TY  - JOUR
AU  - Ribić, Vesna
AU  - Recnik, Aleksander
AU  - Drazic, Goran
AU  - Podlogar, Matejka
AU  - Branković, Zorica
AU  - Branković, Goran
PY  - 2021
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1471
AB  - In our recent study (Ribie et al. 2020) we reported the structure of inversion boundaries (IBs) in Sb2O3 -doped ZnO. Here, we focus on IBs that form in SnO2-doped ZnO. Using atomic resolution scanning transmission electron microscopy (STEM) methods we confirm that in SnO2-doped ZnO the IBs form in head-to-head configuration, where ZnO4 tetrahedra in both ZnO domains point towards the IB plane composed of a close packed layer of octahedrally coordinated Sn and Zn atoms. The in-plane composition is driven by the local charge balance, following Pauling's principle of electroneutrality for ionic crystals, according to which the average oxidation state of cations is 3+. To satisfy this condition, the cation ratio in the IB-layer is Sn4+ : Zn2+ =1:1. This was confirmed by concentric electron probe analysis employing energy dispersive spectroscopy (EDS) showing that Sn atoms occupy 0.504 +/- 0.039 of the IB layer, while the rest of the octahedral sites are occupied by Zn. IBs in SnO2-doped ZnO occur in the lowest energy, IB3 translation state with the cation sublattice expansion of Delta IB(zn-zn) of +91 pm with corresponding O-sublattice contraction Delta IB(O-O) of -46 pm. Based on quantitative HRTEM and HAADF-STEM analysis of in-plane ordering of Sn and Zn atoms, we identified two types of short-range distributions, (i) zigzag and (ii) stripe. Our density functional theory (DFT) calculations showed that the energy difference between the two arrangements is small (similar to 6 meV) giving rise to their alternation within the octahedral IB layer. As a result, cation ordering intermittently changes its type and the direction to maximize intrinsic entropy of the IB layer driven by the in-plane electroneutrality and 6-fold symmetry restrictions. A long-range in-plane disorder, as shown by our work would enhance quantum well effect to phonon scattering, while Zn2+ located in the IB octahedral sites, would modify the the bandgap, and enhance the in-plane conductivity and concentration of carriers.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - TEM and DFT Study of Basal-plane Inversion Boundaries in SnO2-doped ZnO
EP  - 252
IS  - 2
SP  - 237
VL  - 53
DO  - 10.2298/SOS2102237R
ER  - 

@article{
author = "Ribić, Vesna and Recnik, Aleksander and Drazic, Goran and Podlogar, Matejka and Branković, Zorica and Branković, Goran",
year = "2021",
abstract = "In our recent study (Ribie et al. 2020) we reported the structure of inversion boundaries (IBs) in Sb2O3 -doped ZnO. Here, we focus on IBs that form in SnO2-doped ZnO. Using atomic resolution scanning transmission electron microscopy (STEM) methods we confirm that in SnO2-doped ZnO the IBs form in head-to-head configuration, where ZnO4 tetrahedra in both ZnO domains point towards the IB plane composed of a close packed layer of octahedrally coordinated Sn and Zn atoms. The in-plane composition is driven by the local charge balance, following Pauling's principle of electroneutrality for ionic crystals, according to which the average oxidation state of cations is 3+. To satisfy this condition, the cation ratio in the IB-layer is Sn4+ : Zn2+ =1:1. This was confirmed by concentric electron probe analysis employing energy dispersive spectroscopy (EDS) showing that Sn atoms occupy 0.504 +/- 0.039 of the IB layer, while the rest of the octahedral sites are occupied by Zn. IBs in SnO2-doped ZnO occur in the lowest energy, IB3 translation state with the cation sublattice expansion of Delta IB(zn-zn) of +91 pm with corresponding O-sublattice contraction Delta IB(O-O) of -46 pm. Based on quantitative HRTEM and HAADF-STEM analysis of in-plane ordering of Sn and Zn atoms, we identified two types of short-range distributions, (i) zigzag and (ii) stripe. Our density functional theory (DFT) calculations showed that the energy difference between the two arrangements is small (similar to 6 meV) giving rise to their alternation within the octahedral IB layer. As a result, cation ordering intermittently changes its type and the direction to maximize intrinsic entropy of the IB layer driven by the in-plane electroneutrality and 6-fold symmetry restrictions. A long-range in-plane disorder, as shown by our work would enhance quantum well effect to phonon scattering, while Zn2+ located in the IB octahedral sites, would modify the the bandgap, and enhance the in-plane conductivity and concentration of carriers.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "TEM and DFT Study of Basal-plane Inversion Boundaries in SnO2-doped ZnO",
pages = "252-237",
number = "2",
volume = "53",
doi = "10.2298/SOS2102237R"
}

