Carbon nanotubes enhanced Seebeck coefficient and power factor of rutile TiO2.
The Seebeck coefficient, according to Ioffe's approximation, is inversely proportional to carrier density and decreases with doping. Herein, we find that the incorporation of multi-walled carbon nanotubes into rutile TiO2 improves the electrical conductivity and Seebeck coefficient at a low filling fraction of tubes; moreover, the former was due to the lengthening of the mean free path and doping modified carrier mobility for the latter. Tube-oxide mixing also causes significant phonon drag at the interfaces and the reduced thermal conductivity was verified by the promoted figure of merit.
Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan. wkhsu@mx.nthu.edu.tw.
Yao-Cheng
YC
Lai
Hsin-Jung
HJ
Tsai
Chia-I
CI
Hung
Hiroyuki
H
Fujishiro
Tomoyuki
T
Naito
Wen-Kuang
WK
Hsu