Degradation-assisted doping of organic semiconductors: a strategy towards higher p-doping efficiency enabled by Lewis acids

The chemical doping of organic semiconductors with molecular dopants is crucial for high-performance organic electronic devices. Chemically stable dopants are commonly used, enabling electron transfer until a thermodynamic equilibrium is reached, which then terminates the doping process. Here, we demonstrate that employing p-dopants that chemically degrade after electron transfer via their radical anion can increase hole densities in the semiconductor host by up to two orders of magnitude. This degradation-assisted doping (DAD) mechanism represents a new doping paradigm for organic semiconductors in which the electron affinity of the doping agent only enables a limited amount of charge transfer. Subsequent dopant degradation effectively removes its products from co-defining the thermodynamic equilibrium and thus allows the doping reaction to persist. We demonstrate that the prototypical Lewis acid tris(pentafluorophenyl)borane (BCF) exemplifies degradation-assisted doping, and provide the theoretical framework for this doping strategy offering new avenues for optimizing charge carrier densities in organic semiconductors.