Ribić, V., Recnik, A., Drazic, G., Podlogar, M., Branković, Z.,& Branković, G.. (2021). TEM and DFT Study of Basal-plane Inversion Boundaries in SnO2-doped ZnO. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 53(2), 237-252.
https://doi.org/10.2298/SOS2102237R

Ribić V, Recnik A, Drazic G, Podlogar M, Branković Z, Branković G. TEM and DFT Study of Basal-plane Inversion Boundaries in SnO2-doped ZnO. in Science of Sintering. 2021;53(2):237-252.
doi:10.2298/SOS2102237R .

Ribić, Vesna, Recnik, Aleksander, Drazic, Goran, Podlogar, Matejka, Branković, Zorica, Branković, Goran, "TEM and DFT Study of Basal-plane Inversion Boundaries in SnO2-doped ZnO" in Science of Sintering, 53, no. 2 (2021):237-252,
https://doi.org/10.2298/SOS2102237R . .

TY  - JOUR
AU  - Mitrović, Jelena
AU  - Počuča-Nešić, Milica
AU  - Luković Golić, Danijela
AU  - Ribić, Vesna
AU  - Branković, Zorica
AU  - Savić, Slavica M.
AU  - Dapčević, Aleksandra
AU  - Bernik, Slavko
AU  - Podlogar, Matejka
AU  - Kocen, Matej
AU  - Rapljenović, Zeljko
AU  - Ivek, Tomislav
AU  - Lazović, Vladimir
AU  - Dojčinović, Biljana
AU  - Branković, Goran
PY  - 2020
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1363
AB  - Antimony doped barium-stannate dense ceramic materials were synthesized using spark plasma sintering technique out of mechanically activated precursor powders. The influence of various Sb concentrations (x = 0.00 - 0.10) on properties of BaSn1-xSbxO3 ceramics was investigated. Relative densities of prepared samples were in the range of (79-96) %. TEM analysis revealed the presence of many dislocations in undoped BaSnO3, and their significant reduction upon doping with Sb. All samples except BaSn0.92Sb0.08O3 exhibit non-linear I-U characteristic, typical for semiconductors with potential barrier at grain boundaries. Low angle grain boundaries found only in BaSn0.92Sb0.08O3 caused the loss of potential barrier at grain boundaries which was confirmed by AC impedance spectroscopy measurements. Consequently, BaSn0.92Sb0.08O3 showed the lowest electrical resistivity and linear I-U characteristic. UV-vis analysis confirmed the increasing of band gap (Burstein-Moss shift) values in all doped samples.
PB  - Elsevier Sci Ltd, Oxford
T2  - Journal of the European Ceramic Society
T1  - The structural, electrical and optical properties of spark plasma sintered BaSn1-xSbxO3 ceramics
EP  - 5575
IS  - 15
SP  - 5566
VL  - 40
DO  - 10.1016/j.jeurceramsoc.2020.06.062
ER  - 

