Nicoleta Preda

Dr. Nicoleta Preda

National Institute of Materials Physcics, Bucharest, Magurele, Romania

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 April 2021 in Nanomaterials
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Journal Article
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MSMarcela Socol
Marcela Socol
NPNicoleta Preda
Nicoleta Preda
Continuing growth in global energy consumption and the growing concerns regarding climate change and environmental pollution are the strongest drivers of renewable energy deployment. Solar energy is the most abundant and cleanest renewable energy source available. Nowadays, photovoltaic technologies can be regarded as viable pathways to provide sustainable energy generation, the achievement attained in designing nanomaterials with tunable properties and the progress made in the production processes having a major impact in their development. Solar cells involving hybrid nanocomposite layers have, lately, received extensive research attention due to the possibility to combine the advantages derived from the properties of both components: flexibility and processability from the organic part and stability and optoelectronics features from the inorganic part. Thus, this review provides a synopsis on hybrid solar cells developed in the last decade which involve composite layers deposited by spin-coating, the most used deposition method, and matrix-assisted pulsed laser evaporation, a relatively new deposition technique. The overview is focused on the hybrid nanocomposite films that can use conducting polymers and metal phthalocyanines as p-type materials, fullerene derivatives and non-fullerene compounds as n-type materials, and semiconductor nanostructures based on metal oxide, chalcogenides, and silicon. A survey regarding the influence of various factors on the hybrid solar cell efficiency is given in order to identify new strategies for enhancing the device performance in the upcoming years.

29 December 2018 in Coatings
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MSMarcela Socol
Marcela Socol
NPNicoleta Preda
Nicoleta Preda
Oana RasogaOana Rasoga
Oana Rasoga
ACAndreea Costas
Andreea Costas
ASAnca Stanculescu
Anca Stanculescu
Gabriel SocolGabriel Socol
Gabriel Socol
Indium tin oxide (ITO) thin films were grown on nanopatterned glass substrates by the pulsed laser deposition (PLD) technique. The deposition was carried out at 1.2 J/cm2 laser fluence, low oxygen pressure (1.5 Pa) and on unheated substrate. Arrays of periodic pillars with widths of ~350 nm, heights of ~250 nm, and separation pitches of ~1100 nm were fabricated on glass substrates using UV nanoimprint lithography (UV-NIL), a simple, cost-effective, and high throughput technique used to fabricate nanopatterns on large areas. In order to emphasize the influence of the periodic patterns on the properties of the nanostructured ITO films, this transparent conductive oxide (TCO) was also grown on flat glass substrates. Therefore, the structural, compositional, morphological, optical, and electrical properties of both non-patterned and patterned ITO films were investigated in a comparative manner. The energy dispersive X-ray analysis (EDX) confirms that the ITO films preserve the In2O3:SnO2 weight ratio from the solid ITO target. The SEM and atomic force microscopy (AFM) images prove that the deposited ITO films retain the pattern of the glass substrates. The optical investigations reveal that patterned ITO films present a good optical transmittance. The electrical measurements show that both the non-patterned and patterned ITO films are characterized by a low electrical resistivity (<2.8 × 10−4). However, an improvement in the Hall mobility was achieved in the case of the nanopatterned ITO films, evidencing the potential applications of such nanopatterned TCO films obtained by PLD in photovoltaic and light emitting devices.

13 May 2019 in ACS Applied Materials & Interfaces
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Journal Article
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MBMadalina Maria Barsan
Madalina Maria Barsan
Teodor Adrian EnacheTeodor Adrian Enache
Teodor Adrian Enache
NPNicoleta Preda
Nicoleta Preda
George StanGeorge Stan
George Stan
NANicoleta Georgiana Apostol
Nicoleta Georgiana Apostol
VDVictor Diculescu
Victor Diculescu

