Split-functional p-type dopants for organic semiconductors

Organic semiconductors (OSCs) are extensively used in next-generation optoelectronic devices. Efficient and stable electronic doping broadens their applications. Traditional doping methods, especially metal salts, often face challenges such as low doping efficiency, ion migration, instability under ambient conditions, limited compatibility with hole-transport layers, and reliance on additives or complex processing. Here, metal-free modular split-functional dopant systems are developed. By separating charge-transfer and thermal-stability functions, this design enables independent tuning of charge-transfer ability, solubility, compatibility during film formation, and stability of the doped films. This strategy enables rapid, additive-free p-type doping under ambient conditions across various OSCs with higher efficiency than metal-salt-based doping. OSC films doped with split-functional systems exhibit uniform doping and reduced ion migration under applied electric fields, unlike traditionally doped films. The functionality introduced by the dopants enhance the thermal stability of the doped films, which remain stable for >1000 hours under continuous thermal stress at 100 °C. These dopant systems are compatible with a wide range of hole-transport materials without requiring additional additives. The synthetic simplicity, versatility, ambient processibility and scalability of this approach make split-functional dopants a promising platform for creating highly stable hole-transport layers in perovskite solar cells, enabling the development of efficient, stable devices.