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Improved thermoelectric properties of layered Ti 1− x Nb x S 2− y Se y solid solutions
Author(s) -
Romanenko Anatoly I.,
Yakovleva Galina E.,
Fedorov Vladimir E.,
Artemkina Sofya B.,
Yu. Ledneva Alexandra,
Zhdanov Kamil R.,
Kuchumov Boris M.,
Kuznetsov Vitalii A.,
Wang Hongchao,
Singh Sanjai,
Saini Shivani,
Han MiKyung,
Kim SungJin
Publication year - 2020
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17342
Subject(s) - seebeck coefficient , thermoelectric effect , materials science , sintering , electrical resistivity and conductivity , atmospheric temperature range , condensed matter physics , fermi level , thermoelectric materials , thermal conductivity , figure of merit , analytical chemistry (journal) , crystallite , mineralogy , thermodynamics , metallurgy , electron , chemistry , physics , composite material , optoelectronics , chromatography , quantum mechanics
Abstract The thermoelectric properties of a series of the polycrystalline samples of titanium dichalcogenides with partial substitution of Ti for Nb and S for Se were investigated. It was found that sintering of the samples improved the thermoelectric efficiency ( ZT ), and the maximum ZT was achieved at sintering temperature of 600°C. A further increase in the sintering temperature (850°C and 950°C) led to the recrystallization of the samples, as a result, the Seebeck coefficient sharply decreased and electrical conductivity dramatically increased. The temperature dependences of electrical conductivity σ ( T ) in the temperature range from 4.2 to 300 K and Seebeck coefficient S ( T ) in the temperature range from 77 to 300 K were investigated in order to determine the nature of the observed improvements in thermoelectric properties due to double substitutions and sintering. Two‐dimensionalization of electron transport properties of Ti 1− x Nb x S 2− y Se y solid solutions was found. The Fermi energy E F2D was estimated using the temperature dependences of Seebeck coefficient. The relationship between the Fermi energy E F 2 D and figure of merit ZT was established. The effect of sintering on parameters σ ( T ), S ( T ), charge carrier concentration ( n 2D ), mobility ( µ ), and thermal conductivity ( k ) was found. The optimal value of Fermi energy E F2D in terms of figure of merit ZT = 0.31 at room temperature ( T = 300 K) was found for Ti 0.98 Nb 0.02 S 1.3 Se 0.7 sample sintered at 600°C.