Carrier type control in cement-based thermoelectric composites with carbon nanotube and SrTiO3 nanoparticles

Abstract

Cement-based thermoelectric material can achieve conversion between waste heat and electric energy, and thus be considered as potential candidates for green intelligent buildings. In this paper, the thermoelectric properties of the cement composites with SrTiO3 nanoparticles and carbon nanotubes were investigated for the first time. For the cement composites at an age of 28 days without drying process, the ionic Seebeck effect plays an important role in influencing the thermovoltage value. The carbon nanotube reinforced cement composite after drying shows n-type thermoelectric characteristic, however, the addition of pristine and annealed SrTiO3 nanoparticles can lead to p-type and n-type semiconducting characteristics respectively, which indicates that the carrier type of cement composites is primarily determined by the ceramic filler. The power factors of composites with 0.50 wt% pristine SrTiO3 and 1.0 wt% annealed SrTiO3 are 0.65 × 10−6 and 1.61 × 10−6 μW cm−1 K−2, which are 8.6 and 21 times higher than that of CNT reinforced sample respectively. In addition, the compressive strength of cement composites with SrTiO3 nanoparticles and carbon nanotubes is enhanced significantly.