Pub Date : 2023-09-20DOI: 10.15251/cl.2023.208.619
M. L. Han, Y. Hu
Hydrostatic pressure is an effective tool that can give rise to novel crystal structures and physical properties. In this paper, we perform the first-principles calculation based on density-functional theory (DFT) to study the structural, electronic, elastic, and optical properties of chalcogenide perovskite SrZrS3 under pressure. The results indicated that both the lattice constant and cell volume decrease with the increase of pressure, which are matched well with available previous values. The obtained elastic constants reveal the SrZrS3 is mechanically stable between 0 and 15 GPa. Additionally, the main features of the valence and conduction bands have been analyzed from the total and partial density of states. The complex dielectric function, refractive index, absorption coefficient, reflectivity, and the extinction coefficient are also calculated and analyzed. According to our work, we found that the optical properties of SrZrS3 undergo a red shift with increasing pressure.
{"title":"Structural, electronic, elastic, and optical properties of chalcogenide perovskite SrZrS3 under ambient and high-pressure conditions","authors":"M. L. Han, Y. Hu","doi":"10.15251/cl.2023.208.619","DOIUrl":"https://doi.org/10.15251/cl.2023.208.619","url":null,"abstract":"Hydrostatic pressure is an effective tool that can give rise to novel crystal structures and physical properties. In this paper, we perform the first-principles calculation based on density-functional theory (DFT) to study the structural, electronic, elastic, and optical properties of chalcogenide perovskite SrZrS3 under pressure. The results indicated that both the lattice constant and cell volume decrease with the increase of pressure, which are matched well with available previous values. The obtained elastic constants reveal the SrZrS3 is mechanically stable between 0 and 15 GPa. Additionally, the main features of the valence and conduction bands have been analyzed from the total and partial density of states. The complex dielectric function, refractive index, absorption coefficient, reflectivity, and the extinction coefficient are also calculated and analyzed. According to our work, we found that the optical properties of SrZrS3 undergo a red shift with increasing pressure.","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136375025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-20DOI: 10.15251/cl.2023.209.639
L. Yang, X. Q. Yuan, R. Y. Liu, R. X. Song, Q. W. Wang, W. Liang
In this paper, we report a facile method for the synthesis of MoS2 nanosheet/ MoS2 nanowire homostructures by growing MoS2 nanosheets on the surface of MoS2 nanowires. Benefiting from the uniform coating of MoS2 nanosheets on the surface of MoS2 nanowires, the MoS2 nanosheet/ MoS2 nanowire homostructures highly expose their electrocatalytic active edge sites and exhibit an enhanced electrocatalytic performance. It demonstrates a low overpotential of 107 mV at 10 mA/cm2 and a small Tafel slope of 64 mV/dec in 0.5 M H2SO4. This work provides an inspiration for the design of efficient electrocatalysts with no stacking and aggregation structure.
本文报道了一种在MoS2纳米线表面生长MoS2纳米片的简单方法来合成MoS2纳米片/ MoS2纳米线同质结构。由于在MoS2纳米线表面均匀地涂覆了MoS2纳米片，MoS2纳米片/ MoS2纳米线的同质结构高度暴露了其电催化活性边缘位点，并表现出增强的电催化性能。它在10 mA/cm2下的过电位为107 mV，在0.5 M H2SO4中，塔菲尔斜率很小，为64 mV/dec。本研究为设计无堆积、无聚集结构的高效电催化剂提供了启示。
{"title":"Rational design of MoS2 nanosheet/ MoS2 nanowire homostructures and their enhanced hydrogen evolution reaction","authors":"L. Yang, X. Q. Yuan, R. Y. Liu, R. X. Song, Q. W. Wang, W. Liang","doi":"10.15251/cl.2023.209.639","DOIUrl":"https://doi.org/10.15251/cl.2023.209.639","url":null,"abstract":"In this paper, we report a facile method for the synthesis of MoS2 nanosheet/ MoS2 nanowire homostructures by growing MoS2 nanosheets on the surface of MoS2 nanowires. Benefiting from the uniform coating of MoS2 nanosheets on the surface of MoS2 nanowires, the MoS2 nanosheet/ MoS2 nanowire homostructures highly expose their electrocatalytic active edge sites and exhibit an enhanced electrocatalytic performance. It demonstrates a low overpotential of 107 mV at 10 mA/cm2 and a small Tafel slope of 64 mV/dec in 0.5 M H2SO4. This work provides an inspiration for the design of efficient electrocatalysts with no stacking and aggregation structure.","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136377808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-20DOI: 10.15251/cl.2023.209.629
N. S. Khairuddin, M. Z. Mohd Yusoff, H. Hussin
In this study, we used the PC1D simulator to demonstrate the performance analysis of a solar cell model based on gallium nitride (GaN). It has been discovered that when the layer thickness of the GaN substrate grows, the efficiency of solar cells decreases. This was found by comparing the doping concentration and layer thickness on the GaN and silicon substrates. As the thickness of the p-doping Si layer rises, cell efficiency increases just modestly. The optimal doping concentrations for GaN and p-silicon are 1x1018 cm-3 and 1x1017 cm-3 , respectively. In compared to other designs, GaN/p-silicon solar cells have the highest efficiency of 25.26%.
