A Novel Way to Enhance the Thermoelectric Efficiency of Carbon Nanotube through Cobaltocene‐decamethyl Cobaltocene Encapsulation

Abstract

AbstractHerein, we report a novel way to enhance the thermoelectric figure of merit (ZT) of carbon nanotube (CNT) by a factor as large as of 103. Our non‐equilibrium Green's function based density functional theory study on a (17, 0) CNT proved that such a huge change in the ZT of CNT is possible when the symmetry of the material is broken by a combination of cobaltocene and decamethyl cobaltocene encapsulation. The calculations also indicate that pristine carbon nanotube, which is a p‐type thermoelectric material, turns into an n‐type material upon such encapsulation. The detail analyses reveal that the reason behind this remarkable enhancement of ZT is mainly attributed to the sharp rise in the electrical conductance of cobaltocene moiety encapsulated CNT with respect to pristine CNT. We have noticed that symmetry breaking has resulted in the removal of degeneracy of HOMO (highest occupied molecular orbital), HOMO‐1 and LUMO (lowest unoccupied molecular orbital), LUMO+1 which eventually leads to a significant decrease in the HOMO‐LUMO gap of the system and subsequently a 400 times increase in the overall electrical conductance of the thermoelectric device.