جستجوی مقالات مرتبط با کلیدواژه « optical properties » در نشریات گروه « ریاضی »

Functional dye is a new term in the field of dye chemistry which has been specifically designed for high-technology applications such as solar cells, photochromic dyes, liquid crystal, electrophotography, fluorescent sensors and photodynamic therapy. BODIPY and its derivatives as organic fluorophores have optical properties and can be used as potential sensors in various applications for biotechnological, industrial and medical purposes. In this research, a group of a new fluorescent indicators based on BODIPY structure were designed which have been composed from two seven-membered rings including Al or B atoms that has been connected with methine bridge complexed with NH2 or PH2 center. The geometries, optical properties and electronic structures of various designed molecules were studied using time-dependent density functional theory (TDDFT). The results of the calculations showed that the new designed structures are stable and highly optically active with considerable quantum yield (Φ) absorption and emission as if is promising candidates for hi-tech different applications.

The dye extracted from the plant is already well used in optoelectronic applications for its easy and safe handling. This study is to demonstrate the effect of magnetized distilled water on dye extracted from Anchusa-Italica flowers. The results of its optoelectronic behavior reveal that the use of magnetized water in the extraction process results in different and better properties than processes in which ordinary water was used. The structural analysis of Anchusa-Italica dye thin-film was performed using the Fourier-transform infrared technique (FT-IR). The optical responses, such as the absorption coefficient, absorption spectra, both standard and refractive indices, and electronic properties (optical energy gap) were studied using Ultraviolet-Visible transmittance spectra range 300–900 nm. The calculated energy band gap of the dye extracted using magnetized water was decreased from 3.23 to 2.35 eV and turned into the preferred direct band gap to make a useful contribution to optical sources. The optical absorption spectra of the dye extracted using magnetized water appear to have a better efficiency compared to that extracted with ordinary water. A significant evolution in the absorption coefficient was obtained by employing magnetized water to extract the dye. The magnetized extraction process also modified the electronic transmission values (indirect to direct). The effect of magnetized water on the resonance mode and transparent indication was deduced by studying the complex refractive index. An increase appeared in the spectrum of the absorption index at a wavelength of 570 nm, whereas a small attenuation coefficient was observed as well. The important effects of magnetized dye extraction will highly benefit the field of optoelectronic applications.

Silicon thin layers are deposited on glass substrates with the thickness of 103 nm, 147 nm and 197 nm. The layers are produced with electron gun evaporation method under ultra-high vacuum condition. The optical Reectance and the Transmittance of produced layers were measured by using spectrophotometer. The optical functions such as, real and imaginary part of refractive index, real and imaginary part of dielectric constant, real and imaginary part of conductivity, absorption coeficient and optical band gap energy are calculated basing on the Kramers-Kronig relations. The void fractions of the silicon lms are calculated by using Aspnes theorem. The effect of layer thickness on optical properties of silicon thin lms is investigated.