Preparation and thermoelectric properties of Al-doped ZnO ceramics

Cai, Kefeng; Müller, Eckhard; Drašar, Č.; Mrotzek, Antje

doi:10.1016/s0921-5107(03)00280-0

Cited by 158 publications

(105 citation statements)

References 12 publications

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“…This indicates that solution processes are most likely to reduce the thermal conductivity of ZnO ceramics because they form fine particles in the ceramics. 18) Therefore, in this study, we employed a ''solution combustion synthesis'' (SCS) 19,20) method since it is considered as one of the most simple solution-based combustion synthesis methods. Notably, the chemical energy released from the redox reaction instantaneously heats up the system, and neither additional heating nor special chemicals are required.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties of Solution Combustion Synthesized Al-Doped ZnO

et al. 2008

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Thermoelectric properties of Al-doped ZnO prepared by solution combustion synthesis using urea as fuel and sintered by spark plasma sintering were investigated for developing an energy-and time-saving synthesis method to decrease its thermal conductivity without a significant deterioration in other thermoelectric properties. The desired materials were successfully synthesized and sintered. The thermoelectric properties of the synthesized products subjected to planetary ball milling (PBM) treatment before sintering were compared with those of synthesized products not subjected to PBM treatment; the results showed that the former products had a larger power factor and higher thermal conductivity than the latter products. The thermal conductivity of all as-synthesized products was in the range of 8.3-19.7 WÁm À1 ÁK À1 at room temperature, which was significantly lower than that of the products synthesized by a conventional solid-state reaction method. (Zn 0:99 Al 0:01 )O obtained by PBM had the highest dimensionless figure of merit ZT of 0.050 at 863 K. From these results, it is inferred that solution combustion synthesis is an effective method for synthesizing Al-doped ZnO with relatively low thermal conductivity for high-temperature thermoelectric applications.

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Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties of Solution Combustion Synthesized Al-Doped ZnO

et al. 2008

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“…13 The reduced thermal conductivity can be particularly useful for thermoelectric applications, where the control of thermal conductivity independent from the Seebeck coefficient and electrical conductivity can greatly improve the performance of a material. We reported the Seebeck coefficients and electrical conductivities of the (Zn,Al)O:HQ films in a previous study, and little change was observed in the power factor of the hybrid SL samples compared to ZnO.…”

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confidence: 99%

Efficiently suppressed thermal conductivity in ZnO thin films via periodic introduction of organic layers

et al. 2014

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“…The conductivity was found to increase slowly with measurement temperature. In the solid-state reaction of ZnO and Al 2 O 3 during sintering, there are two most likely reactions, namely, Al 3 þ substitution on Zn 2 þ and Al 3 þ forming the gahnite phase (Cai et al 2003;Bérardan 2010;Singh 2004;Zhan et al 2011). In atmosphere with sufficient oxygen, the reactions can be expressed as:…”

Section: Resultsmentioning

confidence: 99%

“…Aluminum is a common dopant utilized for ZnO, and previous studies have revealed that σ of Al 2 O 3 -modified ZnO can be increased by more than three orders of magnitude (Ohtaki, Tsubota, and Eguchi 1996;Tsubota et al 1997). Electrical conductivity enhancement has been primarily attributed to the Al 3 þ substitution on the Zn 2 þ site resulting in a free electron (Cai et al 2003). However, the doping concentration is restricted due to the limited Al solubility in ZnO with a maximum of 0.3 at.% at 1,400°C (Shirouzu et al 2007).…”

Section: Introductionmentioning

confidence: 99%

“…However, the doping concentration is restricted due to the limited Al solubility in ZnO with a maximum of 0.3 at.% at 1,400°C (Shirouzu et al 2007). Additional Al 2 O 3 forms the secondary phase corresponding to ZnAl 2 O 4 , which has a negative impact on the magnitude of electrical conductivity (Cai et al 2003;. According to phase diagram of the Al 2 O 3 -ZnO system, the reaction between ZnO and Al 2 O 3 varies considerably with temperature, which changes the function of Al in ZnO matrix.…”

Section: Introductionmentioning

confidence: 99%

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Role of Sintering Atmosphere and Synthesis Parameters on Electrical Conductivity of ZnO

Zhao

Wang

Huxtable

et al. 2015

Energy Harvesting and Systems

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ZnO-based compositions are of great interest for high-temperature thermoelectric applications. In this study, n-type Al-doped ZnO was sintered under varying atmospheres and the changes in electrical conductivity along with chemical defects were analyzed. The electrical conductivity of Al-doped ZnO (ZnO-Al) exhibited large variation from 10 −5 to 10 3 S/cm as the sintering atmosphere was changed from air to nitrogen to vacuum. The low oxygen partial pressure assisted Al substitution in ZnO and increased the interstitial Zn, which increased the carrier concentration and improved the electrical conductivity. Using vacuum sintering, the electrical conductivity of ZnO was enhanced as the concentration of Al doping was increased from 1 to 3 at.%. Two sets of starting powders were used for sintering studies, one synthesized through the ball-milling and other through the sol-gel chemical synthesis. It was found that the Al substitution is improved by using chemically synthesized ZnO-Al powders.

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Preparation and thermoelectric properties of Al-doped ZnO ceramics

Cited by 158 publications

References 12 publications

Thermoelectric Properties of Solution Combustion Synthesized Al-Doped ZnO

Thermoelectric Properties of Solution Combustion Synthesized Al-Doped ZnO

Efficiently suppressed thermal conductivity in ZnO thin films via periodic introduction of organic layers

Role of Sintering Atmosphere and Synthesis Parameters on Electrical Conductivity of ZnO

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