S. Eren San

A novel approach for the determination of birefringence dispersion in nematic liquid crystals by using the continuous wavelet transform

Transmittance spectra of 5CB and ZLI-6000 coded nematic liquid crystals were acquired in the 12 600– 22 200 cm−1 region at room temperature. The continuous wavelet transform using the Morlet wavelet was applied to analyse the transmittance signal. Dispersion curves of the birefringence were obtained for 5CB and ZLI-6000 by this analysis and data were fitted to the Cauchy formula whereby the dispersion parameters were extracted. Results are found to be in favourable accordance with the published values.

Carbon Nanoparticles in Nematic Liquid Crystals

Fullerene C60, C70, single-walled and multi-walled carbon nanotubes and graphene sheets are doped to nematic liquid crystal (LC) host in the same percentage. Planar samples of these mixtures are prepared and our measurements constitute an optimization basis for possible applications. Fullerene balls are found to be the best compatible material for optical aims and reorientation of LC molecules, while the carbon nanotubes experience some reorientation possibility in LC media and graphene layers are good barriers to preserve reorientation.

TiO-Based Organic Hybrid Solar Cells with Mn

A hybrid solar cell is designed and proposed as a feasible and reasonable alternative, according to acquired efficiency with the employment of TiO2 (titanium dioxide) and Mn-doped TiO2 thin films. In the scope of this work, TiO2 (titanium dioxide) and Mn:TiO2 hybrid organic thin films are proposed as charge transporter layer in polymer solar cells. Poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (P3HT: PCBM) is used as active layer. When the Mn-doped TiO2 solar cells were compared with pure TiO2 cells, Mn-doped samples revealed a noteworthy efficiency enhancement with respect to undoped-TiO2-based cells. The highest conversion efficiency was obtained to be 2.44% at the ratio of 3.5% (wt/wt) Mn doping.