@article{
author = "Mitrović, Jelena and Počuča-Nešić, Milica and Luković Golić, Danijela and Ribić, Vesna and Branković, Zorica and Savić, Slavica M. and Dapčević, Aleksandra and Bernik, Slavko and Podlogar, Matejka and Kocen, Matej and Rapljenović, Zeljko and Ivek, Tomislav and Lazović, Vladimir and Dojčinović, Biljana and Branković, Goran",
year = "2020",
abstract = "Antimony doped barium-stannate dense ceramic materials were synthesized using spark plasma sintering technique out of mechanically activated precursor powders. The influence of various Sb concentrations (x = 0.00 - 0.10) on properties of BaSn1-xSbxO3 ceramics was investigated. Relative densities of prepared samples were in the range of (79-96) %. TEM analysis revealed the presence of many dislocations in undoped BaSnO3, and their significant reduction upon doping with Sb. All samples except BaSn0.92Sb0.08O3 exhibit non-linear I-U characteristic, typical for semiconductors with potential barrier at grain boundaries. Low angle grain boundaries found only in BaSn0.92Sb0.08O3 caused the loss of potential barrier at grain boundaries which was confirmed by AC impedance spectroscopy measurements. Consequently, BaSn0.92Sb0.08O3 showed the lowest electrical resistivity and linear I-U characteristic. UV-vis analysis confirmed the increasing of band gap (Burstein-Moss shift) values in all doped samples.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Journal of the European Ceramic Society",
title = "The structural, electrical and optical properties of spark plasma sintered BaSn1-xSbxO3 ceramics",
pages = "5575-5566",
number = "15",
volume = "40",
doi = "10.1016/j.jeurceramsoc.2020.06.062"
}

Mitrović, J., Počuča-Nešić, M., Luković Golić, D., Ribić, V., Branković, Z., Savić, S. M., Dapčević, A., Bernik, S., Podlogar, M., Kocen, M., Rapljenović, Z., Ivek, T., Lazović, V., Dojčinović, B.,& Branković, G.. (2020). The structural, electrical and optical properties of spark plasma sintered BaSn1-xSbxO3 ceramics. in Journal of the European Ceramic Society
Elsevier Sci Ltd, Oxford., 40(15), 5566-5575.
https://doi.org/10.1016/j.jeurceramsoc.2020.06.062

Mitrović J, Počuča-Nešić M, Luković Golić D, Ribić V, Branković Z, Savić SM, Dapčević A, Bernik S, Podlogar M, Kocen M, Rapljenović Z, Ivek T, Lazović V, Dojčinović B, Branković G. The structural, electrical and optical properties of spark plasma sintered BaSn1-xSbxO3 ceramics. in Journal of the European Ceramic Society. 2020;40(15):5566-5575.
doi:10.1016/j.jeurceramsoc.2020.06.062 .

Mitrović, Jelena, Počuča-Nešić, Milica, Luković Golić, Danijela, Ribić, Vesna, Branković, Zorica, Savić, Slavica M., Dapčević, Aleksandra, Bernik, Slavko, Podlogar, Matejka, Kocen, Matej, Rapljenović, Zeljko, Ivek, Tomislav, Lazović, Vladimir, Dojčinović, Biljana, Branković, Goran, "The structural, electrical and optical properties of spark plasma sintered BaSn1-xSbxO3 ceramics" in Journal of the European Ceramic Society, 40, no. 15 (2020):5566-5575,
https://doi.org/10.1016/j.jeurceramsoc.2020.06.062 . .

TY  - JOUR
AU  - Tasić, Nikola
AU  - Marinković Stanojević, Zorica
AU  - Branković, Zorica
AU  - Lačnjevac, Uroš
AU  - Ribić, Vesna
AU  - Žunić, Milan
AU  - Novaković, Tatjana
AU  - Podlogar, Matejka
AU  - Branković, Goran
PY  - 2016
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1003
AB  - In this paper, we propose a novel method for preparation of high surface area titania nanoparticles, and investigate their photovoltaic performance in dye sensitized solar cells (DSSCs). The precursor compound titanium(IV)-isopropoxide is hydrolyzed in the presence of nonionic surfactant (Triton X100) and ethylenediaminetetraacetic acid sodium salt (EDTA-Na-2) and thermally transformed into gel. The gel is autoclaved, resulting in submicronic micelles which are further processed into mesoporous films. The films are deposited from paste, composed of ultrasonically broken micelles and the organic ingredients. The crack-free film structures, composed of sub-25 nm pure anatase particles are observed using the appropriate instrumental techniques: scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), UV-VIS-NIR spectroscopy. The large surface area of 158 m(2) g (1) and mesoporosity are confirmed using the data obtained from the nitrogen adsorption-desorption isotherm. The photovoltaic performance of the operating N719-sensitized solar devices are tested using electrochemical impedance spectroscopy (EIS), open-circuit voltage decay (OCVD) and by recording current density-voltage (J-V) curves. The cell exhibits promising photocurrent density up to 11.7 mA cm (2), and the photo-to-electric power efficiency of 5.22%, for cell area of 0.24 cm(2), under 100 mW cm (2) halogen light source.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Electrochimica Acta
T1  - Mesoporous films prepared from synthesized TiO2 nanoparticles and their application in dye-sensitized solar cells (DSSCs)
EP  - 614
SP  - 606
VL  - 210
DO  - 10.1016/j.electacta.2016.05.179
ER  - 

