Improved thermoelectric properties of layered Ti1−xNbxS2−ySey solid solutions. Issue 11 (7th July 2020)

• Record Type: Journal Article
• Authors: 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, Mi‐Kyung; Kim, Sung‐Jin
• Is Part Of: Journal of the American Ceramic Society. Volume 103:Issue 11(2020)
• Page Start: 6289
• Page End: 6297
• Publication Date: 2020-07-07
• Subjects: electrical conductivity -- low temperature -- thermoelectric properties; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.17342
• Languages: English
• ISSNs: 0002-7820

Abstract

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 Ti1− x Nb x S2− y Se y solid solutions was found. The Fermi energy EF2D was estimated using the temperature dependences of Seebeck coefficient. The relationship between the Fermi energy EF 2 D and figure of merit ZT was established. The effect of sintering on parameters σ ( T ), S ( T ), charge carrier concentration ( n2D ), mobility ( µ ), and thermal conductivity ( k ) was found. The optimal value of Fermi energy EF2D in terms of figure of merit ZT = 0.31 at room temperature ( T = 300 K) was found for Ti0.98 Nb0.02 S1.3 Se0.7 sample sintered at 600°C.