Abstract
Consisting of heavy elements and favorable electronic structure, MoTe2 has great potential as a good thermoelectric material for heat-to-electricity conversion. While some experimental work has been performed on the p-type version, n-type MoTe2 is theoretically predicted to have a great conversion efficiency and is crucial for eventual device functionality, yet has not been explored. Here, the preparation and thermoelectric properties of n-type iodine-doped nano-polycrystalline MoTe2 are currently reported. Nano-polycrystalline MoTe2 − xIx is obtained by ball milling and spark plasma sintering techniques. The composition, morphology and crystal structure of the prepared materials were analyzed by XRD and FESEM, which indicated a homogeneous single phase. The measured transport properties over the temperature range of 298–823 K indicate that iodine doping greatly enhances the carrier concentration and corresponding power factor, and drastically reducing the thermal conductivity. The ECR (Electrical conductivity ratios) carrier scattering analysis demonstrates that dislocation scattering is the main mechanism throughout the experimental temperature range. With the temperature and doping increasing, the thermal conductivity was reduced rapidly, and the minimum value was 1.19 Wm− 1 K− 1 at 673 K. The maximum value of the figure merit ZT ~ 0.16 over 673–750 K, which is much higher than other reported values. These excellent properties imply that MoTe2 will be an efficient candidate for thermoelectric applications.
Highlights
In the past several decades, the urgent need for more efficient and environmental friendly energy conversion technologies has driven an increasing interest in the field of thermoelectric (TE) materials, which are capable of converting heat into electricity[1,2,3,4]
N-type nano-polycrystalline MoTe2-xIx samples were fabricated for first time by solid-state reaction, ball milling and spark plasma sintering
The conclusions can be described below: (1) The X-ray diffraction (XRD) patterns of all the samples indicate that the main diffraction peaks correspond to the hexagonal MoTe2 phase (PDF#72-0117) with no texture of the c-axis plane
Summary
In the past several decades, the urgent need for more efficient and environmental friendly energy conversion technologies has driven an increasing interest in the field of thermoelectric (TE) materials, which are capable of converting heat into electricity[1,2,3,4]. Two dimensional and single-crystal p-type MoTe2 doped with transition metal impurities (such as Nb and Ta) have been researched for the possible enhancement of thermoelectric properties of the compound by tuning the electronic energy band structure [18,19]. The high temperature thermoelectric transport properties have not been systematically evaluated. To this end, we utilized iodine as an n-type dopant for MoTe2 and studied the phase structure, morphology, and thermoelectric properties of the resulting compounds. The aim of our work is to probe a way of improving the thermoelectric properties of n-type polycrystalline MoTe2 on the basis of synthesis and impurity doping
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Materials Science: Materials in Electronics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
