Roxana Elena Patru
Verified @infim.ro
Scopus Publications
- Downscaling grain size toward the nanometre range – A key-factor for tuning the crystalline structure, phase transitions, dielectric and ferroelectric behaviour in Ba0·8Sr0·2TiO3 ceramics
R.E. Pătru, C.A. Stanciu, V.A. Surdu, E.M. Soare, R.D. Truşcă, B.S. Vasile, A.I. Nicoară, L. Trupină, I. Pasuk, M. Botea, N. Horchidan, L. Mitoşeriu, L. Pintilie, I. Pintilie, A.C. Ianculescu
Progress in Solid State Chemistry, 2024 - High-Entropy Lead-Free Perovskite Bi0.2K0.2Ba0.2Sr0.2Ca0.2TiO3 Powders and Related Ceramics: Synthesis, Processing, and Electrical Properties
Vasile-Adrian Surdu, Mariana-Andreea Marinică, Roxana-Elena Pătru, Ovidiu-Cristian Oprea, Adrian Ionuț Nicoară, Bogdan Ștefan Vasile, Roxana Trușca, Adelina-Carmen Ianculescu
Nanomaterials, 2023
A novel high-entropy perovskite powder with the composition Bi0.2K0.2Ba0.2Sr0.2Ca0.2TiO3 was successfully synthesized using a modified Pechini method. The precursor powder underwent characterization through Fourier Transform Infrared Spectroscopy and thermal analysis. The resultant Bi0.2K0.2Ba0.2Sr0.2Ca0.2TiO3 powder, obtained post-calcination at 900 °C, was further examined using a variety of techniques including X-ray diffraction, Raman spectroscopy, X-ray fluorescence, scanning electron microscopy, and transmission electron microscopy. Ceramic samples were fabricated by conventional sintering at various temperatures (900, 950, and 1000 °C). The structure, microstructure, and dielectric properties of these ceramics were subsequently analyzed and discussed. The ceramics exhibited a two-phase composition comprising cubic and tetragonal perovskites. The grain size was observed to increase from 35 to 50 nm, contingent on the sintering temperature. All ceramic samples demonstrated relaxor behavior with a dielectric maximum that became more flattened and shifted towards lower temperatures as the grain size decreased. - Influence of Grain Size on Dielectric Behavior in Lead-Free 0.5 Ba(Zr0.2Ti0.8)O3–0.5 (Ba0.7Ca0.3)TiO3 Ceramics
Vladimir Lucian Ene, Valentin Razvan Lupu, Claudiu Vasile Condor, Roxana Elena Patru, Luminita Mirela Hrib, Luminita Amarande, Adrian Ionut Nicoara, Lucian Pintilie, Adelina-Carmen Ianculescu
Nanomaterials, 2023
Fine-tuning of grain sizes can significantly influence the interaction between different dielectric phenomena, allowing the development of materials with tailored dielectric resistivity. By virtue of various synthesis mechanisms, a pathway to manipulate grain sizes and, consequently, tune the material’s dielectric response is revealed. Understanding these intricate relationships between granulation and dielectric properties can pave the way for designing and optimizing materials for specific applications where tailored dielectric responses are sought. The experimental part involved the fabrication of dense BCT-BZT ceramics with different grain sizes by varying the synthesis (conventional solid-state reaction route and sol-gel) and consolidation methods. Both consolidation methods produced well-crystallized specimens, with Ba0.85Ca0.15O3Ti0.9Zr0.1 (BCTZ) perovskite as the major phase. Conventional sintering resulted in microstructured and submicron-structured BCT-BZT ceramics, with average grain sizes of 2.35 μm for the solid-state sample and 0.91 μm for the sol-gel synthesized ceramic. However, spark plasma sintering produced a nanocrystalline specimen with an average grain size of 67.5 nm. As the grain size decreases, there is a noticeable decrease in the maximum permittivity, a significant reduction in dielectric losses, and a shifting of the Curie temperature towards lower values. - Grain size-driven effect on the functional properties in Ba0.6Sr0.4TiO3 ceramics consolidated by spark plasma sintering
