Stable and uniform self-assembled organic diradical molecules for perovskite photovoltaics

Organic self-assembled molecules (SAMs), which are widely used in perovskite solar cells (PSCs), should exhibit enhanced performance to support the ongoing advancement of perovskite photovoltaics. We designed diradical SAMs through a coplanar conjugation of a donor-acceptor strategy to facilitate hole transport across the SAMs. The diradical SAMs exhibited high photothermal and electrochemical stability as well as improved assembly uniformity and large-area solution processability attributed to molecular steric hindrance design. We used an advanced scanning electrochemical cell microscopy–thin-layer cyclic voltammetry technique to accurately determine the carrier transfer rate, stability, and assembly properties of the SAMs. Ultimately, the efficiencies of the PSCs exceeded 26.3%, minimodules (10.05 cm 2 ) reached 23.6%, and perovskite-silicon tandem devices (1 cm 2 ) surpassed 34.2%. The PSCs maintained >97% after 2000 hours tracking at 45°C.