Self-Doping a Hole-Transporting Layer Based on a Conjugated Polyelectrolyte Enables Efficient and Stable Inverted Perovskite Solar Cells

The interface material is an indispensable part of perovskite solar cells (PSCs) because of its special functions. In this work, a conjugated polyelectrolyte, PTPADT-SO3Na, was synthesized and introduced to the inverted PSCs as a hole-transporting layer (HTL). PTPADT-SO3Na exhibits a close level of valence band to perovskites and good conductivity because of a self-doping effect. Accordingly, the PTPADT-SO3Na device shows excellent performances with a maximum efficiency of 18.15%, which is better than that of the device with a typical HTL [poly­(3,4-ethylenedioxythiophene):poly­(styrene sulfonate)]. Meanwhile, the PTPADT-SO3Na PSC exhibits outstanding stability in an ambient atmosphere (humidity of 50%) and heating condition (85 °C).