Roxana-Elena Pătru, Cătălina Andreea Stanciu, Elena Mirabela Soare, Vasile-Adrian Surdu, Roxana Doina Truşcă, Adrian Ionuţ Nicoară, Bogdan Ştefan Vasile, Georgia Boni, Luminiţa Amarande, Nadejda Horchidan, Lavinia Petronela Curecheriu, Liliana Mitoşeriu, Lucian Pintilie, Ioana Pintilie, Adelina-Carmen Ianculescu
Journal of the European Ceramic Society, 2023 - Capacitive and Inductive Effects in Perovskite Solar Cells: The Different Roles of Ionic Current and Ionic Charge Accumulation
Nicolae Filipoiu, Amanda Teodora Preda, Dragos-Victor Anghel, Roxana Patru, Rachel Elizabeth Brophy, Movaffaq Kateb, Cristina Besleaga, Andrei Gabriel Tomulescu, Ioana Pintilie, Andrei Manolescu, George Alexandru Nemnes
Physical Review Applied, 2022
, - Negative Capacitance and Switching Dynamics Control Via Non-Ferroelectric Elements
Andra Georgia Boni, Roxana Patru, Lucian D. Filip, Cristina Chirila, Iuliana Pasuk, Ioana Pintilie, Lucian Pintilie
ACS Applied Energy Materials, 2022
Complex ferroelectric structures with dielectric inter-layers may become possible alternatives for neuromorphic computing and low-power field-effect transistors since they exhibit multiple polarization states and negative capacitance. However, the effects on the switching characteristics due to the electric properties of the non-ferroelectric circuit element have not been clearly evaluated so far. A high-resistance or low-capacitance element is usually associated with an increased depolarization field and eventually with suppression of polarization but without further consideration of the electrostatic differences. Therefore, we show that switching behavior is dramatically changed if the non-FE element is a resistive component or a capacitive one. This is reflected by either an increased apparent coercive field or imprint, respectively. A negative capacitance regime was observed at different moments but strongly depends on the nature of the non-ferroelectric element. The voltage on the ferroelectric component remains constant during switching, which is a fingerprint of the system passing through non-equilibrium states. Therefore, we propose an algorithm to recover the S-shape of polarization dependence on the ferroelectric internal voltage during the slowed transition between the two stable states of polarization. - Tetragonal–cubic phase transition and low-field dielectric properties of ch3nh3pbi3 crystals
Roxana Patru, Hamidreza Khassaf, Iuliana Pasuk, Mihaela Botea, Lucian Trupina, Constantin-Paul Ganea, Lucian Pintilie, Ioana Pintilie
Materials, 2021
The frequency and temperature dependence of dielectric properties of CH3NH3PbI3 (MAPI) crystals have been studied and analyzed in connection with temperature-dependent structural studies. The obtained results bring arguments for the existence of ferroelectricity and aim to complete the current knowledge on the thermally activated conduction mechanisms, in dark equilibrium and in the presence of a small external a.c. electric field. The study correlates the frequency-dispersive dielectric spectra with the conduction mechanisms and their relaxation processes, as well as with the different transport regimes indicated by the Nyquist plots. The different energy barriers revealed by the impedance spectroscopy highlight the dominant transport mechanisms in different frequency and temperature ranges, being associated with the bulk of the grains, their boundaries, and/or the electrodes’ interfaces. - Enhancing stability of hybrid perovskite solar cells by imidazolium incorporation
Andrei Gabriel Tomulescu, Lucia Nicoleta Leonat, Florentina Neațu, Viorica Stancu, Vasilica Toma, Sarah Derbali, Ștefan Neațu, Arpad Mihai Rostas, Cristina Beșleagă, Roxana Pătru, Ioana Pintilie, Mihaela Florea
Solar Energy Materials and Solar Cells, 2021 - Structural, functional properties and enhanced thermal stability of bulk graded (Ba,Sr)TiO3structures obtained by spark plasma sintering
Mihaela Botea, Ioana Pintilie, Vasile-Adrian Surdu, Cătălina-Andreea Stanciu, Roxana-Doina Truşcă, Bogdan Ştefan Vasile, Roxana Patru, Adelina-Carmen Ianculescu, Lucian Pintilie
