Cosmina Andreea Lazar

Novel materials based on DNA‐CTMA and lanthanide (Ce3+, Pr3+)

New, deoxyribonucleic acid (DNA) based compounds, functionalized with hexadecyltrimethylammonium chloride (CTMA) and lanthanide hydroxide nanoparticles were synthesized. The spectral measurements suggest that between the DNA-CTMA complex and the lanthanide (III) ions a chemical interaction takes place. The obtained materials exhibit an improved fluorescence efficiency, showing a potential interest for application in photonics, and more particularly, in light emitting devices.

Chromophore influence on DNA compactisation (Conference Presentation)

Our recent research results showed that DNA chains undergo a compactisation when DNA solutions are doped with different chromophores. In this paper we will present our attempt to model this behaviour in order to predict the DNA solutions characterisation.

Dynamical light scattering for DNA-CTMA:DR1 chains: wormlike semi-flexible model, coil size and persistence length

Recent experimental Dynamic Light Scattering (DLS) studies of the coil sizes of DNA-CTMA:Rh solutions have lead to numerical discrepancies with theoretical predictions amounting to one-two orders of magnitude.1 In this paper, which has partially character of a tutorial, we present the basic theoretical concepts underlying an analysis of the polymer coil sizes from DLS experiments. In particular, we discuss the limitations of those methods. We present a wormlike model of a polymer chain which is a promising candidate for inferring information about the spatial structure of the DNA chain from experimental data.

Linear and nonlinear optical properties of new materials based on DNA-CTMA and aromatic compounds (Conference Presentation)

In order to find eco-friendly materials for different applications an important research effort was devoted to the materials science in the last decade. A particular attention attracted the deoxyribonucleic acid (DNA). The interest is due to its versatility, biodegradability, abundance and their origin from renewable sources. DNA based new materials, functionalized with hexadecyltrimethylammonium chloride (CTMA) and aromatic compounds were prepared. Solutions with two different concentrations of aromatic compounds were obtained in butanol. The obtained, new complexes were processed into good optical quality thin films by spin coating method. Films were deposited on glass substrates and characterized for their spectroscopic, linear and nonlinear optical properties. The third-order nonlinear optical (NLO) properties of thin films were determined by the optical third-harmonic generation technique at 1 064.2 nm fundamental wavelength. The obtained materials, with improved fluorescence efficiency, present a potential interest for application in photonics.

Tunning the Colour of Solar Absorbers by Changing Chromophore Nature and Nanoparticle Size

In this paper some metallic (Au) and oxide (NiO and Cr2O3) nanoparticle dispersions are proposed as optical enhancers for solar collectors. The metallic nanoparticles are synthesised by photoreduction technique whereas the oxide nanoparticles are obtained by precipitation method, their shape and size being confined in a template of water-in-oil microemulsion. By using the mentioned template, monodispersed nanoparticles could be prepared, which have been further characterized by dynamic light scattering, transmission electron microscopy, diffuse reflectance spectroscopy and chromatic analysis. Correlation of these results is useful to obtain criteria for the design of Au or metallic oxides nanoparticles based solar absorbers.