Mirjana Dimitrievska

Mirjana Dimitrievska
École Polytechnique Fédérale de Lausanne | EPFL · Institute of Materials

34.2
 · 
Materials Scientist (PhD in Physics)

About

77
Publications
14,955
Reads
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1,207
Citations
Introduction
Physicist – Materials Scientist (PhD) with experience in exploration of structure-function relationships of new materials for advanced energy applications (photovoltaics, solid-state batteries, energy storage). Expert in Raman and neutron spectroscopy, x-ray and neutron diffraction (experimental and theoretical calculations). Optoelectronic characterization of semiconductor materials, with emphasis on defect and device properties.
Research Experience
June 2020 - present
École Polytechnique Fédérale de Lausanne
Position
  • Scientist
March 2016 - June 2019
National Institute of Standards and Technology
Position
  • PostDoc Position
March 2016 - June 2019
National Renewable Energy Laboratory
Position
  • PostDoc Position
Education
March 2013 - October 2015
University of Barcelona
Field of study
  • Physics of materials
October 2010 - October 2011
University of Novi Sad
Field of study
  • Physics of materials
October 2006 - October 2010
University of Novi Sad
Field of study
  • Physics

Publications

Publications (77)
Article
Full-text available
This work presents a complete analysis of all Raman active modes of Cu 2ZnSnS4 measuring with six different excitation wavelengths from near infrared to ultraviolet. Simultaneous fitting of spectra allowed identification of 18 peaks from device grade layers with composition close to stoichiometry that are attributed to the 27 optical modes theoreti...
Article
Phonon confinement effects in the Raman scattering spectra from polycrystalline Cu2ZnSnS4 thin films synthesized with different crystalline qualities – including photovoltaic grade layers – are investigated in terms of a phonon confinement model. Interpretation of the experimentally obtained spectra required the development of a modified model that...
Article
Full-text available
This work presents a detailed analysis of the impact of compositionally induced defects on the vibrational properties of Cu 2ZnSnSe4 absorbers for kesterite based solar cells. Systematic changes in the intensity of the E and B modes located around the 170, 220, and 250 cm−1 frequency regions, which involve mostly cation vibrations, were observed an...
Article
Full-text available
A comprehensive Raman resonance scattering study of ZnSxSe1-x (ZnSSe) solid solutions over the whole compositional range (0 ≤ x ≤ 1) has been made using 325 and 455 nm excitation wavelengths. The Raman scattering intensities of the LO ZnS-like and ZnSe-like phonon modes, corresponding to pure S and Se vibrations, respectively, are revealed to be si...
Article
Earth-abundant and low-cost semiconductors, such as zinc phosphide (Zn3P2), are promising candidates for the next generation photovoltaic applications. However, synthesis on commercially available substrates, which favors the formation of defects, and controllable doping are challenging drawbacks that restrain device performance. Better assessment...
Article
Full-text available
The mixed-anion solid-solution closo-carbahydroborate Na2(CB9H10)(CB11H12) shows the highest room-temperature ionic conductivity among all known solid Na-ion and Li-ion conductors, and the related nido-type carbahydroborate Na-7-CB10H13 exhibits superionic conductivity above the order-disorder phase transition temperature, ∼320 K. To study the Na-i...
Article
MCB11H12 (M: Li, Na) dodecahydro-monocarba-closo-dodecaborate salt compounds are known to have stellar superionic Li+ and Na+ conductivities in their high-temperature disordered phases, making them potentially appealing electrolytes in all-solid-state batteries. Nonetheless, it is of keen interest to search for other related materials with similar...
Article
Full-text available
The efficiency of kesterite-based solar cells is limited by various non-ideal recombination paths, amongst others by a high density of defect states and by the presence of binary or ternary secondary phases within the absorber layer. Pronounced compositional variations and secondary phase segregation are indeed typical features of non-stoichiometri...
Article
Metal borohydrides are considered promising materials for hydrogen storage applications due to a high volumetric and gravimetric hydrogen density. Recently, different Lewis bases have been complexed with Mg(BH4)2 in efforts to improve hydrogenation/dehydrogenation properties. Notably, Mg(BH4)2·xTHF adducts involving tetrahydrofuran (THF; C4H8O) hav...