{"title":"The effects of thickness and doping concentration on the solar efficiency of GaN/p-Si based solar cells","authors":"N. S. Khairuddin, M. Z. Mohd Yusoff, H. Hussin","doi":"10.15251/cl.2023.209.629","DOIUrl":"https://doi.org/10.15251/cl.2023.209.629","url":null,"abstract":"In this study, we used the PC1D simulator to demonstrate the performance analysis of a solar cell model based on gallium nitride (GaN). It has been discovered that when the layer thickness of the GaN substrate grows, the efficiency of solar cells decreases. This was found by comparing the doping concentration and layer thickness on the GaN and silicon substrates. As the thickness of the p-doping Si layer rises, cell efficiency increases just modestly. The optimal doping concentrations for GaN and p-silicon are 1x1018 cm-3 and 1x1017 cm-3 , respectively. In compared to other designs, GaN/p-silicon solar cells have the highest efficiency of 25.26%.","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136375035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-20DOI: 10.15251/cl.2023.208.609
Y. Benkrima, D. Belfennache, R. Yekhlef, A. M. Ghaleb
Our calculations have been done using the density functional theory (DFT). In fact, we were able to find the optical and structural properties of CdSe compound of cubic phase by using the previously mentioned theory. The pseudo-potential linearised augmented plane wave (PP-LAPW) method is applied to solve the Kuhn-Sham equations. The results are obtained using Generalized Gradient Approximation according to the scheme described by Perdew-Burke-Ernzerhof (GGA-PBE) as a types of exchange-correlation. Convergence of energy and charge has been verified, this is for the study of properties basic state of the compound. It was found that the calculated initial cell constants at equilibrium are very close to previous theoretical and experimental works. The electronic properties of the energy band structure and the total density of states confirmed that the CdSe compound has a direct energy gap estimated at 1.52 eV, which is very close to the previous applied results. The general results of the calculated optical properties including the imaginary part of the dielectric constant, absorption coefficient, reflectivity, optical conductance, refractive index, and extinction coefficient of cubic phase CdSe under the imposed conditions are discussed and compared with previous works. Through our results, new and important optical properties of the compound were highlighted, and then determine the areas of its use in the appropriate technological industries.
