2018 |
Figueroa-Millon, S; Alvarez-Serrano, I; Berardan, D; Galdámez, A Synthesis and Transport Properties of P-Type Lead-Free Agsnmsbse2tem Thermoelectric Systems Artículo de revista Materials Chemistry and Physics, 211 , pp. 321-328, 2018, ISSN: 0254-0584. Resumen | Enlaces | BibTeX | Etiquetas: agpbmsbte2+m, chemical diffraction, efficiency, electron figure, high hrtem, materials, merit, microscopy nanostructured performance, synthesis, thermoelectric thermoelectrics, transmission x-ray x=0 @article{RN400, title = {Synthesis and Transport Properties of P-Type Lead-Free Agsnmsbse2tem Thermoelectric Systems}, author = { S. Figueroa-Millon and I. Alvarez-Serrano and D. Berardan and A. Gald\'{a}mez}, url = {/brokenurl#<Go to ISI>://WOS:000430774300040}, doi = {10.1016/j.matchemphys.2018.02.047}, issn = {0254-0584}, year = {2018}, date = {2018-01-01}, journal = {Materials Chemistry and Physics}, volume = {211}, pages = {321-328}, publisher = {2018 Elsevier B.V.}, abstract = {We report the synthesis, characterization and thermoelectric properties of lead-free AgSnmSbSe2Tem (m = 2 and 10) systems. Powder X-ray diffraction patterns and Rietveld refinement results were consistent with phases belonging to the Pm (3) over barm space group. The microstructures and morphologies of these systems were investigated using scanning electron microcopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Parallelepiped bars for transport measurements were prepared using two methods: the classical method (CM) from melted samples and the spark plasma sintering (SPS). The AgSnmSbSe2Tem (m = 2 and 10) systems exhibited typical degenerate semiconductor behavior, with a carrier concentration of approximately +10(21) cm(-3). We determined that the Seebeck coefficient can be substantially increased from approximately +40 V K-1 (CM) to +70 mu V K-1 (SPS) in AgSn2SbSe2Te2 at room temperature. Consequently, the power factor (S(2)cr) was similar to 22 W cm(-1) K-2. On the basis of the electrical and thermal transport properties, ZT values of similar to 0.10 were obtained at room temperature.}, keywords = {agpbmsbte2+m, chemical diffraction, efficiency, electron figure, high hrtem, materials, merit, microscopy nanostructured performance, synthesis, thermoelectric thermoelectrics, transmission x-ray x=0}, pubstate = {published}, tppubtype = {article} } We report the synthesis, characterization and thermoelectric properties of lead-free AgSnmSbSe2Tem (m = 2 and 10) systems. Powder X-ray diffraction patterns and Rietveld refinement results were consistent with phases belonging to the Pm (3) over barm space group. The microstructures and morphologies of these systems were investigated using scanning electron microcopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Parallelepiped bars for transport measurements were prepared using two methods: the classical method (CM) from melted samples and the spark plasma sintering (SPS). The AgSnmSbSe2Tem (m = 2 and 10) systems exhibited typical degenerate semiconductor behavior, with a carrier concentration of approximately +10(21) cm(-3). We determined that the Seebeck coefficient can be substantially increased from approximately +40 V K-1 (CM) to +70 mu V K-1 (SPS) in AgSn2SbSe2Te2 at room temperature. Consequently, the power factor (S(2)cr) was similar to 22 W cm(-1) K-2. On the basis of the electrical and thermal transport properties, ZT values of similar to 0.10 were obtained at room temperature. |
2017 |
