Enhanced average thermoelectric figure of merit of n-type PbTe1−xIx–MgTe. Issue 40 (11th August 2015)

• Record Type: Journal Article
• Authors: Jood, Priyanka; Ohta, Michihiro; Kunii, Masaru; Hu, Xiaokai; Nishiate, Hirotaka; Yamamoto, Atsushi; Kanatzidis, Mercouri G.
• Is Part Of: Journal of materials chemistry. Volume 3:Issue 40(2015)
• Page Start: 10401
• Page End: 10408
• Publication Date: 2015-08-11
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c5tc01652e
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : The average thermoelectric figure of merit ZT of n-type PbTe1− x I x –MgTe is successfully enhanced through nano and meso structuring. Abstract : The thermoelectric properties of sintered samples of n-type PbTe1− x I x – y MgTe ( x = 0.0012–0.006; y = 0 and 1%) were investigated over the temperature range of 300 K to 900 K. Scanning electron microscopy revealed two different length scales of grains in samples with higher I and MgTe contents, while a homogenous microstructure for samples with a lower dopant content. Transmission electron microscopy revealed ubiquitous spherical nanoprecipitates in PbTe1− x I x with MgTe and nanoscale disk like precipitates in both, PbTe1− x I x with and without MgTe. The nanostructured PbTe showed higher Seebeck coefficients than expected values. We also observed a slower rate of increase in the electrical resistivity with rising temperature in PbTe1− x I x – y MgTe below ∼550 K, leading to a higher thermoelectric power factor. The nanostructures and mixed microstructures scatter phonons, reducing the lattice thermal conductivity as low as 0.4 W K −1 m −1 at 600 K. A high ZT of 1.2 at 700 K was achieved as well as a high average ZT of 0.8 was observed in PbTe0.996 I0.004 –1 mol% MgTe for a cold-side temperature of 303 K and a hot-side temperature of 873 K.