Thermoelectric Properties of an Indandione‐Terminated Quinoidal Compound: Effect of the n‐Type Dopants†

Comprehensive Summary The investigation of n‐type doping holds a significant interest for the application of thermoelectrics. Herein, the doping of an indandione‐terminated compound Q‐4F with a singlet open‐shell ground state was studied using two n‐dopants N‐DMBI and LCV. Both of these two dopants can effectively dope Q‐4F due to the large offset between the singly occupied molecular orbital (SOMO) of dopants and the lowest unoccupied molecular orbital (LUMO) of Q‐4F. N‐DMBI has a higher doping ability than LCV as demonstrated by the UV‐ vis ‐NIR and EPR measurements. However, in comparison to N‐DMBI doped Q‐4F, LCV doped system exhibits much higher electrical conductivity and power factor due to its unperturbed molecular packing and favorable morphology after doping. The optimal conductivity of LCV doped Q‐4F is 7.16 × 10 –2 ± 0.16 S·cm –1 and the highest power factor reaches 12.3 ± 0.85 μW·m –1 ·K –2 . These results demonstrate that the modulation of n‐dopants is a powerful strategy to balance the doping efficiency and microstructure toward a maximum thermoelectric performance.