Air-stable n-type dopant for organic semiconductors via a single-photon catalytic process

Controlled doping of conjugated polymer-based semiconductors is crucial for optoelectronic applications. While p-type doping of conjugated polymers can be readily achieved with a variety of oxidants, n-type doping is more challenging, usually requiring highly reactive reducing agents. Here, we demonstrate that an air-stable photoredox catalyst (acridinium salt), together with a mild and air-stable reducing agent (amine), can effectively dope common n-type conjugated polymers under light at room temperature, yielding conductivity values on par with the highest obtained via other means. We elucidate the mechanism and show that this photoredox n-doping occurs via a one-photon-one-electron transfer process that is catalytic in nature. This simple and facile n-doping approach opens more avenues for doping organic semiconductors with the potential to revolutionize device design and substantially enhance doping efficiency.