“…Similarly, we also demonstrated that adjusting the amount of additives can control the distribution of A site ions, and inhibit nanoinclusion formation, thereby signicantly increasing the thermoelectric power factor. 29 In this work, we seek to understand how the addition of graphene derivatives into the bulk matrix improves the properties of the material. The clear advantages of these additives are their scale and two-dimensional geometry (with lateral dimensions much larger than thickness) which may introduce interesting effects on each of the thermoelectric variables.…”
“…Similarly, we also demonstrated that adjusting the amount of additives can control the distribution of A site ions, and inhibit nanoinclusion formation, thereby signicantly increasing the thermoelectric power factor. 29 In this work, we seek to understand how the addition of graphene derivatives into the bulk matrix improves the properties of the material. The clear advantages of these additives are their scale and two-dimensional geometry (with lateral dimensions much larger than thickness) which may introduce interesting effects on each of the thermoelectric variables.…”
“…The net benefit of the graphite processing environment becomes apparent in the data for maximum power factor (electronic supplementary material, figure S7) increasing, for example, to approximately 1.80 × 10 −3 W m −1 K −2 at 350 K for x = 0.10. This type of increase is reflected in all other samples sintered under graphite, with an average σ S 2 value of 1.0 × 10 −3 W m −1 K −2 for compositions with x ≤ 0.40 from 475 to 975 K. This improvement was due to the significant enhancement of σ dominating the reduction of |S| with carbon burial sintering, together giving some of the highest values reported for SrTiO 3 -based thermoelectrics [16]. Figure 9.Temperature dependencies of ( a ) electrical conductivity, ( b ) Seebeck coefficient, ( c ) total thermal conductivity and ( d ) ZT values of the samples prepared in graphite.…”
Section: Resultsmentioning
confidence: 85%
“…A similar approach was followed by Kovalevsky et al [15], but their work was limited to a low concentration of vacancies. While there have been numerous studies of La doping of SrTiO 3 [16], there have been comparatively few of other lanthanides. One exception is that of Pr substitution by Dehkordi et al [17].…”
Section: Introductionmentioning
confidence: 99%
“…They prepared Sr 1− x Pr x TiO 3 ( x ≤ 0.15) by Spark Plasma Sintering techniques and achieved a high power factor of approximately 1.68 × 10 −3 W m −1 K −2 at 773 K, attributing the enhancement to the formation of Pr-rich grain boundaries. While the ZT value is one very useful screening parameter for candidate materials, the Power Factor is in many ways more useful for indicating the potential of the material to generate power in a device [16].…”
A-site deficient perovskites are among the most important
n
-type thermoelectric oxides. Ceramics of Sr
1−
x
Pr
2
x
/3
□
x
/3
TiO
3
(
x
= 0.1–1.0) were prepared by solid-state reaction at 1700–1723 K using highly reducing atmospheres. Samples with the highest Sr content had a cubic crystal structure
(
P
m
3
¯
m
)
; incorporating Pr with A-site vacancies led to a reduction in symmetry to tetragonal (
I4/mcm
) and then orthorhombic (
Cmmm
) crystal structures. HRTEM showed Pr
2/3
TiO
3
had a layered structure with alternating fully and partially occupied A-sites and a short-range order along the (100) direction. Electrical conductivity was highest in samples of high symmetry (
x
≤ 0.40), where the microstructures featured core-shell and domain structures. This enabled a very high power factor of approximately 1.75 × 10
−3
W m
−1
K
−2
at 425 K. By contrast, at high Pr content, structural distortion led to reduced electron transport; enhanced phonon scattering (from mass contrast, local strain and cation–vacancy ordering) led to reduced, glass-like, thermal conductivity. Carbon burial sintering increased the oxygen deficiency leading to increased carrier concentration, a maximum power factor of approximately 1.80 × 10
−3
W m
−1
K
−2
at 350 K and thermoelectric figure of merit of 0.26 at 865 K. The paper demonstrates the importance of controlling both crystal structure and microstructure to enhance thermoelectric performance.
This article is part of a discussion meeting issue ‘Energy materials for a low carbon future’.
“…Lowest Seebeck coefficient and highest power factor(~ 1000 µV/m. K 2 ) were obtained for the same composition leading to a ZT of 0.37 at 1015 K [32]. To tune the thermal conductivity, substituting Ca and Ba at the A site has resulted in lowering the same [33,34].…”
Sustainable energy sources and energy-harvesting technologies have been researched for decades. Thermoelectric conversion is currently one of the primary foci in this area. Thermoelectric research has been concentrated into two parts-(i) strategies to enhance the efficiency of existing thermoelectric materials and (ii) development of new materials with promising thermoelectric parameters. Although such strategies have led to the improvement of thermoelectric non-oxide-based materials, the limitations possessed by them does not allow to be used at high temperatures. Due to the same reason, oxide-based materials have gained much attention. Here, we discuss about the oxide thermoelectric materials in detail and the effect of texturization on their morphology and transport properties. There is a lot of scope available for such class of materials for high-temperature applications.
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