National Institute Of Materials Physics - Romania

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5781 articles found

1561. MEASUREMENT OF CHARGE CARRIER MOBILITY IN PEROVSKITE NANOWIRE FILMS BY PHOTO-CELIV METHOD

Authors: Aukstuolis, A; Girtan, M; Mousdis, GA; Mallet, R; Socol, M; Rasheed, M; Stanculescu, A

Published: JAN-MAR 2017, PROCEEDINGS OF THE ROMANIAN ACADEMY SERIES A-MATHEMATICS PHYSICS TECHNICAL SCIENCES INFORMATION SCIENCE, 18, 41, DOI:

In this paper the holes' mobility for the configuration FTO/TiO2/CH3NH3PbI3/SpiroMeOTAD/Au was measured for the first time by the Photo-CELIV method. The TiO2 dense film was deposited by reactive sputtering at room temperature on FTO glass substrates. High crystalized perovskite films were deposited from solutions in one step by spin coating. Spiro-MeOTAD molecular glass was used as holes transporting layer. The highest holes' mobility from TiO2 thin film through the perovskite and Spiro MeOTAD film to the top gold electrode was of Order 8.5x10(-7) cm(2)/Vs.

1562. PHOTOACTIVITY OF HEMATITE ELECTRODE PREPARED VIA ANODIC ELECTRODEPOSITION ON FTO AND FTO/TiO2 SUBSTRATES

Authors: Sima, M; Vasile, E; Sima, MA

Published: JUL-SEP 2017, DIGEST JOURNAL OF NANOMATERIALS AND BIOSTRUCTURES, 12, 758, DOI:

The hematite films were prepared via anodic electrodeposition on FTO and FTO/mesoporous TiO2 substrates. The hematite photoanodes were characterized by X-ray diffraction and scanning electron microscopy. The performance of the prepared hematite photoanodes was assessed based on photocurrent-voltage curves and electrochemical impedance spectra. The modification of the hematite surface with nickel oxide nanoparticles improved the performance of the hematite photoanode while phosphorous doped hematite photoanode shows poor photoactivity. The onset of water oxidation photocurrent was cathodically shifted for hematite photoanodes prepared on FTO/TiO2 substrate.

1563. MAPLE DEPOSITION OF PLGA MICROSPHERES FOR MEDICAL APPLICATIONS

Authors: Fufa, O; Socol, M; Preda, N; Grigorescu, S; Croitoru, S; Socol, G

Published: JAN-MAR 2017, DIGEST JOURNAL OF NANOMATERIALS AND BIOSTRUCTURES, 12, 80, DOI:

The aim of our study was to synthesize and evaluate the physicochemical and biological properties of composite films based on poly(lactic-co-glycolic acid) copolymer and quercetin (PLGA/Q) microspheres. During our experiments, we firstly synthesized the PLGA/Q microspheres by using an oil-in-water emulsion-diffusion-evaporation method. Subsequently, the as-prepared composite material was subjected to the matrix assisted pulsed laser evaporation (MAPLE) technique, in order to obtain the PLGA/Q coatings. Relevant compositional and microstructural features of the synthesized samples were obtained by means of Fourier transform infrared spectroscopy (FTIR) and AFM (atomic force microscopy). The long-term biocompatibility of the synthesized films was in vitro evaluated by cellular viability and immunofluorescence assays.

1564. Epitaxial La0.67Ba0.33Ti0.02Mn0.98 O-3 oxide thin films

Authors: Marouan, O; Galca, AC

Published: 2017, ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES, 73, C222, DOI: 10.1107/S2053273317093512

1565. Applications of DNA-Electrochemical Biosensors in Cancer Research

Authors: Chiorcea-Paquim, AM; Oliveira, SCB; Diculescu, VC; Oliveira-Brett, AM

Published: 2017, PAST, PRESENT AND FUTURE CHALLENGES OF BIOSENSORS AND BIOANALYTICAL TOOLS IN ANALYTICAL CHEMISTRY: A TRIBUTE TO PROFESSOR MARCO MASCINI, 77, 336, DOI: 10.1016/bs.coac.2017.06.003

1566. Pinning-Engineered YBa2Cu3Ox Thin Films

Authors: Mele, P; Crisan, A; Adam, MI

Published: 2017, VORTICES AND NANOSTRUCTURED SUPERCONDUCTORS, 261, 63, DOI: 10.1007/978-3-319-59355-5_2

1567. Characterization of MAPLE deposited WO3 thin films for electrochromic applications

Authors: Boyadjiev, SI; Stefan, N; Szilagyi, IM; Mihailescu, N; Visan, A; Mihailescu, IN; Stan, GE; Besleaga, C; Iliev, MT; Gesheva, KA