Journal of Materials Research and Technology, 2021
Graded structures with different architectures were obtained by spark plasma sintering from (Ba1-xSrx)TiO3 (BST, x = 0.10; 0.20; 0.30) powders. The presence of the composition gradient was confirmed by structural and compositional investigations using X-ray diffraction and electron microscopy combined with energy dispersive X-ray spectroscopy. The concentration gradient was either asymmetric (3 layers, starting with x = 0.10 and ending with x = 0.30) or symmetric (5 or 6 layers, starting and ending with x = 0.10, and with a single or double x = 0.30 layer in the middle, respectively). Electrical measurements reveal a decrease of the dielectric constant with increasing the number of the layers. It was found that the symmetric graded structure with 6 layers has the best thermal stability of both, the dielectric constant (variation of only 8% between zero and 100 °C) and the pyroelectric coefficient (6% variation between zero and 80 °C). In addition, an enhancement of the pyroelectric signal for frequencies above 100 Hz is obtained in symmetric structures, an effect that is attributed to the additive contributions of the signals originated from the layers with different Sr content. - (Ba,Sr)TiO3 solid solutions sintered from sol-gel derived powders: An insight into the composition and temperature dependent dielectric behavior
Roxana Elena Patru, Constantin Paul Ganea, Catalina-Andreea Stanciu, Vasile-Adrian Surdu, Roxana Trusca, Adelina-Carmen Ianculescu, Ioana Pintilie, Lucian Pintilie
Ceramics International, 2020 - PVDF–ferrite composites with dual magneto-piezoelectric response for flexible electronics applications: synthesis and functional properties
Felicia Gheorghiu, Roxana Stanculescu, Lavinia Curecheriu, Elisabetta Brunengo, Paola Stagnaro, Vasile Tiron, Petronel Postolache, Maria Teresa Buscaglia, Liliana Mitoseriu
Journal of Materials Science, 2020 - Structural and functional properties of BaTiO3 porous ceramics produced by using pollen as sacrificial template
Vlad Alexandru Lukacs, Roxana Stanculescu, Lavinia Curecheriu, Cristina Elena Ciomaga, Nadejda Horchidan, Cipriana Cioclea, Liliana Mitoseriu
Ceramics International, 2020 - Porous (Ba,Sr)TiO3 ceramics for tailoring dielectric and tunability properties: Modelling and experiment
Roxana Stanculescu, Nadejda Horchidan, Carmen Galassi, Mihai Asandulesa, Leontin Padurariu, Cristina Ciomaga, Liliana Mitoseriu
Processing and Application of Ceramics, 2017 - Effect of particle size and volume fraction of BaTiO3 powders on the functional properties of BaTiO3/poly(ε-caprolactone) composites
M. Airimioaei, R. Stanculescu, V. Preutu, C. Ciomaga, N. Horchidan, S. Tascu, D. Lutic, A. Pui, L. Mitoseriu
Materials Chemistry and Physics, 2016 - The influence of post-sintering re-oxidation treatment on dielectric response of dense and porous Ba0.70Sr0.30TiO3 ceramics
Roxana E. Stanculescu, Cristina E. Ciomaga, Nadejda Horchidan, Carmen Galassi, Florin Mihai Tufescu, Liliana Mitoseriu
Ceramics International, 2016 - Study of the role of porosity on the functional properties of (Ba,Sr)TiO3 ceramics
Roxana Stanculescu, Cristina E. Ciomaga, Leontin Padurariu, Pietro Galizia, Nadejda Horchidan, Claudio Capiani, Carmen Galassi, Liliana Mitoseriu
Journal of Alloys and Compounds, 2015 - Investigation of low field dielectric properties of anisotropic porous Pb(Zr,Ti)O3 ceramics: Experiment and modeling
C. S. Olariu, L. Padurariu, R. Stanculescu, C. Baldisserri, C. Galassi, L. Mitoseriu
Journal of Applied Physics, 2013 - Solvatochromism used in determining some molecular electro-optical parameters
Luminita Stroia, Roxana-Elena Stanculescu, Dana Ortansa Dorohoi
Proceedings of SPIE the International Society for Optical Engineering, 2011
RECENT SCHOLAR PUBLICATIONS
- Electrical Properties of Binary Thin Films
LM Hrib, LM Balescu, CF Chirila, AG Boni, DG Popescu, MC Istrate, ...