{"title":"First-principle investigations of structural and optical properties of CdSe","authors":"Y. Benkrima, D. Belfennache, R. Yekhlef, A. M. Ghaleb","doi":"10.15251/cl.2023.208.609","DOIUrl":"https://doi.org/10.15251/cl.2023.208.609","url":null,"abstract":"Our calculations have been done using the density functional theory (DFT). In fact, we were able to find the optical and structural properties of CdSe compound of cubic phase by using the previously mentioned theory. The pseudo-potential linearised augmented plane wave (PP-LAPW) method is applied to solve the Kuhn-Sham equations. The results are obtained using Generalized Gradient Approximation according to the scheme described by Perdew-Burke-Ernzerhof (GGA-PBE) as a types of exchange-correlation. Convergence of energy and charge has been verified, this is for the study of properties basic state of the compound. It was found that the calculated initial cell constants at equilibrium are very close to previous theoretical and experimental works. The electronic properties of the energy band structure and the total density of states confirmed that the CdSe compound has a direct energy gap estimated at 1.52 eV, which is very close to the previous applied results. The general results of the calculated optical properties including the imaginary part of the dielectric constant, absorption coefficient, reflectivity, optical conductance, refractive index, and extinction coefficient of cubic phase CdSe under the imposed conditions are discussed and compared with previous works. Through our results, new and important optical properties of the compound were highlighted, and then determine the areas of its use in the appropriate technological industries.","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136377810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.15251/cl.2023.208.599
K. A. Mohammed, N. A. Al Hasan, L. R. N. H. J., D. S. Abdul-Zahra, Y. D. Dwivedi, K. H. Salem, M. K. Agarwal, R. Zabibah, M. A. Alkhafaji
This study examined the properties of polyvinyl alcohol (PVA) as a matrix composite, specifically focusing on the characterization techniques of UV-Visible spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDX). The investigation centered around a novel hybrid structure composed of CdZnS nanoparticles implanted within a composite matrix of PVA and Fe2O3. The analysis of microstructure data provided evidence of the influence of CdZnS nanoparticles on the structural characteristics of PVA–Fe2O3. The composites that were synthesized exhibited significant absorption peaks at wavelengths of 233 nm and 234 nm for PVA-Fe2O3 and PVA-Fe2O3-CdZnS, respectively. A progressive shift towards higher wavelength regions of absorption was found in these composites. The X-ray diffraction (XRD) analysis revealed an average crystalline grain size of 38.417 nm for Fe2O3 and 27.267 nm for PVA-Fe2O3-CdZnS.
{"title":"Characterization of new hybrid composites of PVA-Fe2O3-CdZnS","authors":"K. A. Mohammed, N. A. Al Hasan, L. R. N. H. J., D. S. Abdul-Zahra, Y. D. Dwivedi, K. H. Salem, M. K. Agarwal, R. Zabibah, M. A. Alkhafaji","doi":"10.15251/cl.2023.208.599","DOIUrl":"https://doi.org/10.15251/cl.2023.208.599","url":null,"abstract":"This study examined the properties of polyvinyl alcohol (PVA) as a matrix composite, specifically focusing on the characterization techniques of UV-Visible spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDX). The investigation centered around a novel hybrid structure composed of CdZnS nanoparticles implanted within a composite matrix of PVA and Fe2O3. The analysis of microstructure data provided evidence of the influence of CdZnS nanoparticles on the structural characteristics of PVA–Fe2O3. The composites that were synthesized exhibited significant absorption peaks at wavelengths of 233 nm and 234 nm for PVA-Fe2O3 and PVA-Fe2O3-CdZnS, respectively. A progressive shift towards higher wavelength regions of absorption was found in these composites. The X-ray diffraction (XRD) analysis revealed an average crystalline grain size of 38.417 nm for Fe2O3 and 27.267 nm for PVA-Fe2O3-CdZnS.","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48722587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.15251/cl.2023.208.549
D. Dekhil, H. Guessas, A. Nouri, S. Ullah
SnS thin films were synthesized using the spray pyrolysis method and then annealed at 350, 400, and 450°C. According to the crystallographic analysis, the obtained SnS thin films crystallized in the polycrystalline orthorhombic system. The grains measured 47, 66, and 37 nm for the samples annealed at 350, 400, and 450°C, respectively. SEM and AFM images indicate that the samples’ surfaces were completely covered. Thus, the grains of SnS nanostructures have a granular-like shape and vary in size depending on the annealing temperatures. The transmittance measurement shows that annealing the sample at 400 °C extends and improves its absorption range to 600 nm. The resulting band gap energies were 1.60 eV, 1.30 eV, and 2.55 eV for annealing at 350 °C, 400 °C, and 450 °C, respectively. Hall Effect measurements reveal that annealing SnS films at 400 °C enhances their electrical properties. The values of carrier mobility, conductivity, and carrier concentration are 1.678 ×105 Cm2/Vs, 9.756 ×10-5 Ω-1 cm-1 , and 3.168 ×1010Cm-3 , respectively. Additionally, the photocurrent response validates that all samples annealed at 350, 400, and 450 °C have p-type conductivity, with values of 13, 28, and 2.5 µA/Cm2, respectively. The best conductivity, carrier mobility, and photocurrent values are obtained by annealing at 400 °C. Therefore, SnS thin films can be an interesting choice for absorber layer applications in photovoltaic systems.
