Reinvestigation Thermoelectric Properties of CuAlO2

Ruttanapun, Chesta; Kosalwat, Wattana; Rudradawong, Chalermpol; Jindajitawat, Phumin; Buranasiri, Prathan; Naenkieng, Daengdesh; Boonyopakorn, Narongchai; Harnwunggmoung, Adul; Thowladda, Warawoot; Neeyakorn, Worakarn; Thanachayanont, Chanchana; Charoenphakdee, Anek; Wichainchai, Aree

doi:10.1016/j.egypro.2014.07.132

Cited by 22 publications

(12 citation statements)

References 16 publications

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“…The negative slope gives additional support to p-type conductivity. The N A value should give a thermoelectrical power (S) of *800 lV K -1 , compatible with previous works [47,48]:…”

Section: Photoelectrochemical Propertiesmentioning

confidence: 65%

Sol–gel synthesis and characterization of the delafossite CuAlO2

Benreguia

Barnabé

Trari

2015

J Sol-Gel Sci Technol

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Nanocrystalline CuAlO 2 is synthesized by solgel method using ethylene glycol as solvent. The stages of formation are followed by thermal analysis. The X-ray diffraction pattern of the powder heat-treated at 1100°C shows a single phase, indexed in a rhombohedral symmetry (R 3 m). The apparent crystallite size (57 ± 8 nm) is determined from the Williamson-Hall plot. The direct optical transition (=3.69 eV), evaluated from the diffuse reflectance spectrum, is attributed to the charge transfer (O 2-: 2p ? Cu ? : 4s). The oxide is p-type semiconductor, and the conduction occurs predominantly by small polaron hopping between mixed valences Cu 2?/? , due to oxygen insertion in the layered crystal. The photoelectrochemical characterization gives a flat band of 0.20 V SCE and a hole density of 1.13 9 10 18 cm -3 . The semicircle centered on the real axis, in the electrochemical impedance spectroscopy (EIS), is due to the absence of constant phase element with a pure capacitive behavior. The straight line at 35°at low frequencies is attributed to the diffusion in the layered structure. Graphical Abstract Temperature dependence of the electrical conductivity for CuAlO 2 synthesized by sol-gel method. Inset: the variable range hopping at low temperatures. The sol-gel method has been successfully employed for the preparation of CuAlO 2 . The thermal variation of the conductivity indicates a semiconducting behavior which is frequency independent. At low temperature, a variable range hopping involves electrons jump over large distances according to the Mott law r ¼ r 0 exp T 0 T À Á 0:25 .

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“…The negative slope gives additional support to p-type conductivity. The N A value should give a thermoelectrical power (S) of *800 lV K -1 , compatible with previous works [47,48]:…”

Section: Photoelectrochemical Propertiesmentioning

confidence: 65%

Sol–gel synthesis and characterization of the delafossite CuAlO2

Benreguia

Barnabé

Trari

2015

J Sol-Gel Sci Technol

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“…Among transparent materials ( E g >3 eV), p-type γ-CuI thin film exhibits a 1,000 times improvement of the ZT compared to those of any other p-type material such as CuAlO 2 (ref. 12 ), and almost twice compared to those of n-type materials, such as Al-doped ZnO 9 and ITO 10 . Nevertheless, the thermoelectric properties of CuI can be further improved: for example, it is possible to enhance the ZT of the CuI by increasing its hole density, which is limited to around 1 × 10 20 cm −3 in this work due to unintentional doping.…”

Section: Discussionmentioning

confidence: 98%

“…On the other hand, p-type TCs usually exhibit poor electrical conductivities σ , which are several orders of magnitude smaller than those of n-type TCs, leading to poor thermoelectric performance at room temperature, for example, ZT ∼0.001 for CuAlO 2 (ref. 12 ) and ZT ∼0.002 for CuCrO 2 (ref. 13 ).…”