IntechOpen , 2026
2026 - Improved ionic conductivity in Spark Plasma Sintering-processed NASICON solid electrolytes: Correlation between structure, microstructure, and impedance analysis
NEH Bouftila, A Chouiekh, AC Galca, AM Rostas, RE Patru, LN Leonat, ...
Journal of Power Sources 666, 239110 , 2026
2026 - Gain-Layer Project
NG Sorgenfrei, AR Altamura, C Besleaga, GA Boni, T Ceponis, P Erberk, ...
arXiv preprint arXiv:2601.16049 , 2026
2026 - Composition-dependent structural, microstructural and functional characteristics of fine-grained BaTi1-xHfxO3 ceramics consolidated by Spark Plasma Sintering
EM Soare, CA Stanciu, RE Pătru, VA Surdu, N Horchidan, L Mitoşeriu, ...
Journal of the European Ceramic Society 45 (15), 117600 , 2025
2025 - Grain size effects in BaTi0. 90Hf0. 10O3 ceramics with phase coexistence: the influence of nanostructuring and of the internal stress on the functional properties
EM Soare, CA Stanciu, RE Pătru, VA Surdu, L Pădurariu, N Horchidan, ...
Journal of Materials Research and Technology , 2025
2025 - Experimental and theoretical perspective on band gap modulation in Sr2+ modified BaTiO3 capacitors
Y Zidi, O Khaldi, RE Patru, LN Leonat, M Enculescu, V Toma, ...
Ceramics International 51 (13), 18166-18177 , 2025
2025
Citations: 8 - Effect of transition metal ions on the dielectric properties of chromium potassium phosphates
Z Mighri, RE Patru, LN Leonat, O El Khouja, H Nasri, AM Rostas, ...
Journal of Alloys and Compounds 1009, 176870 , 2024
2024
Citations: 3 - Impact of interface defects on the band alignment and performance of TiO /MAPI/Cu O perovskite solar cells
N Filipoiu, M Cuzminschi, M Cosinschi, CA Pantis-Simut, K Torfason, ...
arXiv preprint arXiv:2406.19594 , 2024
2024
Citations: 1 - DC current-voltage and impedance spectroscopy characterization of nCdS/pZnTe HJ
I Lungu, RE Patru, AC Galca, L Pintilie, T Potlog
Scientific reports 14 (1), 12955 , 2024
2024
Citations: 7 - Downscaling grain size toward the nanometre range–A key-factor for tuning the crystalline structure, phase transitions, dielectric and ferroelectric behaviour in Ba0· 8Sr0 …
RE Pătru, CA Stanciu, VA Surdu, EM Soare, RD Truşcă, BS Vasile, ...
Progress in Solid State Chemistry 74, 100457 , 2024
2024
Citations: 8 - Detector R&D; Collaboration for Solid-State detectors
C Hahn, M Backhaus, E Fretwurst, U Husemann, S Ozturk, X Li, M Mikuz, ...
2023 - High-Entropy Lead-Free Perovskite Bi 0.2 K 0.2 Ba 0.2 Sr 0.2 Ca 0.2 TiO 3 Powders and Related Ceramics: Synthesis, Processing, and Electrical Properties
VA Surdu, MA Marinică, RE Pătru, OC Oprea, AI Nicoară, BȘ Vasile, ...
Nanomaterials 13 (22), 2974 , 2023
2023
Citations: 13 - Influence of Grain Size on Dielectric Behavior in Lead-Free 0.5 Ba(Zr 0.2 Ti 0.8 )O 3 –0.5 (Ba 0.7 Ca 0.3 )TiO 3 Ceramics
VL Ene, VR Lupu, CV Condor, RE Patru, LM Hrib, L Amarande, ...
Nanomaterials 13 (22), 2934 , 2023
2023
Citations: 22 - Grain size-driven effect on the functional properties in Ba0. 6Sr0. 4TiO3 ceramics consolidated by spark plasma sintering
RE Pătru, CA Stanciu, EM Soare, VA Surdu, RD Truşcă, AI Nicoară, ...
