Tunable thermoelectric performance in metal–organic framework Ni(BDC) studied by first principles

Abstract

Metal–organic frameworks (MOFs) have unique advantages in thermoelectric applications due to their low lattice thermal conductivity. However, the low electrical conductivity limits their thermoelectric performance. In this work, we report a strategy to improve the electrical conductivity of MOFs by infiltrating pillar molecules into the layered MOFs. First principles studies indicate that after the Ni(BDC) (BDC = terephthalic) is infiltrated with DABCO (1,4-diazabicyclo[2,2,2]octane), the electrical conductivity of Ni(BDC) demonstrates a significant increase, and the power factor finally reaches 1.5 × 10−3 W m−1 K−2 at 300 K. The high electrical conductivity arises from the interaction between 3dz2 orbital of Ni and the 2pz orbital of N in DABCO. The p–d orbital coupling leads to the electron delocalization on HOMO and also the decrease in carriers effective mass. Our results provide a useful strategy for increasing the conductivity of MOFs and suggest that MOFs can be a promising class of thermoelectric materials.