Low-Cost Nucleophilic Organic Bases as n-Dopants for Organic Field-Effect Transistors and Thermoelectric Devices

Doping is a powerful technique for tuning the electrical properties of organic semiconductors (OSCs). Although numerous studies are performed on OSC doping, thus far only a few n-type dopants have been developed. Herein, two low-cost nucleophilic organic bases are reported, namely 1,5,7-Triazabicyclo [4.4.0] dec-5-ene (TBD) and 1,5-Diazabicyclo [4.3.0] non-5-ene (DBN) for n-doping of OSCs. The two dopants are found to significantly enhance the electrical conductivity of OSCs. In particular, compared to the classic n-dopant 4-(2,3-Dihydro-1,3-dimethyl-1 H -benzimidazol-2-yl)- N , N -dimethylbenzylamine ( N -DMBI), DBN results in significantly higher conductivity and also lower activation energy in N2200 films, indicating its high doping performance. The utilization of the n-dopants for improving device performance and controlling the device polarity of organic field-effect transistors are demonstrated. Furthermore, these dopants are employed for fabricating organic thermoelectric devices, and the power factor value of DBN-doped N2200 films is found to be about 1.6 times higher than that of N -DMBI-doped films. These results show the feasibility of using low-cost organic bases as efficient n-dopants and demonstrate their promising applications in organic electronics.