  Carbon nanotubes (CNTs) have recently attracted attention as materials for
flexible thermoelectric devices. To provide theoretical guideline of how
defects influence the thermoelectric performance of CNTs, we theoretically
studied the effects of defects (vacancies and Stone-Wales defects) on its
thermoelectric properties; thermal conductance, electrical conductance, and
Seebeck coefficient. The results revealed that the defects mostly strongly
suppresses the electron conductance, and deteriorates the thermoelectric
performance of a CNT. By plugging in the results and the intertube-junction
properties into the network model, we further show that the defects with
realistic concentrations can significantly degrade the thermoelectric
performance of CNT-based networks. Our findings indicate the importance of the
purification of CNTs for improving CNT-based thermoelectrics.
