Bi-functional organic salts for ambient processing of organic semiconductors

Ambient processing of organic semiconductors (OSCs) is crucial for scalable, cost-effective device manufacturing; however, it is often hindered by uncontrolled, unintentional interactions with oxygen. Mitigating such interactions and even leveraging them to enhance the optoelectronic properties of OSCs will further enhance the application of OSCs in low-cost, printable optoelectronic devices. Here, we developed two organic salt additives to modify the electronic properties of OSCs during thin-film preparation under ambient conditions. The addition of these bespoke salts to commonly used hole-transport materials (HTMs) significantly increases the conductivity and charge-carrier mobility of the OSCs. We elucidate here the underlying mechanism responsible for this improvement: the cationic component of the salts scavenges superoxide species generated during ambient processing and storage, while the anionic component reduces electronic trap densities in the OSC films. Owing to the generality of this mechanism, these additives offer a new and versatile strategy for enhancing the optoelectronic performance of organic semiconductors processed in ambient conditions.