Nankai University’s Yongsheng Chen in EES: 19.6%! Additive-free binary devices achieve nearly 20% efficiency!

Based on this, Zhao Yan of Fudan University, Kan Bin and Chen Yongsheng of Nankai University, among others Using a邻-quinone-mediated cyclization strategy, we synthesized fused polycyclic aromatic frameworks and the corresponding electron acceptors CD-1 and CD-2, both of which exhibit highly packed three-dimensional interpenetrating network structures in single crystals. Therefore, the newly designed receptor exhibits remarkable electron-transport properties; for instance, organic field-effect transistor devices based on CD-2 achieve mobilities as high as 1.1 cm²·V⁻¹. ^-1 ·s ^-1 high electron mobility. Notably, additive-free binary organic photovoltaic devices incorporating CD-1 exhibit a power conversion efficiency (PCE) of 19.6%, with well-balanced open-circuit voltage and short-circuit current density; similarly, additive-free binary devices based on CD-2 also achieve a PCE of 19.1%. These results not only highlight the potential of novel molecular design strategies in the development of high-performance electron acceptors, but also provide valuable insights into achieving high efficiency in organic optoelectronic devices. The paper was recently published as “ “‘Head Surgery’ of Polycyclic o-Quinones with Cyanated Aromatic Rings towards High Electron Mobility Acceptors Enable 19.6% Additive-Free Binary Organic Solar Cells” was published in the journal Energy & Environmental Science Above 。

In summary, the authors and collaborators leveraged previously reported polycyclic ortho-quinones in cyclization–aromatization reactions to develop a series of novel electron acceptors featuring centrally extended π-conjugated frameworks. Single-crystal structural analysis revealed that both CD-1 and CD-2 possess tightly interpenetrating three-dimensional network architectures with high packing densities, thereby ensuring excellent charge transport properties. Due to its high packing coefficient and deep LUMO energy level, CD-2 exhibits 1.1 cm in both single-crystal and thin-film OFET devices, respectively. ² V ^-1 s ^-1 and 0.5 cm ² V ^-1 s ^-1 its electron mobility—both of these represent the highest values reported for NFA-based devices. In OSC devices, CD-1 achieves an efficiency of 19.6% in binary blends thanks to its relatively high LUMO energy level and favorable morphology when blended with the polymer donor D18, which also ranks among the highest efficiencies reported for additive-free devices. This work offers new insights into the design and synthesis of high-performance electron acceptors, emphasizing the importance of extending the central unit while also opening up additional avenues for the structural optimization and functionalization of such acceptors.