Abstract
Modulating the structure and property of hole‐transporting organic semiconductors is of paramount importance for high‐efficiency and stable perovskite solar cells (PSCs). This work reports a low‐cost peri‐xanthenoxanthene based small‐molecule P1, which is prepared at a total yield of 82 % using a three‐step synthetic route from the low‐cost starting material 2‐naphthol. P1 molecules stack in one‐dimensional columnar arrangement characteristic of strong intermolecular π–π interactions, contributing to the formation of a solution‐processed, semicrystalline thin‐film exhibiting one order of magnitude higher hole mobility than the amorphous one based on the state‐of‐the art hole‐transporter, 2,2‐7,7‐tetrakis(N,N′‐di‐paramethoxy‐phenylamine 9,9′‐spirobifluorene (spiro‐OMeTAD). PSCs employing P1 as the hole‐transporting layer attain a high efficiency of 19.8 % at the standard AM 1.5 G conditions, and good long‐term stability under continuous full sunlight exposure at 40 °C.
Easy, efficient, and stable: A low‐cost peri‐xanthenoxanthene‐centred columnar‐stacking organic semiconductor has been prepared and used as a hole‐transporter in perovskite solar cells achieving a power conversion efficiency of 19.8 % and good long‐term stability under continuous full sunlight exposure at 40 °C.