جستجوی مقالات مرتبط با کلیدواژه "electro-optical properties" در نشریات گروه "علوم پایه"

In this research, we use first-principles calculations based on density functional theory (DFT) to investigate the electro-optical performance of a three-dimensional T-carbon nanostructure. In addition to analyzing the dynamic and static stability of the optimized structure of the T-carbon unit cell, as new research, the electro-optical properties of T-carbon, under the effect of omnidirectional hydrostatic stress on the unit cell up to 9 GPa, were simulated by using computational codes. The obtained results indicate the acceptable performance of this nanostructure as a suitable optical absorbent material. This three-dimensional nanostructure can be used to design innovative components such as electro-optical sensors, light intensifiers, optical detectors, and organic perovskite solar cells.

In this study, ZnCdTeS quantum dots (QDs) with luminescent properties at different emission wavelengths were utilized to enhance the dielectric and electro-optical characteristics of nematic liquid crystal (NLC) cells. At various temperatures, the dielectric permittivity components (ɛ‖ and ɛꓕ) and dielectric anisotropy (Δɛ) of NLC samples containing ZnCdTeS QDs were measured. ɛ‖ increases considerably more than ɛꓕ in the nematic phase when QDs are introduced. The dielectric anisotropy of the system has increased by approximately 19% in the presence of QDs with red emission, which is a result of a significant enhancement of ɛ‖. The NLC environment induces one-dimensional arrays of QDs in the system, which enhances the dielectric properties of the system, as demonstrated by the dielectric results. The electro-optical findings indicate that including QDs substantially reduces the threshold voltage of NLC cells. Incorporating quantum dots into liquid crystal led to a reduction in the threshold voltage from 2.57 V for pure NLC to 2.21 V. QDs improve the effective field of a system by reducing the screening effects caused by ionic impurities in the system. Anisotropy enhancement, effective field increase within the cell, and QD-NLC interaction improvement all contribute to the enhancement of the cell's switching characteristics.

 In this research, the electro-optical aspects of Tetra-Hexagonal-Carbon allotrope as a two-dimensional nanostructure under compressive buckling parameter based on density functional theory (DFT) with PBE-GGA full potential approximation method using simulation software and computational codes based on first-principles calculations have been investigated. The analysis of the results obtained from the calculations of the electronic properties of this nanostructure, such as the band gap and density of states (DOS) under buckling change, indicates that the energy band gap of this nanosheet as a direct band gap semiconductor with 1.61 eV, increases slightly under the influence of the compressive buckling factor and then decreases down to 1.11 eV by applying higher compressive buckling factors. The optical properties of this nanosheet have smooth and regular changes in the out-of-plane polarization, by applying compressive buckling conditions in the visible light spectrum. Also, according to the obtained results, an acceptable match between the electronic and optical properties of this two-dimensional nanostructure is observed, which indicates the correspondence of electronic and optical behaviors, which can predict this carbon nanosheet is a suitable material for designing electro-optical devices.

In this experimental work, electro-optical properties of Al2O3 nanoparticles doped 5CB liquid crystal was investigated. Therefore, Alumina nano powder was synthesized using precipitation method then homogenously oriented samples with different percentage of nanoparticles prepared and birefringence and threshold voltage of them were measured. Also, rise and relaxation time of samples were studied.It was seen that birefringence of samples with 0.1 and 0.3 percent nanoparticles considerably increase respect to undoped liquid crystal.