{"title":"Annealing effect on the photocurrent response of SnS thin films prepared by the chemical spray pyrolysis method","authors":"D. Dekhil, H. Guessas, A. Nouri, S. Ullah","doi":"10.15251/cl.2023.208.549","DOIUrl":"https://doi.org/10.15251/cl.2023.208.549","url":null,"abstract":"SnS thin films were synthesized using the spray pyrolysis method and then annealed at 350, 400, and 450°C. According to the crystallographic analysis, the obtained SnS thin films crystallized in the polycrystalline orthorhombic system. The grains measured 47, 66, and 37 nm for the samples annealed at 350, 400, and 450°C, respectively. SEM and AFM images indicate that the samples’ surfaces were completely covered. Thus, the grains of SnS nanostructures have a granular-like shape and vary in size depending on the annealing temperatures. The transmittance measurement shows that annealing the sample at 400 °C extends and improves its absorption range to 600 nm. The resulting band gap energies were 1.60 eV, 1.30 eV, and 2.55 eV for annealing at 350 °C, 400 °C, and 450 °C, respectively. Hall Effect measurements reveal that annealing SnS films at 400 °C enhances their electrical properties. The values of carrier mobility, conductivity, and carrier concentration are 1.678 ×105 Cm2/Vs, 9.756 ×10-5 Ω-1 cm-1 , and 3.168 ×1010Cm-3 , respectively. Additionally, the photocurrent response validates that all samples annealed at 350, 400, and 450 °C have p-type conductivity, with values of 13, 28, and 2.5 µA/Cm2, respectively. The best conductivity, carrier mobility, and photocurrent values are obtained by annealing at 400 °C. Therefore, SnS thin films can be an interesting choice for absorber layer applications in photovoltaic systems.","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47023421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.15251/cl.2023.208.579
Y. Zhang, J. Guo, Y. Zhang, Q. Y. Y. W., S. R. Zhang, Q. Lai
We investigated the structural, electronic, chemical bonding, and optical properties of β-AgBiS2 crystal by using the Perdew-Burke-Ernzerhof (PBE) functional and the hybrid functional Heyd Scuseria Ernzerhof (HSE) within the DFT formalism. The electronic band structures obtained by both methods indicate that β-AgBiS2 is an indirect band gap semiconductor with band gap of 0.571 and 1.025 eV, respectively. The electron density difference and Mulliken overlap population show that the Ag-S bonds and Bi-S bonds are both ionic bonds. The calculated optical absorption spectrum prove that β-AgBiS2 is a promising material for solar photovoltaic conversion
{"title":"First-principles calculation of electronic structure, chemical bonding and optical properties of β-AgBiS2","authors":"Y. Zhang, J. Guo, Y. Zhang, Q. Y. Y. W., S. R. Zhang, Q. Lai","doi":"10.15251/cl.2023.208.579","DOIUrl":"https://doi.org/10.15251/cl.2023.208.579","url":null,"abstract":"We investigated the structural, electronic, chemical bonding, and optical properties of β-AgBiS2 crystal by using the Perdew-Burke-Ernzerhof (PBE) functional and the hybrid functional Heyd Scuseria Ernzerhof (HSE) within the DFT formalism. The electronic band structures obtained by both methods indicate that β-AgBiS2 is an indirect band gap semiconductor with band gap of 0.571 and 1.025 eV, respectively. The electron density difference and Mulliken overlap population show that the Ag-S bonds and Bi-S bonds are both ionic bonds. The calculated optical absorption spectrum prove that β-AgBiS2 is a promising material for solar photovoltaic conversion","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45278552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.15251/cl.2023.208.573
R. Singh, S. Kimothi, M. Singh, U. Rani, A. Verma
In this research paper, we have prepared thin film of MoS2 by thermal evaporation technique and characterized it. This thin film depositions lead to amorphous thin film. To make it crystalline, thermal annealing of the film have deposited on the substrates at 800 o C for two hour under vacuum environment. X-ray diffraction data of thin film shows the poly-crystalline nature. The Atomic Force Microscopy (AFM) image of the thin film shows the crystallinity with regularly arranged grains. Furthermore, an unconventional MoS2 based FET device has been fabricated by depositing thin film of MoS2 on p-type silicon. Thereafter, its transfer and output characteristics have been studied. The results show n-type semiconductor behaviour with an on/off ratio of about 103 and field-effect mobility of ~0.015 cm2/V. s at VDS of 1 V.
