“Head surgery” of polycyclic o-quinones with cyanated aromatic rings towards high electron mobility acceptors enables 19.6% efficiency in additive-free binary organic solar cells

Abstract

The development of high-performance organic electron acceptors is pivotal for advancing organic optoelectronic devices. In this paper, a new synthetic approach was developed to construct fused-ring aromatic backbones and the corresponding electron acceptors, namely CD-1 and CD-2, through an o-quinone-mediated cycloaromatization strategy. Both CD-1 and CD-2 exhibit a compact 3D interpenetrating network structure with high packing coefficient in a single crystal. Consequently, these newly designed acceptors demonstrate remarkable electron transport capability as evidenced from the high electron mobility over 1.1 cm² V⁻¹ s⁻¹ of CD-2 based organic field-effect transistor devices. Notably, the additive-free binary organic photovoltaic devices incorporating CD-1 exhibit power conversion efficiencies (PCEs) of 19.6% with well-balanced open-circuit voltage and short-circuit current density, and the corresponding additive-free binary devices based on CD-2 achieve a decent PCE of 19.1% as well. These results not only underline the potential of the new molecular design strategy in providing a robust platform for developing high-performance electron acceptors, but also offer valuable insights into the new design guidelines for achieving high efficiency in organic optoelectronic devices.