Fluorinated Alkyl Chains Terminated Polar Glycol Ether Side Chain for N-Type Organic Thermoelectrics with Enhanced Performance and Air Stability.

N-type organic thermoelectric materials with excellent device performance and air stability are critically important for practical applications in organic thermoelectric devices. However, the design and synthesis of air-stable n-type conductive materials with high electrical conductivities remain a significant challenge. In this paper, a new strategy is reported to enhance the thermoelectric performance and air stability of naphthalenediimide (NDI)-dialkoxybithiazole-based conjugated polymers by introducing fluorinated alkyl chains terminated polar glycol ether side chains into the NDI unit. After molecular doping with 4-(2,3-dihydro-1,3-dimethyl-1H-benzoimidazol-2-yl) phenyl)-N, N-dimethylbenzenamine (N-DMBI), the doped films of the fluorinated alkyl side-chain modified conjugated polymer exhibit higher electrical conductivity, thus resulting in a greater power factor; and better air stability compared to those of the unmodified polymer with the same conjugated backbone. The work provides insights into material design for the future development of air-stable n-type organic thermoelectrics.