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Preparation and study of the thermoelectric properties of nanocrystalline Sn 1− x Ta x O 2 (0 ≤ x ≤ 0.04)
Author(s) -
Vo Thi Thanh Xuan,
Le Thi Ngoc Ha,
Pham Quoc Nghi,
Byl Céline,
Dragoe Diana,
BarthésLabrousse MarieGeneviève,
Bérardan David,
Dragoe Nita
Publication year - 2015
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201532281
Subject(s) - spark plasma sintering , nanocrystalline material , materials science , analytical chemistry (journal) , thermoelectric effect , x ray photoelectron spectroscopy , sintering , carbon fibers , thermal conductivity , pellets , seebeck coefficient , electrical resistivity and conductivity , nuclear chemistry , chemical engineering , metallurgy , nanotechnology , chemistry , composite material , composite number , physics , chromatography , engineering , thermodynamics , electrical engineering
Sn 1– x Ta x O 2 (0 ≤ x nominal ≤ 0.04) nanoparticles, smaller than 10 nm, were synthesized by co‐precipitation method. The solubility limit of Ta (about 0.8% mol) was carefully studied by combination of XRD, SEM, and ICP analysis. The obtained powders were sintered by using the spark plasma sintering (SPS) technique, leading to dense pellets (∼95–97% density), composed of 50–70 nm grains. XPS results suggest that no Sn 2+ is present in our samples and that the carbon contamination as well as oxygen vacancies, issues from SPS, are not completely removed with a post‐SPS heat treatment at 873 K. However, this small carbon contamination does not significantly influence the electrical properties. Thermoelectric properties were investigated and the best composition was found to be Sn 0.99 Ta 0.01 O 2 ( x = 0.01), with ρ = 4 × 10 −3 Ωcm, S = −46 μVK −1 , and κ ∼ 7 WK −1 m −1 , at room temperature. This low thermal conductivity, as compared to those of micro‐sized SnO 2 ‐based materials in the literature, is explained by the nanocrystalline character of the samples.