{"title":"Structural and device fabrication of 2D-MoS2 thin film","authors":"R. Singh, S. Kimothi, M. Singh, U. Rani, A. Verma","doi":"10.15251/cl.2023.208.573","DOIUrl":"https://doi.org/10.15251/cl.2023.208.573","url":null,"abstract":"In this research paper, we have prepared thin film of MoS2 by thermal evaporation technique and characterized it. This thin film depositions lead to amorphous thin film. To make it crystalline, thermal annealing of the film have deposited on the substrates at 800 o C for two hour under vacuum environment. X-ray diffraction data of thin film shows the poly-crystalline nature. The Atomic Force Microscopy (AFM) image of the thin film shows the crystallinity with regularly arranged grains. Furthermore, an unconventional MoS2 based FET device has been fabricated by depositing thin film of MoS2 on p-type silicon. Thereafter, its transfer and output characteristics have been studied. The results show n-type semiconductor behaviour with an on/off ratio of about 103 and field-effect mobility of ~0.015 cm2/V. s at VDS of 1 V.","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41501629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.15251/cl.2023.208.563
K. Sun, Z. Liu, R. X. Wang, X. Ling, J. W. Sun
Ba0.7Sr0.3TiO3:Sm3+ modified KxNa(1-x)NbO3 ceramics with perovskite-type structure were synthesized via solid state sintering method. Sm3+ ions doping was designed for substituting both A and B sites in the ABO3 structure, Sm3+ doped Ba0.7Sr0.3TiO3 (Ba0.7Sr0.3TiO3:Sm3+) oxide precursor powders with the chemical formula of Ba0.7Sr0.3-xSmx(Ti1-xSmx)O3 (x=0.005 ， 0.015 ， 0.025) were synthesized. Combined Ba0.7Sr0.3TiO3:Sm3+ with K0.5Na0.5NbO3, the perovskite-type solid solution composite ceramics were fabricated via solid phase sintering method. X-Ray diffraction was used for investigating the phase structure of the precursor powders and luminescent composite ceramics. The photoluminescence properties of the Sm3+ ions in the Ba0.7Sr0.3TiO3-K0.5Na0.5NbO3 composite ceramic materials were systematically investigated by exploring the effects of composition of the composites, excitation wavelength and temperature on photoluminescence.
{"title":"Photoluminescence properties of Ba0.7Sr0.3TiO3:Sm3+ modified K0.5Na0.5NbO3 perovskite oxide ceramics","authors":"K. Sun, Z. Liu, R. X. Wang, X. Ling, J. W. Sun","doi":"10.15251/cl.2023.208.563","DOIUrl":"https://doi.org/10.15251/cl.2023.208.563","url":null,"abstract":"Ba0.7Sr0.3TiO3:Sm3+ modified KxNa(1-x)NbO3 ceramics with perovskite-type structure were synthesized via solid state sintering method. Sm3+ ions doping was designed for substituting both A and B sites in the ABO3 structure, Sm3+ doped Ba0.7Sr0.3TiO3 (Ba0.7Sr0.3TiO3:Sm3+) oxide precursor powders with the chemical formula of Ba0.7Sr0.3-xSmx(Ti1-xSmx)O3 (x=0.005 ， 0.015 ， 0.025) were synthesized. Combined Ba0.7Sr0.3TiO3:Sm3+ with K0.5Na0.5NbO3, the perovskite-type solid solution composite ceramics were fabricated via solid phase sintering method. X-Ray diffraction was used for investigating the phase structure of the precursor powders and luminescent composite ceramics. The photoluminescence properties of the Sm3+ ions in the Ba0.7Sr0.3TiO3-K0.5Na0.5NbO3 composite ceramic materials were systematically investigated by exploring the effects of composition of the composites, excitation wavelength and temperature on photoluminescence.","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43288161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.15251/cl.2023.208.559
M. Fida, S. Aldaghfag, M. Yaseen, M. Ishfaq
