Year: 2015
Type: article
Abstract: ABSTRACTWe investigated codoping of Ba8AlySi46−y clathrate system with gallium and phosphorus, nominal composition Ba8Al16GaxSi30−2xPx (x = 0, 0.5, 0.6, 0.75, 1.0, 1.5, 2.0), and their thermoelectric properties. Samples were prepared by combining arc melting and spark plasma sintering methods. The x-ray diffraction, scanning electron microscopy, and energy dispersive analysis of x-ray studies revealed that the total content of Al and Ga increased to 15.66 (at x = 2.0), which was higher than the solubility limit (approximately y~15) of aluminum in Ba8AlySi46−y system. The carrier concentration of samples decreased from ~1 × 1021 cm−3 (y = 15), which was the lowest value in Ba8AlySi46−y system so far, to ~6 × 1020 cm−3. According to the decrease in carrier concentration, the Seebeck coefficient increased while the electrical conductivity decreased. The thermal conductivity decreased monotonically with x. The thermoelectric figure of merit ZT was improved to about 0.47 at 900 K, which was higher than the maximum value for Ba8AlySi46−y system.
DOI: 10.2497/jjspm.62.194
Authors: Hiroaki ANNO, Takahiro UEDA, Hironori SAKUMA
Institutions: Tokyo University of Science, Sanyo-Onoda City University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W2334949987