The widespread application of laser devices requires development of new protections against light pulses of high intensity. This problem is relevant because of the danger of hitting the civil aviation pilots with bright and powerful radiation originating from the laser sources which are widely used in the everyday life. Therefore, this work is devoted to continuing our research on a new class of macroheterocyclic compounds – thermally and chemically stable J-type phthalocyanine dimers as potential nonlinear absorbers for optical limiting technology. The dimeric complexes of magnesium (1a) and zinc (1b) were covalently bonded to single-walled carbon nanotubes (SWCNTs) to improve the overall characteristics of the potential optical limiters 2a,b as compared to the previously studied corresponding dyes in solutions. The conjugates obtained were investigated using atomic force microscopy (AFM), as well as Raman and IR spectroscopy to confirm formation of the covalent binding of phthalocyanine macrocycles with the carbon surface. Open-aperture Z-scan and a fixed limiter location experiments have demonstrated low values of the limiting threshold and high degree of attenuation of the input laser radiation with the pulses duration located in the nanosecond range.

Conjugates of thermally stable phthalocyanine J-type dimers with single-walled carbon nanotubes for enhanced optical limiting applications

New Entries to 3-Acylchromones: TM-Catalysed Decarboxylative Cross-Coupling of α-Keto Acids with ortho-Hydroxyarylenaminones, 2,3-Unsubstituted Chromones and 3-Iodochromones

A facile and versatile procedure for the synthesis of functionalized novel 2,5-diphenyl-5H-chromeno[4,3-d]pyrimidin-5-ol and (2,4-diphenylpyrimidin-5-yl) (2-hydroxyphenyl) methanone has been described. The key step in the synthesis involves the ANRORC reaction of 3-benzoyl chromones with benzamidines.

Synthesis of novel fused chromone–pyrimidine hybrids and 2,4,5-trisubstituted pyrimidine derivatives via ANRORC rearrangement

The third-order susceptibility and second-order hyperpolarizability and the two-photon absorption coefficient of Eosin-B in AOT/water/Heptane were investigated by using the Z-Scan technique. The droplets were prepared with an AOT/water droplet in a continuous phase of Heptane. The droplets size changes with the amount of water and the droplet concentration decreases with the increase of Heptane concentration. To study the nonlinear optical properties of Eosin-B, the Z-scan measurements were performed by means of a laser at 532 nm and 80 mW power. The nonlinear refractive and the nonlinear absorption coefficient indices were found to be in the order of 10−12 (cm2 W−1) and 10−7 (cm W−1), respectively. The change of nonlinear optical properties of Eosin-B by droplet size and concentration is due to the change of dye aggregation and thermal conductivity and thermo-optic coefficient of samples. The absorption of Eosin-B changes with the polarity of the medium (dielectric constant and refractive index). It has been shown that the intensity of emission spectra of Eosin-B in AOT/water/Heptane is enhanced compared to that of aqueous solution. By the Bilot and Kawski theory, the ratio between the excited state and the ground state of the dipole moments (μe/μg) of Eosin-B both in water and in droplets is extracted.

Solvatochromic and nonlinear optical properties of Eosin B in solvents and AOT/water/Heptane

In this work, we report on the tuning of the optical transmission properties of the graphene oxide liquid crystal. The proposed tuning method is obtained by irradiating the liquid crystal samples with 532-nm laser irradiation. For this purpose, liquid crystallinity of the graphene oxide is proved by the birefringence measurement method. Large nonlinear absorption has been observed from graphene oxide liquid crystals. Open-aperture Z-scan experiments revealed that the laser irradiation enhanced the nonlinear absorption coefficient by approximately five times in comparison with non-irradiated sample. UV–visible, Raman and Fourier transform infrared spectroscopy clearly demonstrate that graphene oxide liquid crystal is not modified by laser irradiation. This work opened up the method to control and amplify the absorption properties of graphene oxide liquid crystal.

The Large and Tunable Nonlinear Absorption Response of Graphene Oxide Liquid Crystals

It is possible to change the optical properties of graphene oxide colloids by modifying their oxygen bond. We report here the use of laser irradiation and electrostatic field to change the properties of graphene oxide colloids. UV–Visible and Fourier transform infrared spectroscopes clearly demonstrate that graphene oxide is successfully modified by laser irradiation and electrostatic field. It is shown that significant enhancement in optical properties of graphene oxide colloids can be achieved by modification with the electric field and laser irradiation. Compared to the effect of the laser irradiation on the graphene oxide colloids, the result of treatment by DC electric field shows a better reduction performance and larger optical responses. In addition, it is observed that treatment of the graphene oxide colloids by electrostatic field in the presence of the 532-nm laser irradiation leads to scale down the reduction level of the sample. Results show that by using different reduction processes, we can modify the physical properties of graphene oxide for achieving tunable optical responses.

Effect of treatment by electrostatic field and 532-nm laser irradiation on optical and thermo-optical properties of graphene oxide colloids

Reactions of 3-Acylchromones with Heterocyclic Ketene Aminals: One-Pot Synthesis and Phosphatase Inhibitory Activity of Fused Pyridine Derivatives

Ab initio density functional theory calculations have been used to investigate the carbon nanotube-based P–N, N–P–N and P–N–P junctions. For this purpose, we have used a zigzag (5, 0) carbon nanotube and some of it’s derivatives, obtained by manually replacing carbon atoms with doping elements like B, N, Ge and Sn. To characterize the stability and electrical functionality of these structures, different quantum mechanical parameters such as Gibbs free energy, energy gap, dipole moment and density of states have been investigated. The obtained results indicate that the doping mechanism implemented for these structure designs, are highly promising for high speed diodes applications.

Density functional theory calculations of the carbon nanotube based P–N junction by substitution of carbon atoms with B, N, Ge and Sn

In this study we investigate the effect of atoms such as B, N, Ge and Sn on the optical and the electrical properties of capped (5, 0) zigzag carbon nanotube, using DFT calculation method. These elements were attached to the one end of the carbon nanotube. We considered four different structure designs as possible candidates for a p-n junction device. The electrical properties of these structures were investigated using the quantum chemical information analysis which leads to the energy band gap, dipole moments, electrical charges and the DOS of these structures. Further TD-DFT calculations were performed to obtain the optical properties of the structure designs to investigate the electron mobility, indicating higher conductivity and higher rectifying voltage in the CNT terminated by Sn.

http://www.ijnd.ir/article_652067_abef3ef79da85bcf490e60ec920962e6.pdf

Electrical and optical properties of a small capped (5, 0) zigzag Carbon nanotube by B, N, Ge and Sn atoms: DFT theoretical calculation

https://robots.iopscience.iop.org/article/10.1088/2053-1591/aaba54/pdf

Afshin Abbasi

Papers

Effect of treatment by electrostatic field and 532-nm laser irradiation on optical and thermo-optical properties of graphene oxide colloids

Reactions of 3-Acylchromones with Heterocyclic Ketene Aminals: One-Pot Synthesis and Phosphatase Inhibitory Activity of Fused Pyridine Derivatives

Density functional theory calculations of the carbon nanotube based P–N junction by substitution of carbon atoms with B, N, Ge and Sn

Electrical and optical properties of a small capped (5, 0) zigzag Carbon nanotube by B, N, Ge and Sn atoms: DFT theoretical calculation

Effect of B, N, Ge, Sn, K doping on electronic-transport properties of (5, 0) zigzag carbon nanotube