Precise synthesis of advanced polyarylamines for efficient perovskite solar cells

Although being highly demanded in organic electronics, functional conjugated polymers face challenges on scalable synthesis with batch uniformities. Here a reactivity-regulated sequent cross-coupling carbon-nitrogen polycondensation method is developed to enable the precise synthesis of functional polyarylamines with excellent batch-to-batch uniformity. It is revealed that the stepwise regulation of intermediate reactivities is key to accomplish controllable polycondensation via two sequent palladium-promoted carbon-nitrogen coupling cycles, which is distinct to the unicyclic carbon-carbon coupling. A variety of polyarylamines are prepared to improve the material functionalities, where a ternary polymer consisting of polar substituents is shown to optimize the interfacial and bulk properties of perovskite layers fabricated on top. The corresponding inverted perovskite solar cells achieved remarkable power conversion efficiencies of 25.2% (active area, 5.97 mm²) and 23.2% (active area, 128 mm²), along with decent operational stabilities. Overall, this work provides an effective polymerization method for advanced conjugated polymers to enable high-performance optoelectronics.