scholarly journals Crystal structure and thermoelectric properties of Sr–Mo substituted CaMnO3: a combined experimental and computational study

2015 ◽  
Vol 3 (47) ◽  
pp. 12245-12259 ◽  
Author(s):  
D. Srivastava ◽  
F. Azough ◽  
R. Freer ◽  
E. Combe ◽  
R. Funahashi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Thermal Transport ◽  
Computational Study ◽  
Domain Boundaries ◽  
Co Doped

Experimental and modelling investigation of Sr/Mo (co-)doped CaMnO3 highlighted the role of Mn3+ and presence of domain boundaries in thermal transport and thermoelectric properties.

scholarly journals Thermoelectric Properties of Bi2Te3: CuI and the Effect of Its Doping with Pb Atoms

2017 ◽  
Author(s):  
Mi-Kyung Han ◽  
Yingshi Jin ◽  
Da-Hee Lee ◽  
Sung-Jin Kim
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Thermal Transport ◽  
Co Doping ◽  
Thermal Transport Properties ◽  
Co Doped

In order to understand the effect of Pb-CuI co-doping on the thermoelectric performance of Bi2Te3, n-type Bi2Te3 co-doped with x at% CuI and 1/2x at% Pb (x = 0, 0.01, 0.03, 0.05, 0.07, and 0.10) were prepared via high temperature solid state reaction and consolidated using spark plasma sintering. Electron and thermal transport properties, i.e., electrical conductivity, carrier concentration, Hall mobility, Seebeck coefficient, and thermal conductivity, of CuI-Pb co-doped Bi2Te3 were measured in the temperature range from 300 K to 523 K and compared to corresponding x% of CuI-doped Bi2Te3 and undoped Bi2Te3. The addition of a small amount of Pb significantly decreased the carrier concentration, which could be attributed to the holes from Pb atoms, thus the CuI-Pb co-doped samples show a lower electrical conductivity and a higher Seebeck coefficient compared to CuI-doped samples with similar x values. The incorporation of Pb into CuI-doped Bi2Te3 rarely changed the power factor because of the trade-off relationship between the electrical conductivity and the Seebeck coefficient. The total thermal conductivity(κtot) of co-doped samples (κtot ~1.4 W/m∙K at 300 K) is slightly lower than that of 1% CuI-doped Bi2Te3 (κtot~1.5 W/m∙K at 300 K) and undoped Bi2Te3 (κtot ~1.6 W/m∙K at 300 K) due to the alloy scattering. The 1% CuI-Pb co-doped Bi2Te3 sample shows the highest ZT value of 0.96 at 370 K. All data on electrical and thermal transport properties suggest that the thermoelectric properties of Bi2Te3 and its operating temperature can be controlled by co-doping.

Sn1−xSe thin films with low thermal conductivity: role of stoichiometric deviation in thermal transport

2018 ◽  
Vol 6 (37) ◽  
pp. 10083-10087 ◽  
Author(s):  
Giuk Jeong ◽  
Yoon Hwan Jaung ◽  
Jekyung Kim ◽  
Jae Yong Song ◽  
Byungha Shin
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Thermal Transport ◽  
Low Thermal Conductivity ◽  
Tin Selenide ◽  
Polycrystalline Thin Films

Tin selenide (Sn1−xSe) polycrystalline thin films were prepared by thermal co-evaporation, and the thermoelectric properties of the Sn1−xSe thin films were investigated.

Predicted low thermal conductivities in antimony films and the role of chemical functionalization

2016 ◽  
Vol 18 (43) ◽  
pp. 30061-30067 ◽  
Author(s):  
Tian Zhang ◽  
Yuan-Yuan Qi ◽  
Xiang-Rong Chen ◽  
Ling-Cang Cai
Keyword(s):  
Crystal Structure ◽  
Thermal Transport ◽  
Effective Means ◽  
Two Dimensional ◽  
Chemical Functionalization ◽  
Thermal Conductivities

Chemical functionalization is an effective means of tuning the electronic and crystal structure of a two-dimensional material, but very little is known regarding the correlation between thermal transport and chemical functionalization.

scholarly journals Role of Chemistry and Crystal Structure on the Electronic Defect States in Cs-Based Halide Perovskites

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1032
Author(s):  
Anirban Naskar ◽  
Rabi Khanal ◽  
Samrat Choudhury
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Covalent Bond ◽  
Density Functional Theory Calculations ◽  
Antisite Defect ◽  
Defect States ◽  
Functional Theory ◽  
Electronic Defect ◽  
Constituent Elements

The electronic structure of a series perovskites ABX3 (A = Cs; B = Ca, Sr, and Ba; X = F, Cl, Br, and I) in the presence and absence of antisite defect XB were systematically investigated based on density-functional-theory calculations. Both cubic and orthorhombic perovskites were considered. It was observed that for certain perovskite compositions and crystal structure, presence of antisite point defect leads to the formation of electronic defect state(s) within the band gap. We showed that both the type of electronic defect states and their individual energy level location within the bandgap can be predicted based on easily available intrinsic properties of the constituent elements, such as the bond-dissociation energy of the B–X and X–X bond, the X–X covalent bond length, and the atomic size of halide (X) as well as structural characteristic such as B–X–B bond angle. Overall, this work provides a science-based generic principle to design the electronic states within the band structure in Cs-based perovskites in presence of point defects such as antisite defect.

scholarly journals The Activating Effect of Strong Acid for Pd-Catalyzed Directed C–H Activation by Concerted Metalation-Deprotonation Mechanism

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4083
Author(s):  
Heming Jiang ◽  
Tian-Yu Sun
Keyword(s):  
Activation Energy ◽  
Dft Calculations ◽  
Energy Barrier ◽  
Computational Study ◽  
Strong Acid ◽  
Activation Energy Barrier ◽  
Pd Catalysts ◽  
Acid Ligand ◽  
Strong Acids

A computational study on the origin of the activating effect for Pd-catalyzed directed C–H activation by the concerted metalation-deprotonation (CMD) mechanism is conducted. DFT calculations indicate that strong acids can make Pd catalysts coordinate with directing groups (DGs) of the substrates more strongly and lower the C–H activation energy barrier. For the CMD mechanism, the electrophilicity of the Pd center and the basicity of the corresponding acid ligand for deprotonating the C–H bond are vital to the overall C–H activation energy barrier. Furthermore, this rule might disclose the role of some additives for C–H activation.

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