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confidence: 99%

Transparent flexible thermoelectric material based on non-toxic earth-abundant p-type copper iodide thin film

et al. 2017

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Thermoelectric devices that are flexible and optically transparent hold unique promise for future electronics. However, development of invisible thermoelectric elements is hindered by the lack of p-type transparent thermoelectric materials. Here we present the superior room-temperature thermoelectric performance of p-type transparent copper iodide (CuI) thin films. Large Seebeck coefficients and power factors of the obtained CuI thin films are analysed based on a single-band model. The low-thermal conductivity of the CuI films is attributed to a combined effect of the heavy element iodine and strong phonon scattering. Accordingly, we achieve a large thermoelectric figure of merit of ZT=0.21 at 300 K for the CuI films, which is three orders of magnitude higher compared with state-of-the-art p-type transparent materials. A transparent and flexible CuI-based thermoelectric element is demonstrated. Our findings open a path for multifunctional technologies combing transparent electronics, flexible electronics and thermoelectricity.

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“…[21][22][23][24] Figure 2 presents the results of the X-ray diffraction. The structure of the alumina range in the impregnated samples was identified, as well as slight diffraction corresponding to the copper oxide (CuO), [25][26][27][28][29][30][31] see Figure 2a. Meanwhile, the samples synthesized by sol-gel exhibited the typical diffraction of the boehmite structure, but not those of the copper oxide, instead, the formation of CuAlO 2 was favored ( Figure 2b).…”

Section: Resultsmentioning

confidence: 99%

Effect of the CuAl₂O₄and CuAlO₂Phases in Catalytic Wet Air Oxidation of ETBE and TAME using CuO/γ‐Al₂O₃catalysts

et al. 2019

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This paper studies Cu/Al 2 O 3 catalysts, synthesized in two ways: copper deposit in the synthesis of alumina (sol gel) and incipient impregnation stabilized at 400 °C. The materials were characterized by X‐ray diffraction studies, nitrogen physisorption, temperature programmed reduction of H 2 , dehydration of isopropanol, scanning electronic microscopy, transmission electronic microscopy, which were evaluated in the liquid phase oxidation reaction of ethyl tert‐butyl ether and tert‐amyl methyl ether. The formation of CuAl 2 O 4 and CuAlO 2 in the samples synthesized by sol gel, led to a modification of the texture, thus resulting in an expansion of the specific area of the materials. CuAl 2 O 4 and CuAlO 2 have been identified by DRX from a content of 10 % Copper, the first showed the highest intensity with this technique. In the same way, these species favor the presence of Lewis acid sites; this is reflected in the materials with (Di‐isopropyl Ether) DIPE of 96.7 % and 91.1 % for the samples SAlCu5 and SAlCu15 respectively. The catalytic activity of the materials prepared by sol gel is in the function of the number of surface acid sites, the smaller particle size of the Cu and the surface of the contact, in the case of the ETBE meanwhile for TAME the activity was based mainly on the strength of the present acid sites. With impregnated materials, the activity is attributed to the smaller particle size of the Cu and the greater strength of the surface acid sites in the solid. The formation of spinel species inhibits the leaching phenomenon in the reaction milieu.

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Reinvestigation Thermoelectric Properties of CuAlO2

Cited by 22 publications

References 16 publications

Sol–gel synthesis and characterization of the delafossite CuAlO2

Sol–gel synthesis and characterization of the delafossite CuAlO2

Transparent flexible thermoelectric material based on non-toxic earth-abundant p-type copper iodide thin film

Effect of the CuAl₂O₄and CuAlO₂Phases in Catalytic Wet Air Oxidation of ETBE and TAME using CuO/γ‐Al₂O₃catalysts

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Reinvestigation Thermoelectric Properties of CuAlO2

Cited by 22 publications

References 16 publications

Sol–gel synthesis and characterization of the delafossite CuAlO2

Sol–gel synthesis and characterization of the delafossite CuAlO2

Transparent flexible thermoelectric material based on non-toxic earth-abundant p-type copper iodide thin film

Effect of the CuAl2O4and CuAlO2Phases in Catalytic Wet Air Oxidation of ETBE and TAME using CuO/γ‐Al2O3catalysts

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Effect of the CuAl₂O₄and CuAlO₂Phases in Catalytic Wet Air Oxidation of ETBE and TAME using CuO/γ‐Al₂O₃catalysts