Stage 1 - P2 2016
The project implementation schedule
Phase no. 1
Responsible: Dr. Felix SIMA
Title: "Ordered mesoporous carbon obtained by laser irradiation of polymeric precursor solutions"
Abstract: With this project the synthesis of carbon based materials by a novel “soft-template” laser assisted method is proposed. This innovative and eco-friendly process is based on pulsed laser irradiation of liquid solutions consisting of carbon based natural compounds (plant extracts precursors). It thus aims the synthesis of carbon based hierarchical materials from polymeric templates with different chain lengths which can induce pore formation with various pore sizes. The laser treatment (irradiation) influences the porosity and structure of carbon at micro- and nano-scale and, eventually, will improve electronic conductivity, a fundamental characteristic in numerous domains. These performances will further be developed by adding hetero-atoms such as N and O or other metallic nanoparticulate compounds. The originality is given by the implementation of laser processing assisted methods applied to synthesis of ordered carbon materials. The methods were not explored before for the proposed materials and, as consequence, the study represents a real challenge for the development of carbon materials with different morphological and structural properties with applications in hot-topic domains such as energy storage or drug delivery systems.
Phase no. 2
Responsible: Dr. Angela STAICU
Title: "Obtaining and characterisation of lasing type radiation emited by liquide microdroplets containing laser dye solutions"
Abstract: It was obtained and characterized the lasing radiation emited by pendant microdroplets containing Rhodamine 6G laser dye-doped aqueous solutions. Droplets with volumes of microliter order of magnitude were generated with a computer-controlled dispenser from stock solutions of Rhodamine 6G in ultrapure water at concentrations varying between 10-5 M and 10-3 M. The optical pumping of the microdroplets was performed with the second harmonic (SHG, 532 nm wavelength) of a pulsed Nd:YAG laser (pulse width at half maximum of 6 ns, repetition rate of 10 pps). Also, the pamping energy was varied between 6 mJ and 18 mJ. The features of the emitted radiation (wavelength, bandwidth, intensity) were analyzed according to the set droplet volume, dye concentration, pumping energy, and the collection geometry of radiation.
Phase no. 3
Responsible: Dr. Eniko GYORGY
Title: "Physico-chemical characterization of composite nanomaterials based on transition metal oxides and carbon nanoparticles synthesized by laser technique"
Abstract: The main objective of this project is to significantly improve the photocatalytic activity of composite materials based on transition metal oxides and carbon nanoparticles. The proposed laser methodology allows the reduction and doping of carbon nanoparticle, deposition of crystalline nanostructures and creation of porous carbon structures. It is expected that all these effects contribute to the improvement of the photocatalytic process efficiency.
Titanium oxide (TiO2) is an extensively investigated semiconductor material, due to its outstanding properties such as chemical and thermal stability, earth abundance, low cost, and biological inertness. Owing to its high photoactivity, TiO2 shows great potential for environmental applications such as solar energy conversion and storage, or photocatalytic dissociation of organic compounds for waste-water treatment, disinfection, as well as air purification. Moreover, TiO2 surfaces are hydrophobic. As known, on hydrophobic surfaces water droplets flow freely and contaminants are carried along, being washed away. As a consequence, coating of materials surfaces with hydrophobic water-repellent layers endows them valuable self-cleaning properties, required for many application fields as for example windows, microfluidics, photovoltaics, biomedical devices, and anti-bacterial surfaces and textiles.
On the other hand, carbon-based nanomaterials could convey also additional functionality to the hydrophobic TiO2 surface, as improved electrical conductivity. It is known, that surface electroconductivity is important in environmental self-cleaning applications. Previous investigations demonstrate that highly conductive surfaces avoid adsorption of organic contaminants by antistatic effect.
It has been shown that synthesis of nanocomposites based on TiO2 with different dopants such as noble metals, anions, carbon nanomaterials lead to improved photocatalytic efficiency of TiO2 surfaces. Highly conductive and hydrophobic TiO2-reduced graphene oxide-silver nanocomposite coatings were prepared by simple one-step environmentally friendly matrix assisted pulsed laser evaporation (MAPLE) laser technique.
Phase no. 4
Responsible: Dr. Andreea GROZA
Title: "Interface nanometric layers for increase of the coatings adhesion"
Abstract: In this report are presented the data obtained as a result of polymer layers generation in corona discharges at atmospheric pressure in a multi-point to - plane electrode configuration, in order to use them as interface layers for different type of coatings. Polymer layers were analyzed by complementary techniques such as glow discharge optical emision spectroscopy, GDOES, Fourier transform infrared spectroscopy, FTIR spectroscopy, X-ray photoelectron spectroscopy, XPS, and scanning electron microscopy, SEM. By using these polymers (polydimethylsiloxane) as interface layers was analyzed their influence on the physico-chemical properties and morphology of hydroxiapatite doped with zinc (Zn:HAP) coatings and their role in Zn:HAp adherence to the substrate.
Phase no. 5
Responsible: Dr. Florian DUMITRACHE
Title: "Sinteza prin piroliza laser de nanoparticule bimetalice pe baza de fier"
Phase no. 6
Responsible: Dr. O. TOMA
Title: "Methods for the spectroscopic characterization of optically scattering materials (nanopowders, ceramics) doped with rare - earth ions"
Abstract: Ceramic samples (pellets) of the partially-disordered crystalline material known as langatate (La3Ga5,5Ta0,5O14, LGT), doped with 3 at.% erbium , were synthesized by solid-state reaction. The samples were cut into thin slices (0.24 mm) to reduce as much as possible the effects of light scattering on the optical spectra of Er3+.
Excited-state absorption spectra were obtained (for the first time in scattering media), in the spectral range 400 - 750 nm, using a double-modulation scheme, with the pump beam supplied by a laser diode emitting at 978 nm. The spectra were calibrated using the ground-state absorption spectrum (previously calibrated using the Judd-Ofelt formalism extended to light-scattering media) and separated from the contribution of the stimulated emission and luminescence. These contributions are experimentally put into evidence in the recorded spectra. For their separation and the calibration of spectra, a simple mathematical model that takes into account the contribution of luminescence to the obtained spectra was proposed.
The various transitions present in the measured spectra were identified and discussed; the most numerous and intense transitions are those originating on 4I13/2; for these, the absorption cross-sections could be obtained with precision. The 4I11/2 level is much less populated, and the absorption processes originating on it and can be put into evidence in experiment are few and of negligible intensity.