A Doped Hole Transport Layer Qualified for 100 °C‐Tolerant Perovskite Solar Cells.

Due to the extremely low intrinsic carrier density and disordered nature of organic semiconductor thin films, unintentional or intentional chemical doping is inevitable for sufficiently high carrier density and charge mobility unless charges are either injected from appropriate electrodes or by photoexcitation. However, doping often results in a reduction in thermal tolerance. The charge transport layers for thermostable perovskite solar cells (PSCs) need to possess a heat‐resistant morphology and to suppress the diffusion of volatile species. Here the authors report a molecular semiconductor with a molecular mass of >2000 Daltons but free of any flexible side chains. Its air‐doped composite with thermally stable acid salt exhibits an electrical conductivity of over 50 μS cm−1 and a glass transition temperature of 142 °C. Molecular dynamics simulations reveal that molecules and ions in this composite do not experience significant translational motion even at 150 °C. These unusual features allow for the fabrication of 21.5%‐efficiency PSCs that can withstand 200 h at 100 °C. [ABSTRACT FROM AUTHOR]