Article
To investigate the dynamical properties of the novel hybrid compound, lithium benzimidazolate-borohydride Li2(bIm)BH4 (where bIm denotes a benzimidazolate anion, C7N2H5‒), we have used a set of complementary techniques: neutron powder diffraction, ab initio density functional theory calculations, neutron vibrational spectroscopy, nuclear magnetic r...
Article
Polycrystalline kesterite Cu2ZnSnSe4 (CZTSe) semiconductors have drawn attention as promising absorber candidates for the next generation of thin film photovoltaics. However, the narrow tolerance to stoichiometry variations, which favours the formation of secondary phases and cluster defects, is a challenging drawback that restrains the device perf...
Article
The hexagonal mixed-anion solid solution Na2(CB9H10)(CB11H12) shows the highest room-temperature ionic conductivity among all known Na-ion conductors. To study the dynamical properties of this compound, we have measured the ¹H and ²³Na nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation rates in Na2(CB9H10)(CB11H12) over the temper...
Article
In order to study the dynamical properties of cesium silanide CsSiH3, we have measured the 1H and 133Cs nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation rates in this compound over the temperature range of 5–354 K. The results of the 1H NMR measurements indicate that [SiH3]‒ anions in CsSiH3 retain unusually high reorientational...
Article
Full-text available
Quasielastic neutron scattering (QENS) measurements over a wide range of energy resolutions were used to probe the reorientational behavior of the pyramidal SiH3⁻ anions in the mono-alkali silanides (MSiH3, where M = K, Rb, and Cs) within the low-temperature ordered β-phases, and for CsSiH3, the high-temperature disordered α phase and intervening h...
Article
The ordered monoclinic phase of the alkali-metal decahydro-closo-decaborate salt Rb2B10H10 was found to be stable from about 250 K all the way up to an order-disorder phase transition temperature of ∼762 K. The broad temperature range for this phase allowed for a detailed quasielastic neutron scattering (QENS) and nuclear magnetic resonance (NMR) s...
Article
The disordered phases of LiCB11H12 and NaCB11H12 possess superb superionic conductivities that make them suitable as solid electrolytes. In these materials, cation diffusion correlates with high orientational mobilities of the CB11H12⁻ anions; however, the precise relationship has yet to be demonstrated. In this work, ab initio molecular dynamics a...
Article
The salt compounds NaB11H14, Na-7-CB10H13, Li-7-CB10H13, Na-7,8-C2B9H12, and Na-7,9-C2B9H12 all contain geometrically similar, monocharged, nido-undeca(carba)borate anions (i.e., truncated icosohedral-shaped clusters constructed of only eleven instead of twelve {B-H} + {C-H} vertices and an additional number of compensating bridging and/or terminal...
Article
This work presents a comprehensive analysis of the structural and vibrational properties of the kesterite Cu2ZnSnS4 (CZTS, I4̅ space group) as well as its polymorphs with the space groups P4̅2c and P4̅2m, from both experimental and theoretical point of views. Multiwavelength Raman scattering measurements performed on bulk CZTS polycrystalline sampl...
Article
The disordered phases of the 1-carba-closo-decaborates LiCB 9 H 10 and NaCB 9 H 10 exhibit the best solid-state ionic conductivities to date amongst all known polycrystalline competitors, likely facilitated in part by the highly orientationally mobile CB 9 H 10 – anions. We have undertaken both NMR and quasielastic neutron scattering (QENS) measure...
Article
Structural, vibrational, and dynamical properties of the mono- and mixed-alkali silanides (MSiH3, where M =K, Rb, Cs, K0.5Rb0.5, K0.5Cs0.5, and Rb0.5Cs0.5) were investigated by various neutron experiments, including neutron powder diffraction (NPD), neutron vibrational spectroscopy (NVS), neutron scattering fixed window scans (FWS) and quasielastic...
Article
Solid lithium and sodium closo-polyborate-based salts are capable of superionic conductivities surpassing even liquid electrolytes, but often only at above-ambient temperatures where their entropically driven disordered phases become stabilized. Here we show by X-ray diffraction, quasielastic neutron scattering, differential scanning calorimetry, N...