@article{
author = "Tasić, Nikola and Marinković Stanojević, Zorica and Branković, Zorica and Lačnjevac, Uroš and Ribić, Vesna and Žunić, Milan and Novaković, Tatjana and Podlogar, Matejka and Branković, Goran",
year = "2016",
abstract = "In this paper, we propose a novel method for preparation of high surface area titania nanoparticles, and investigate their photovoltaic performance in dye sensitized solar cells (DSSCs). The precursor compound titanium(IV)-isopropoxide is hydrolyzed in the presence of nonionic surfactant (Triton X100) and ethylenediaminetetraacetic acid sodium salt (EDTA-Na-2) and thermally transformed into gel. The gel is autoclaved, resulting in submicronic micelles which are further processed into mesoporous films. The films are deposited from paste, composed of ultrasonically broken micelles and the organic ingredients. The crack-free film structures, composed of sub-25 nm pure anatase particles are observed using the appropriate instrumental techniques: scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), UV-VIS-NIR spectroscopy. The large surface area of 158 m(2) g (1) and mesoporosity are confirmed using the data obtained from the nitrogen adsorption-desorption isotherm. The photovoltaic performance of the operating N719-sensitized solar devices are tested using electrochemical impedance spectroscopy (EIS), open-circuit voltage decay (OCVD) and by recording current density-voltage (J-V) curves. The cell exhibits promising photocurrent density up to 11.7 mA cm (2), and the photo-to-electric power efficiency of 5.22%, for cell area of 0.24 cm(2), under 100 mW cm (2) halogen light source.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Electrochimica Acta",
title = "Mesoporous films prepared from synthesized TiO2 nanoparticles and their application in dye-sensitized solar cells (DSSCs)",
pages = "614-606",
volume = "210",
doi = "10.1016/j.electacta.2016.05.179"
}

Tasić, N., Marinković Stanojević, Z., Branković, Z., Lačnjevac, U., Ribić, V., Žunić, M., Novaković, T., Podlogar, M.,& Branković, G.. (2016). Mesoporous films prepared from synthesized TiO2 nanoparticles and their application in dye-sensitized solar cells (DSSCs). in Electrochimica Acta
Pergamon-Elsevier Science Ltd, Oxford., 210, 606-614.
https://doi.org/10.1016/j.electacta.2016.05.179

Tasić N, Marinković Stanojević Z, Branković Z, Lačnjevac U, Ribić V, Žunić M, Novaković T, Podlogar M, Branković G. Mesoporous films prepared from synthesized TiO2 nanoparticles and their application in dye-sensitized solar cells (DSSCs). in Electrochimica Acta. 2016;210:606-614.
doi:10.1016/j.electacta.2016.05.179 .

Tasić, Nikola, Marinković Stanojević, Zorica, Branković, Zorica, Lačnjevac, Uroš, Ribić, Vesna, Žunić, Milan, Novaković, Tatjana, Podlogar, Matejka, Branković, Goran, "Mesoporous films prepared from synthesized TiO2 nanoparticles and their application in dye-sensitized solar cells (DSSCs)" in Electrochimica Acta, 210 (2016):606-614,
https://doi.org/10.1016/j.electacta.2016.05.179 . .

