automated summary

By utilizing the new physical properties of intimate eutectic mixing in nonfullerene-acceptor-based D-A(1)-A(2) ternary blends, the thin film morphology and electronic properties in organic solar cells are finely tuned to achieve significant enhancement in power conversion efficiency (PCE). The aligned cascading energy levels and suppressed recombination channels confirm efficient charge transfer and transport, leading to an improved PCE of 17.84%.