Article
The structure-dependent vibrational properties of different Mg(BH4)2 polymorphs (α, β, γ, and δ phases) were investigated with a combination of neutron vibrational spectroscopy (NVS) measurements and density functional theory (DFT) calculations, with emphasis placed on the effects of local structure and orientation of the BH4-anions. DFT simulation...
Article
Full-text available
Nanocrystalline Zn2SnO4 powders doped with Eu3+ ions were synthesized via a mechanochemical solid-state reaction method followed by post annealing in air at 1200 oC. X-ray diffraction (XRD), energy-dispersive X-ray (EDX), Raman and photoluminescence (PL) spectroscopies provide convincing evidence for the incorporation of Eu3+ ions into the host mat...
Article
We present structural and optical spectroscopy studies of thin films of Cu2ZnSnSe4 (CZTSe) with strong copper deficiency deposited on Mo/Glass substrates and selenised at 450, 500 or 550 °C. Solar cells fabricated from these films demonstrated efficiencies up to 7.4% for selenisation at 500 °C. Structural analysis based on X-ray diffraction and Ram...
Article
Cu2ZnSnSe4 (CZTSe) is a promising thin film photovoltaic absorber material. However, up to now its main problem is the low open circuit voltage (Voc) compared to more mature thin film photovoltaic technologies. Most kesterite synthesis routes employ a two-step approach consisting of precursor deposition followed by a crystallization step. In this s...
Article
Full-text available
Microstructural properties of Cu2ZnSn(SxSe1−x)4 kesterite solid solutions were investigated using grazing incidence X-ray diffraction for the full interval of anion compositions in order to explore the influence of S and Se atoms on the thin film morphology. Thin films were prepared by sputtering deposition of metallic precursors, which were then s...
Article
Kesterite thin films solar cells have been studied in recent years as a potential earth abundant alternative to other thin film technologies such as the ones based on the chalcopyrite Cu(In,Ga)Se2 (CIGS). However, the efficiency of the kesterite devices is still low and needs further development. In order to increase the performance of the kesterit...
Article
Monodisperse Cu2ZnSnS4 (CZTS) nanocrystals, with quasi-spherical shape, were prepared by a facile, high yield, scalable and high concentration heating-up procedure. The key parameters to minimize the nanocrystal size distribution were efficient mixing and heat transfer in the reaction mixture through intensive argon bubbling and improved control of...
Article
In this work we report on the effect of alkali doping via Na and/or K introduction into flexible and light-weight Cu2ZnSnSe4 (CZTSe) solar cells obtained using a sequential process based on the sputtering of metallic stacks and further reactive annealing. Different thicknesses of Cr diffusion barriers and 50 μm thick ferritic steel substrates were...
Thesis
Full-text available
The main objective of this thesis is to deepen the knowledge of fundamental properties of kesterite materials (Cu2ZnSnS4 and Cu2ZnSnSe4) and their solid solutions Cu2ZnSn(S,Se)4, which are used as absorber layers in solar cells. This principally included full characterization of structural and vibrational properties of these materials mainly using...
Article
Heterojunction zinc tin oxide (ZnO/SnO2) nanoparticles were prepared using a top–down traditional solid–state method; mechanical grinding followed by annealing, and characterized by X-ray diffraction, multi-wavelength excitation Raman scattering, scanning electron microscopy, diffuse reflectance and photoluminescence spectroscopy. The photocatalyti...
Article
Kesterite thin films solar cells have been studied in recent years as a potential earth abundant alternative to other thin film technologies such as the ones based on the chalcopyrite Cu(In,Ga)Se2 (CIGS). However, the efficiency of the kesterite devices is still low and needs further development. In order to increase the performance of the kesterit...
Article
Full-text available
In order to deepen in the knowledge of the vibrational properties of 2-dimensional MoS2 atomic layers, a complete and systematic Raman scattering analysis has been performed using both bulk single crystal MoS2 samples and atomically thin MoS2 layers. Raman spectra have been measured under non-resonant and resonant conditions using seven different e...
Article
Cu 2 ZnSnSe 4 solar cell absorbers are synthesized by large-area electrodeposition of metal stack precursors followed by selenization. A champion solar cell exhibits 8.2% power conversion efficiency, a new record for Cu 2 ZnSnSe 4 solar cells prepared from electrodeposited metallic precursors. Significant improvements of device performance are achi...