1 December 2020 in Scientific Reports
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NPNicoleta Preda
Nicoleta Preda
ACAndreea Costas
Andreea Costas
MBMihaela Beregoi
Mihaela Beregoi
NANicoleta Apostol
Nicoleta Apostol
AKAndrei Kuncser
Andrei Kuncser
IEIonut Enculescu
Ionut Enculescu
Biopolymers provide versatile platforms for designing naturally-derived wound care dressings through eco-friendly pathways. Eggshell membrane (ESM), a widely available, biocompatible biopolymer based structure features a unique 3D porous interwoven fibrous protein network. The ESM was functionalized with inorganic compounds (Ag, ZnO, CuO used either separately or combined) using a straightforward deposition technique namely radio frequency magnetron sputtering. The functionalized ESMs were characterized from morphological, structural, compositional, surface chemistry, optical, cytotoxicity and antibacterial point of view. It was emphasized that functionalization with a combination of metal oxides and exposure to visible light results in a highly efficient antibacterial activity against Escherichia coli when compared to the activity of individual metal oxide components. It is assumed that this is possible due to the fact that an axial p–n junction is created by joining the two metal oxides. This structure separates into components the charge carrier pairs promoted by visible light irradiation that further can influence the generation of reactive oxygen species which ultimately are responsible for the bactericide effect. This study proves that, by employing inexpensive and environmentally friendly materials (ESM and metal oxides) and fabrication techniques (radio frequency magnetron sputtering), affordable antibacterial materials can be developed for potential applications in chronic wound healing device area.

2 January 2020 in Materials
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IZIrina Zgură
Irina Zgură
NPNicoleta Preda
Nicoleta Preda
MEMonica Enculescu
Monica Enculescu
LDLucian Diamandescu
Lucian Diamandescu
CNConstantin-Catalin Negrila
Constantin-Catalin Negrila
MBMarcela-Elisabeta Barbinta-Patrascu
Marcela-Elisabeta Barbinta-Patrascu
In this work, ZnO–CdS composite powders synthesized by a simple chemical precipitation method were thoroughly characterized. The morphological, structural, compositional, photocatalytical, and biological properties of the prepared composites were investigated in comparison with those of the pristine components and correlated with the CdS concentration. ZnO–CdS composites contain flower-like structures, their size being tuned by the CdS amount added during the chemical synthesis. The photocatalytic activity of the composites was analyzed under UV irradiation using powders impregnated with methylene blue; the tests confirming that the presence of CdS along the ZnO in composites can improve the dye discoloration. The biological properties such as antioxidant capacity, antibacterial activity, and cytotoxicity of the ZnO, CdS, and ZnO–CdS composites were evaluated. Thus, the obtained composites presented medium antioxidant effect, biocidal activity against Escherichia coli, and no toxicity (at concentrations less than 0.05 mg/mL for composites with a low CdS amount) for human fibroblast cells. Based on these results, such composites can be used as photocatalytic and/or biocidal additives for photoactive coatings, paints, or epoxy floors, which in their turn can provide a cleaner and healthier environment.

8 August 2014 in Discover Nano
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Journal Article
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CFCamelia Florica
Camelia Florica
NPNicoleta Preda
Nicoleta Preda
MEMonica Enculescu
Monica Enculescu
IZIrina Zgură
Irina Zgură
MSMarcela Socol
Marcela Socol
IEIonut Enculescu
Ionut Enculescu
ZnO structures were deposited using a simple chemical bath deposition technique onto interdigitated electrodes fabricated by a conventional photolithography method on SiO2/Si substrates. The X-ray diffraction studies show that the ZnO samples have a hexagonal wurtzite crystalline structure. The scanning electron microscopy observations prove that the substrates are uniformly covered by ZnO networks formed by monodisperse rods. The ZnO rod average diameter and length were tuned by controlling reactants' concentration and reaction time. Optical spectroscopy measurements demonstrate that all the samples display bandgap values and emission bands typical for ZnO. The electrical measurements reveal percolating networks which are highly sensitive when the samples are exposed to ammonia vapors, a variation in their resistance with the exposure time being evidenced. Other important characteristics are that the ZnO rod networks exhibit superhydrophobicity, with water contact angles exceeding 150° and a high water droplet adhesion. Reproducible, easily scalable, and low-cost chemical bath deposition and photolithography techniques could provide a facile approach to fabricate such ZnO networks and devices based on them for a wide range of applications where multifunctionality, i.e., sensing and superhydrophobicity, properties are required.