Paredes-Gil, K; Mendizabal, F; Paez-Hernandez, D; Arratia-Perez, R Computational Materials Science, 126 , pp. 514-527, 2017, ISSN: 0927-0256. Resumen | Enlaces | BibTeX | Etiquetas: computational density-functional dye, efficiency, electrochemistry, energy-levels, excited-states, families, light-harvesting model, n-annulated n719 perylene properties, related solar spectroscopic studies, theory, tio2 zn-porphyrin @article{RN359, title = {Electronic Structure and Optical Properties Calculation of Zn-Porphyrin with N-Annulated Perylene Adsorbed on Tio2 Model for Dye-Sensitized Solar Cell Applications: A Dft/Td-Dft Study}, author = { K. Paredes-Gil and F. Mendizabal and D. Paez-Hernandez and R. Arratia-Perez}, url = {/brokenurl#<Go to ISI>://WOS:000389089900058}, doi = {10.1016/j.commatsci.2016.09.042}, issn = {0927-0256}, year = {2017}, date = {2017-01-01}, journal = {Computational Materials Science}, volume = {126}, pages = {514-527}, publisher = {2016 Elsevier B.V.}, abstract = {The current work scrutinizes the chemical behavior of a set of promissory dyes, the Zn-porphyrins with N-annulated Perylene, WW3m-WW8m, within the most important steps in the solar cell: photoexcitation, electron injection and dye regeneration. The photoexcitation step was studied through TD-DFT frame-work, finding that the most intense band in WW4m, WW6m-WW8m corresponds to the electronic transition of the frontier orbitals HOMO-LUMO. Among these, WW6m is highlighted, because the electronic density of the LUMO is localized over the anchoring group. Therefore, the presence of two ethynylene spacers in the WW6m porphyrin originate an enhancement in the light absorption. On the other hand, we analyze the electron injection modelling two (mono and bidentate) adsorbing modes in WW3m @Ti0(2)-WW8m @TiO2 using DFT (B3LYP+D3) calculations. Adsorption energies. show that WW3m @Ti0(2)-WW8m @TiO2 are coordinated in bidentate mode. In this sense, to analyze the density of states (DOS) we found that WW6m @TiO2 present the narrowest band gap (1.53 eV), promoting an easy electron injection, which could explain the origin of the highest overall efficiency of the solar cell for this porphyrin. Finally, dye regeneration, was studied through the free energy associated, Delta G(regen,) the values are between -6.61 and -6.93 eV for WW3m @Ti02-WW8m @TiO2 showing that this step is spontaneous and similar in all porphyrins.}, keywords = {computational density-functional dye, efficiency, electrochemistry, energy-levels, excited-states, families, light-harvesting model, n-annulated n719 perylene properties, related solar spectroscopic studies, theory, tio2 zn-porphyrin}, pubstate = {published}, tppubtype = {article} } The current work scrutinizes the chemical behavior of a set of promissory dyes, the Zn-porphyrins with N-annulated Perylene, WW3m-WW8m, within the most important steps in the solar cell: photoexcitation, electron injection and dye regeneration. The photoexcitation step was studied through TD-DFT frame-work, finding that the most intense band in WW4m, WW6m-WW8m corresponds to the electronic transition of the frontier orbitals HOMO-LUMO. Among these, WW6m is highlighted, because the electronic density of the LUMO is localized over the anchoring group. Therefore, the presence of two ethynylene spacers in the WW6m porphyrin originate an enhancement in the light absorption. On the other hand, we analyze the electron injection modelling two (mono and bidentate) adsorbing modes in WW3m @Ti0(2)-WW8m @TiO2 using DFT (B3LYP+D3) calculations. Adsorption energies. show that WW3m @Ti0(2)-WW8m @TiO2 are coordinated in bidentate mode. In this sense, to analyze the density of states (DOS) we found that WW6m @TiO2 present the narrowest band gap (1.53 eV), promoting an easy electron injection, which could explain the origin of the highest overall efficiency of the solar cell for this porphyrin. Finally, dye regeneration, was studied through the free energy associated, Delta G(regen,) the values are between -6.61 and -6.93 eV for WW3m @Ti02-WW8m @TiO2 showing that this step is spontaneous and similar in all porphyrins. |
2018 |
Synthesis and Transport Properties of P-Type Lead-Free Agsnmsbse2tem Thermoelectric Systems Artículo de revista Materials Chemistry and Physics, 211 , pp. 321-328, 2018, ISSN: 0254-0584. |
2017 |
Computational Materials Science, 126 , pp. 514-527, 2017, ISSN: 0927-0256. |