TY  - JOUR
AU  - Bernik, Slavko
AU  - Branković, Goran
AU  - Rustja, S.
AU  - Žunić, Milan
AU  - Podlogar, Matejka
AU  - Branković, Zorica
PY  - 2008
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/245
AB  - ZnO-based varistor samples were prepared by the direct mixing of the constituent phases (DMCP) and sintering at 1100 degrees C for 2 h. The influence of the starting powder mixture's composition - the amounts of the pre-reacted varistor compounds and their composition - and its preparation, either with or without mechano-chemical activation (MCA), on the microstructure, phase composition and electrical characteristics of the varistor samples was studied. It showed that MCA improved the density and microstructural homogeneity of the varistor samples. MCA strongly affected the grain growth: it enhanced the nucleation of inversion boundaries (IBs) in the ZnO grains and the IBs-induced grain-growth mechanism resulted in uniform grain growth and hence a microstructure with smaller ZnO grains and a narrower grain size distribution. The final phase composition of the samples prepared by the DMCP method mainly depended on the presence of varistor dopants that can prevent the formation of the pyrochlore phase, especially Cr2O3, while MCA can affect it mostly by providing a homogeneous distribution of those dopants. The DMCP varistor samples prepared with MCA had much better Current-voltage characteristics than the samples of the same composition prepared from unactivated powders.
PB  - Elsevier Sci Ltd, Oxford
T2  - Ceramics International
T1  - Microstructural and compositional aspects of ZnO-based varistor ceramics prepared by direct mixing of the constituent phases and high-energy milling
EP  - 1502
IS  - 6
SP  - 1495
VL  - 34
DO  - 10.1016/j.ceramint.2007.04.003
ER  - 

@article{
author = "Bernik, Slavko and Branković, Goran and Rustja, S. and Žunić, Milan and Podlogar, Matejka and Branković, Zorica",
year = "2008",
abstract = "ZnO-based varistor samples were prepared by the direct mixing of the constituent phases (DMCP) and sintering at 1100 degrees C for 2 h. The influence of the starting powder mixture's composition - the amounts of the pre-reacted varistor compounds and their composition - and its preparation, either with or without mechano-chemical activation (MCA), on the microstructure, phase composition and electrical characteristics of the varistor samples was studied. It showed that MCA improved the density and microstructural homogeneity of the varistor samples. MCA strongly affected the grain growth: it enhanced the nucleation of inversion boundaries (IBs) in the ZnO grains and the IBs-induced grain-growth mechanism resulted in uniform grain growth and hence a microstructure with smaller ZnO grains and a narrower grain size distribution. The final phase composition of the samples prepared by the DMCP method mainly depended on the presence of varistor dopants that can prevent the formation of the pyrochlore phase, especially Cr2O3, while MCA can affect it mostly by providing a homogeneous distribution of those dopants. The DMCP varistor samples prepared with MCA had much better Current-voltage characteristics than the samples of the same composition prepared from unactivated powders.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Ceramics International",
title = "Microstructural and compositional aspects of ZnO-based varistor ceramics prepared by direct mixing of the constituent phases and high-energy milling",
pages = "1502-1495",
number = "6",
volume = "34",
doi = "10.1016/j.ceramint.2007.04.003"
}

Bernik, S., Branković, G., Rustja, S., Žunić, M., Podlogar, M.,& Branković, Z.. (2008). Microstructural and compositional aspects of ZnO-based varistor ceramics prepared by direct mixing of the constituent phases and high-energy milling. in Ceramics International
Elsevier Sci Ltd, Oxford., 34(6), 1495-1502.
https://doi.org/10.1016/j.ceramint.2007.04.003

Bernik S, Branković G, Rustja S, Žunić M, Podlogar M, Branković Z. Microstructural and compositional aspects of ZnO-based varistor ceramics prepared by direct mixing of the constituent phases and high-energy milling. in Ceramics International. 2008;34(6):1495-1502.
doi:10.1016/j.ceramint.2007.04.003 .

Bernik, Slavko, Branković, Goran, Rustja, S., Žunić, Milan, Podlogar, Matejka, Branković, Zorica, "Microstructural and compositional aspects of ZnO-based varistor ceramics prepared by direct mixing of the constituent phases and high-energy milling" in Ceramics International, 34, no. 6 (2008):1495-1502,
https://doi.org/10.1016/j.ceramint.2007.04.003 . .