Journal of the European Ceramic Society 43 (8), 3250-3265 , 2023
2023
Citations: 14 - Structural and electrical properties of novel Cr/Fe mixed transition-metal phosphates
Z Mighri, K Souiwa, AM Rostas, RE Patru, AE Bocirnea, N Iacob, ...
Inorganic Chemistry 62 (22), 8530-8542 , 2023
2023
Citations: 9 - DC current-voltage and impedance spectroscopy characterization of CdS/ZnTe heterostructures
I Lungu, RE Patru, AC Galca, L Pintilie, T Potlog
Application-oriented material development, 11-11 , 2023
2023 - Capacitive and inductive effects in perovskite solar cells: the different roles of ionic current and ionic charge accumulation
N Filipoiu, AT Preda, DV Anghel, R Patru, RE Brophy, M Kateb, ...
Physical Review Applied 18 (6), 064087 , 2022
2022
Citations: 33 - Negative Capacitance and Switching Dynamics Control Via Non-Ferroelectric Elements
AG Boni, R Patru, LD Filip, C Chirila, I Pasuk, I Pintilie, L Pintilie
ACS Applied Energy Materials 5 (3), 3307-3318 , 2022
2022
Citations: 4 - Enhancing stability of hybrid perovskite solar cells by imidazolium incorporation
AG Tomulescu, LN Leonat, F Neațu, V Stancu, V Toma, S Derbali, ...
Solar Energy Materials and Solar Cells 227, 111096 , 2021
2021
Citations: 21 - Tetragonal–Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals
RE Patru, H Khassaf, I Pasuk, M Botea, L Trupina, CP Ganea, L Pintilie, ...
Materials 14 (15), 4215 , 2021
2021
Citations: 19
MOST CITED SCHOLAR PUBLICATIONS
- Study of the role of porosity on the functional properties of (Ba,Sr)TiO3 ceramics
R Stanculescu, CE Ciomaga, L Padurariu, P Galizia, N Horchidan, ...
Journal of Alloys and Compounds 643, 79-87 , 2015
2015
Citations: 67 - PVDF–ferrite composites with dual magneto-piezoelectric response for flexible electronics applications: synthesis and functional properties
F Gheorghiu, R Stanculescu, L Curecheriu, E Brunengo, P Stagnaro, ...
Journal of Materials Science 55 (9), 3926-3939 , 2020
2020
Citations: 58 - Structural and functional properties of BaTiO3 porous ceramics produced by using pollen as sacrificial template
VA Lukacs, R Stanculescu, L Curecheriu, CE Ciomaga, N Horchidan, ...
doi.org/10.1016/J.CERAMINT.2019.08.292 , 2020
2020
Citations: 36 - Capacitive and inductive effects in perovskite solar cells: the different roles of ionic current and ionic charge accumulation
N Filipoiu, AT Preda, DV Anghel, R Patru, RE Brophy, M Kateb, ...
Physical Review Applied 18 (6), 064087 , 2022
2022
Citations: 33 - Investigation of low field dielectric properties of anisotropic porous Pb(Zr,Ti)O3 ceramics: Experiment and modeling
CS Olariu, L Padurariu, R Stanculescu, C Baldisserri, C Galassi, ...
Journal of Applied Physics 114, 214101 , 2013
2013
Citations: 25 - Influence of Grain Size on Dielectric Behavior in Lead-Free 0.5 Ba(Zr 0.2 Ti 0.8 )O 3 –0.5 (Ba 0.7 Ca 0.3 )TiO 3 Ceramics
VL Ene, VR Lupu, CV Condor, RE Patru, LM Hrib, L Amarande, ...
Nanomaterials 13 (22), 2934 , 2023
2023
Citations: 22 - Enhancing stability of hybrid perovskite solar cells by imidazolium incorporation
AG Tomulescu, LN Leonat, F Neațu, V Stancu, V Toma, S Derbali, ...