The structural, magnetic, optoelectronic, and thermoelectric (TE) characteristics of Nd2MgX4 (X = S, Se) are determined by utilizing the density functional theory (DFT) based full potential linearized augmented plane wave (FP-LAPW) method as employed in WEIN2k code. The exchange and correlation energies along with Coulomb interactions are brought into consideration by employing local density of approximation with Hubbard model (LDA+U). Tolerance (τ) factor and formation enthalpy were utilized to confirm the stability of both spinels. τ values are 0.70 and 0.68, and formation enthalpy values are (ΔHf) are -3.34 eV and -2.19 eV for Nd2MgX4 (X = S, Se), respectively. For Nd2MgX4 (X = S, Se) metallic behavior is found in spin up case while considerable bandgaps are found in spin down with half metallic bandgap (Eg) values of 1.82 and 1.26 eV (in spin down), correspondingly. The calculated magnetic moment for Nd2MgX4 (X = S, Se) are 12.0008 μB and 12.0003 μB, respectively. Furthermore, optical features including refractive index n(ω), dielectric constant 𝜀𝜀(𝜔𝜔), reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω) and extinction coefficient k(ω) are computed. The maximum calculated real part of dielectric constant 𝜀𝜀1(𝜔𝜔) values for Nd2MgX4 (X = S, Se) are 9.2 and 10.8, respectively. For Nd2MgX4 (X = S, Se), σ(ω) has maximum value of 7642.9 at 6.6 and 7592.5 (Ω cm)-1 at 5.99 eV, respectively. The various temperature dependent thermoelectric (TE) parameters along with figure of merit (ZT) are determined to get full insight into the TE behavior for both compounds by using BoltzTraP code. The computed ZT value for Nd2MgSe4 is 0.81 at 800 K while Nd2MgS4 has ZT value of 0.80 at 800 K. Results showed that both spinels have potential in spintronics and in cooling industries.
{"title":"Systematic investigation of magneto-electronic, structural, thermoelectric and optical properties of Nd2MgX4 (X = S, Se) compounds","authors":"M. Fida, S. Aldaghfag, M. Yaseen, M. Ishfaq","doi":"10.15251/cl.2023.208.559","DOIUrl":"https://doi.org/10.15251/cl.2023.208.559","url":null,"abstract":"The structural, magnetic, optoelectronic, and thermoelectric (TE) characteristics of Nd2MgX4 (X = S, Se) are determined by utilizing the density functional theory (DFT) based full potential linearized augmented plane wave (FP-LAPW) method as employed in WEIN2k code. The exchange and correlation energies along with Coulomb interactions are brought into consideration by employing local density of approximation with Hubbard model (LDA+U). Tolerance (τ) factor and formation enthalpy were utilized to confirm the stability of both spinels. τ values are 0.70 and 0.68, and formation enthalpy values are (ΔHf) are -3.34 eV and -2.19 eV for Nd2MgX4 (X = S, Se), respectively. For Nd2MgX4 (X = S, Se) metallic behavior is found in spin up case while considerable bandgaps are found in spin down with half metallic bandgap (Eg) values of 1.82 and 1.26 eV (in spin down), correspondingly. The calculated magnetic moment for Nd2MgX4 (X = S, Se) are 12.0008 μB and 12.0003 μB, respectively. Furthermore, optical features including refractive index n(ω), dielectric constant 𝜀𝜀(𝜔𝜔), reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω) and extinction coefficient k(ω) are computed. The maximum calculated real part of dielectric constant 𝜀𝜀1(𝜔𝜔) values for Nd2MgX4 (X = S, Se) are 9.2 and 10.8, respectively. For Nd2MgX4 (X = S, Se), σ(ω) has maximum value of 7642.9 at 6.6 and 7592.5 (Ω cm)-1 at 5.99 eV, respectively. The various temperature dependent thermoelectric (TE) parameters along with figure of merit (ZT) are determined to get full insight into the TE behavior for both compounds by using BoltzTraP code. The computed ZT value for Nd2MgSe4 is 0.81 at 800 K while Nd2MgS4 has ZT value of 0.80 at 800 K. Results showed that both spinels have potential in spintronics and in cooling industries.","PeriodicalId":9710,"journal":{"name":"Chalcogenide Letters","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43253330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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