Article
Quaternary Cu2ZnSn(S1-xSex)4 compounds are promising semiconductor materials for absorber layer in thin film solar cells. Record efficiency devices (12.6%) exhibit an off-stoichiometric composition of the absorber layer. These deviations from stoichiometry cause intrinsic point defects, which determine the electronic properties of the semiconductor...
Article
Full-text available
Utilizing a combinatorial approach, two distinct compositions for optimizing optoelectronic properties are found for Cu2ZnSnSe4-based solar cells, due to formation of different defect clusters, secondary phases, and potentially other composition related effects. One of the highest open circuit voltages for this compound is reported, as well as a na...
Article
Full-text available
Cu2ZnSnS4 (CZTS) is a promising material for photovoltaic and thermoelectric applications. Issues with quaternary semiconductors include chemical disorder (e.g., Cu–Zn antisites) and disproportionation into secondary phases (e.g., ZnS and Cu2 SnS 3). To provide a reference for the pure kesterite structure, we report the vibrational spectra—includin...
Article
Full-text available
In this work, Raman spectroscopy and X-ray diffraction were applied together to evaluate the crystal structure and the phonon modes of photovoltaic grade Cu 2ZnSn(SxSe1−x)4 thin films, leading to a complete characterization of their structural and vibrational properties. Vibrational characterization has been based on Raman scattering measurements p...
Article
Solar cells based on Cu2ZnSnSe4 thin film absorber layers have shown promise as an alternative to more mature thin film technologies because they are composed of more earth abundant elements. To increase device efficiencies there is still much to be investigated about its properties, and film and device processing. Rapid thermal processing is a mor...
Article
Full-text available
In this work we report the Cu doping of chemical bath deposited CdS for the preparation of Cu2ZnSnSe4/CdS:Cu hetero-junction. We demonstrate that increasing the Cu concentration in the reaction bath several fundamental properties of CdS are changed (optical, crystalline, morphological), positively impacting in the resulting devices. The improvement...
Article
Full-text available
We report a compositional paradigm in kesterite compounds, where VOC and JSC must be optimized independently from point of view of composition. Device-grade Cu2ZnSnSe4 thin films in solar cells are characterized by non-stoichiometric compositions. The reason for such a broad range is not entirely understood, and a precise “ideal” composition is not...
Article
Full-text available
As the interest in Cu2ZnSn(SxSe1−x)4 (0 ≤ x ≤ 1) kesterite based thin film solar cells increases, the development of new processes and characterization methodologies are required to satisfy its own peculiarities. In order to achieve better device performance and higher efficiencies a detailed systematic study of the fundamental properties of these...
Conference Paper
Full-text available
Optimized conditions for conventional thermal processing of Cu2ZnSnSe4 are not readily transferable to the rapid thermal processing, though it is of high importance to test the industrial viability of this material. Here the effect of layer order has been investigated for Cu-Zn(O)-Sn precursor stacks selenized by rapid thermal processing to form Cu...
Conference Paper
In this study we report the effects of different structural and microstructural properties on optoelectronic characteristics of CZTSe thin films synthesized by DC-magnetron sputtering deposition and annealed in a Se containing atmosphere. CZTSe samples with different properties were obtained by varying the cationic ratios, Cu/(Zn+Sn) and Zn/Sn, in...
Conference Paper
Higher efficiency Cu2ZnSnS4 (CZTS) based solar cells have been based on absorbers synthesized under Cu-poor and Zn-rich compositions in order to avoid the formation of Cu-S and Cu-Sn-S secondary phases, and favor VCu vacancy defects. Raman spectroscopy has demonstrated its potential as a characterization tool for CZTS, allowing the detection of the...
Article
Mg-doped ZnO nanocrystallites were prepared via conventional solid-state reaction when ZnO and MgO precursors were stoichiometrically mixed and heated at 700 °C, 900 °C and 1100 °C for 2 h in air atmosphere. Influence of annealing temperature on structural and optical properties of the obtained nanoparticles was investigated using X-ray diffraction...
Article
Full-text available
Zinc oxide nanoparticles doped with europium were obtained by high energy ball milling followed by heat treatment and combustion reaction synthesis method starting from its microcrystalline powders. The influence of the preparation method approach and europium doping on the structural and optical properties of ZnO powders was investigated by X-ray...