Effect of crystal size distribution on thermoelectric performance for Lanthanum-doped strontium titanate bulk material

Abstract

Effect of crystal size distribution on thermoelectric performance of Lanthanum-doped strontium titanate ( La - SrTiO 3) ceramics are investigated in this study. Thermoelectric performance measurement, coupled with microstructure studies, shows that the electrical conductivity strongly depends on the crystal size, potential barrier on the grain boundary and porosity. Meantime, because the average potential barriers height are increased along with the reduction of crystal size, the Seebeck coefficients are increased by energy filtering effect at the large number of grain boundaries. As a result, by controlling of crystal size distribution, ZT value of La - SrTiO 3 is improved.

Electronic transport and the thermoelectric properties of donor-doped SrTiO3

“…The latter arises from the large effective mass of the Ti 3d-based carriers [16]. STO is a wide-bandgap insulator (E g = 3.2 eV) [17], and electron doping has been universally adopted as a means to improve its TE performance, with typical routes based on La doping at the Sr (A) site [9,[18][19][20] and Nb doping at the Ti (B) site [12,21,22]. Other potential dopants for tuning the electrical properties include trivalent rare-earth elements such as Pr [22], Nd [23], and Ce, Sm, Gd, Dy and Y [24] at the A site and other pentavalent or hexavalent elements including Ta [25], Mo [19], and W [26] at the B site.…”