Published: 2017, INERA WORKSHOP 2016: MEMBRANE AND LIQUID CRYSTAL NANOSTRUCTURES (MELINA 2016), 780, DOI: 10.1088/1742-6596/780/1/012013

Tungsten trioxide (WO3) is a widely studied material for electrochromic applications. The structure, morphology and optical properties of WO3 thin films, grown by matrix assisted pulsed laser evaporation (MAPLE) from monoclinic WO3 nano-sized particles, were investigated for their possible application as electrochromic layers. A KrF* excimer (lambda = 248 nm, .zeta(FWHM)=25 ns) laser source was used in all experiments. The MAPLE deposited WO3 thin films were studied by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD) and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetry measurements were also performed, and the coloring and bleaching were observed. The morpho-structural investigations disclosed the synthesis of single-phase monoclinic WO3 films consisting of crystalline nano-grains embedded in an amorphous matrix. All thin films showed good electrochromic properties, thus validating application of the MAPLE deposition technique for the further development of electrochromic devices.

1568. Shiba States Coupled to a Resonant Cavity

Authors: Chirla, R; Horea, CD; Costea, TO; Dragomir, R; Manolescu, A; Moca, CP

Published: 2017, TIM15-16 PHYSICS CONFERENCE, 1796, DOI: 10.1063/1.4972367

When a quantum dot is embedded into a superconducting environment, it leads to the formations of localized Shiba states inside the gap. If the Coulomb interaction is sufficiently small, the Shiba states consist of a pair of singlet states and a doublet, that compete for the ground state and induce a quantum phase transition. In the presence of an external microwave field, the Shiba energy spectrum is significantly modified. Moreover, the transmission of the cavity inherits features that can pinpoint the exact location of the quantum critical point. In terms of methods used, our analytical calculations are supplemented by state of the art numerical renormalization group calculations.

1569. MORPHOLOGICAL AND OPTICAL PROPERTIES OF ELECTROSPUN SnO2 FIBERS

Authors: Busuioc, AD; Ciovica, I; Stoleriu, S; Enculescu, M; Evanghelidis, A; Visan, T

Published: OCT-DEC 2017, DIGEST JOURNAL OF NANOMATERIALS AND BIOSTRUCTURES, 12, 1105, DOI:

The electrospinning technique was employed for the preparation of SnO2 fibers starting from a precursor solution consisting of a tin salt, polyvinylpyrrolidone as carrier polymer and N,N-dimethylformamide as dispersion medium. In order to achieve single-phase crystalline structures, the as-spun fibers were calcined at 500, 700 or 900 degrees C, with two different heating rates of 1 or 10 degrees C/min. The thermally treated samples were characterized in terms of structure, morphology and bandgap by employing X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and UV-Vis spectroscopy. A fine tuning of the bandgap width was attained through the selection of different values for the electrospinning and calcination parameters.

1570. Photosensitive GeSi/TiO2 multilayers in VIS-NIR

Authors: Palade, C; Dascalescu, I; Slav, A; Lepadatu, AM; Lazanu, S; Stoica, T; Teodorescu, VS; Ciurea, ML; Comanescu, F; Muller, R; Dinescu, A; Enuica, A

Published: 2017, 2017 INTERNATIONAL SEMICONDUCTOR CONFERENCE (CAS), 40TH EDITION, 70, DOI:

The electrical and photosensing properties correlated with structure and morphology of TiO2/(GeSi/TiO2)(2) multilayers are investigated. The multilayers are prepared by magnetron sputtering followed by rapid thermal annealing. Studies of Raman spectroscopy, transmission electron microscopy and X-ray diffraction are carried out. Measurements of dark current versus voltage and temperature are done. The photosensing properties are studied by measuring photocurrent spectra at different temperatures. We obtain multilayers with 10 - 15 nm Ge0.6Si0.4 nanocrystals (NCs) by annealing at 800 degrees C. We evidence the tunneling mechanism between neighbor NCs (T-1/2 law) in the dark current-temperature dependence. The photocurrent spectrum has a maximum with position shifting from 940 to 980 nm when the measurement temperature increases from 150 to 300 K, being due to the GeSi NCs.