Novel Organic Superbase Dopants for Ultraefficient N‐Doping of Organic Semiconductors

Doping is a powerful technique for engineering the electrical properties of organic semiconductors (OSCs), yet efficient n‐doping of OSCs remains a central challenge. Herein, the discovery of two organic superbase dopants, namely P2‐t‐Bu and P4‐t‐Bu as ultra‐efficient n‐dopants for OSCs is reported. Typical n‐type semiconductors such as N2200 and PC61BM are shown to experience a significant increase of conductivity upon doping by the two dopants. In particular, the optimized electrical conductivity of P2‐t‐Bu‐doped PC61BM reaches a record‐high value of 2.64 S cm−1. The polaron generation efficiency of P2‐t‐Bu‐doped in PC61BM is found to be over 35%, which is 2–3 times higher than that of benchmark n‐dopant N‐DMBI. In addition, a deprotonation‐initiated, nucleophilic‐attack‐based n‐doping mechanism is proposed for the organic superbases, which involves the deprotonation of OSC molecules, the nucleophilic attack of the resulting carbanions on the OSC's π‐bonds, and the subsequent n‐doping through single electron transfer process between the anionized and neutral OSCs. This work highlights organic superbases as promising n‐dopants for OSCs and opens up opportunities to explore and develop highly efficient n‐dopants. The discovery of two organic superbase dopants as ultra‐efficient n‐dopants for OSCs is reported. In‐depth studies reveal that the dopants lead to record‐high conductivity in doped N2200 and PC61BM films, and exhibit particularly high polaron generation efficiency and doping efficiency. A possible deprotonation‐induced nucleophilic‐attack n‐doping mechanism is suggested for the organic superbase dopants.