Solar Energy Materials and Solar Cells 227, 111096 , 2021
2021
Citations: 21 - Effect of particle size and volume fraction of BaTiO3 powders on the functional properties of BaTiO3/poly(epsilon-caprolactone) composites
M Airimioaei, R Stanculescu, V Preutu, C Ciomaga, N Horchidan, S Tascu, ...
Materials Chemistry and Physics 182, 246-255 , 2016
2016
Citations: 20 - Tetragonal–Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals
RE Patru, H Khassaf, I Pasuk, M Botea, L Trupina, CP Ganea, L Pintilie, ...
Materials 14 (15), 4215 , 2021
2021
Citations: 19 - Porous (Ba, Sr) TiO3 ceramics for tailoring dielectric and tunability properties: Modelling and experiment
RE Stanculescu, N Horchidan, C Galassi, M Asandulesa, L Padurariu, ...
Processing and Application of Ceramics 11 (4), 235-246 , 2017
2017
Citations: 19 - The influence of post-sintering re-oxidation treatment on dielectric response of dense and porous Ba0.70Sr0.30TiO3 ceramics
RE Stanculescu, CE Ciomaga, N Horchidan, C Galassi, FM Tufescu, ...
Ceramics International 42 (1), 527-536 , 2016
2016
Citations: 18 - (Ba, Sr) TiO3 solid solutions sintered from sol-gel derived powders: An insight into the composition and temperature dependent dielectric behavior
RE Patru, CP Ganea, CA Stanciu, VA Surdu, R Trusca, AC Ianculescu, ...
Ceramics International 46 (4), 4180-4190 , 2020
2020
Citations: 15 - Grain size-driven effect on the functional properties in Ba0. 6Sr0. 4TiO3 ceramics consolidated by spark plasma sintering
RE Pătru, CA Stanciu, EM Soare, VA Surdu, RD Truşcă, AI Nicoară, ...
Journal of the European Ceramic Society 43 (8), 3250-3265 , 2023
2023
Citations: 14 - High-Entropy Lead-Free Perovskite Bi 0.2 K 0.2 Ba 0.2 Sr 0.2 Ca 0.2 TiO 3 Powders and Related Ceramics: Synthesis, Processing, and Electrical Properties
VA Surdu, MA Marinică, RE Pătru, OC Oprea, AI Nicoară, BȘ Vasile, ...
Nanomaterials 13 (22), 2974 , 2023
2023
Citations: 13 - Structural and electrical properties of novel Cr/Fe mixed transition-metal phosphates
Z Mighri, K Souiwa, AM Rostas, RE Patru, AE Bocirnea, N Iacob, ...
Inorganic Chemistry 62 (22), 8530-8542 , 2023
2023
Citations: 9 - Experimental and theoretical perspective on band gap modulation in Sr2+ modified BaTiO3 capacitors
Y Zidi, O Khaldi, RE Patru, LN Leonat, M Enculescu, V Toma, ...
Ceramics International 51 (13), 18166-18177 , 2025
2025
Citations: 8 - Downscaling grain size toward the nanometre range–A key-factor for tuning the crystalline structure, phase transitions, dielectric and ferroelectric behaviour in Ba0· 8Sr0 …
RE Pătru, CA Stanciu, VA Surdu, EM Soare, RD Truşcă, BS Vasile, ...
Progress in Solid State Chemistry 74, 100457 , 2024
2024
Citations: 8 - DC current-voltage and impedance spectroscopy characterization of nCdS/pZnTe HJ
I Lungu, RE Patru, AC Galca, L Pintilie, T Potlog
Scientific reports 14 (1), 12955 , 2024
2024
Citations: 7 - Structural, functional properties and enhanced thermal stability of bulk graded (Ba,Sr)TiO3 structures obtained by spark plasma sintering
M Botea, I Pintilie, VA Surdu, CA Stanciu, RD Trusca, BS Vasile, R Patru, ...
Journal of Materials Research and Technology 12, 2085-2103 , 2021
2021
Citations: 7 - Negative Capacitance and Switching Dynamics Control Via Non-Ferroelectric Elements
AG Boni, R Patru, LD Filip, C Chirila, I Pasuk, I Pintilie, L Pintilie
ACS Applied Energy Materials 5 (3), 3307-3318 , 2022
2022
Citations: 4
