A novel n‐type dimer dopant for semiconducting polymers

Efficient and stable doping of organic semiconductors is crucial for adjusting their electrical properties. This work focuses on a novel n ‐type dopant which releases two electrons per dopant molecule. The dopant's capability was tested with two semiconducting polymers, i.e. poly[ N,N´ ‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐ alt ‐5,5′‐(2,2′‐bithiophene) (P(NDI2OD‐T2)) and poly(9,9‐dioctylfluorene‐ alt ‐benzothiadiazole) (F8BT). At an optimal doping concentration of 10% (dopant per polymer monomer), the conductivity of P(NDI2OD‐T2) increased by almost 5 orders of magnitude, comparable to other reported values for doped P(NDI2OD‐T2) films. Activation of doping is needless for this material combination. The doped films showed minimal dopant drift under electric fields and good temperature stability, but low air stability. The dopant is capable of doping even polymers with an electron affinity of ca 2.8 eV, as demonstrated with F8BT. This novel dopant enhances the abilities of molecular n ‐type doping for the community.