College of Science, Chemistry Department
Professor, Ph.D. in Chemistry Science
Associate Dean for Scientific Affairs/ College of Science/ Al-Nahrain University
Professor, Ph.D. in Chemistry Science
Organic Chemistry, liquid crystal synthesis
Aqel M. Rasol and Nasreen R. Jber AIP Publishing
Zinah Hussein Ali, Nasreen R. Jber, and Abbas Khudhair Abbas AIP Publishing
Zinah H. Ali and Nasreen R. Jber AIP Publishing
Zainab Jasim and Nasreen R. Jber AIP Publishing
Lamees A. Abdullah, Farah G. Khalid, Rawa K. Ibrahim, Aseel I. Mahmood, Alaa A. Rashad, and Nisreen R. Jber Springer Science and Business Media LLC
Lamees A. Abdullah, Farah G. Khalid, Alaa A. Rashad, and Nasreen R. Jber AIP Publishing
This study reported the photoluminescence (PL) of nematic liquid crystal (LC) doped with gold nanoparticles (AuNPs). Our results demonstrated PL emission intensity of MBBA LC is improved with doping AuNPs, and the improvement of PL intensity increased with elevating concentration of AuNPs. As well as, the emission peak is changed due to presence of AuNPs. It was showed PL emission peak of LC has been shifted towards longer wavelength by 78nm in presence of 0.1 AuNPs. A small amount of AuNPs can be improved the PL intensity.This study reported the photoluminescence (PL) of nematic liquid crystal (LC) doped with gold nanoparticles (AuNPs). Our results demonstrated PL emission intensity of MBBA LC is improved with doping AuNPs, and the improvement of PL intensity increased with elevating concentration of AuNPs. As well as, the emission peak is changed due to presence of AuNPs. It was showed PL emission peak of LC has been shifted towards longer wavelength by 78nm in presence of 0.1 AuNPs. A small amount of AuNPs can be improved the PL intensity.
Lamees A. Abdullaha, Alaa Adnan Rashad, Nasreen Raheem Jber, Aseel Ibrahim Mahmood, and Rawa Khalil Ibrahim Southwest Jiaotong University
Gold nanoparticles (AuNPs) have been prepared for doping liquid crystal (LC) with different concentrations to study linear and nonlinear optical properties utilizing UV spectrum and Z scan technique, respectively. Z scan methods are performed by He-Ne laser at 632.8 Nanometer wavelength. It is observed that the samples can absorb in the UVA range (280-400 nm). Pure LC has high absorbance and the peak of absorbance decreases when the concentration of AuNPS increases due to the AuNPs. The nonlinear optical (NLO) properties of LC were improved by increasing the concentration of AuNPs. The presence of AuNPs changed the behavior of pure LC from two-photon absorption (TPA) to saturable absorption.
Alaa Adnan Rashad, Nasreen Raheem Jber, and Mehdi Salih Shihab Elsevier BV
Linh I Awad and Nasreen R Jber Dr. Yashwant Research Labs Pvt. Ltd.
In this study, new compounds of discotic liquid crystalline dendrimers are prepared which is derived from 1,3,5-triphenylbenzene. The synthesis of these compounds shows the effect of dendrimer unit on the mesogenic properties. The structures of prepared compounds characterized by using spectroscopic method e.g. FT-IR and 1HNMR. The liquid crystalline phases of prepared compounds was identified by using the hot-stage polarizing optical microscope (POM) and differential scanning calorimeter (DSC).
Nasreen R. Jber, Nisreen H. Karam, and Ammar H. Al-Dujaili Informa UK Limited
Abstract The design, synthesis, and characterization of a star shaped 2,4,6-tris-(4`-carboxyphenoxy)-1,3,5-triazine liquid crystalline with columnar discotic mesophase properties establish H-bond interactions with 3,5-dialkoxypyidine were reported. The structures of the synthesized compounds were actually determined by elementary analysis, and FT-IR, 1HNMR, 13CNMR, and mass spectroscopy. The mesomorphic properties of these mesogens were examined using differential scanning calorimetry (DSC) and optical polarizing microscopy (OPM). The synthesized molecules exhibited enantiotropic hexagonal columnar liquid crystal, which depends for the H- bond complex in a 1:3 ratio.
Nisreen H. Karam, Nasreen R. Jber, and Ammar H. Al-Dujaili Informa UK Limited
Abstract The synthesis, characterization and mesomorphic properties of two new series of triazine-core based liquid crystals have been investigated. The amino triazine derivatives were characterized by elemental analysis, Fourier transforms infrared (FTIR), 1HNMR and mass spectroscopy. The liquid crystalline properties of these compounds were examined by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). DSC and POM confirmed nematic (N) and columnar mesophase textures of the materials. The formation of mesomorphic properties was found to be dependent on the number of methylene unit in alkoxy side chains.
Shereen M. Faraj, Shaimaa M. Abd Al-Baqi, Nasreen R. Jber, and Johnny Fisher ASME International
Porous silicon (PS) has become the focus of attention in upgrading silicon for optoelectronics. In this work, various structures were produced depending on the formation parameters by photo-electrochemical etching (PECE) process of n- and p-type silicon wafer at different time durations (5–90 mins) and different current densities (5, 15, and 20 mA/cm2) for each set of time durations. Diode lasers of 405 nm, 473 nm, and 532 nm wavelengths, each 50 mW power, were used to illuminate the surface of the samples during the etching process. The results showed that controlled porous layers were achieved by using blue laser, giving uniform structure which can make it possible to dispense with expensive methods of patterning the silicon.
Nasreen Raheem Jber, Alaa Adnan Rashad, and Mehdi Salih Shihab Elsevier BV
Abstract In this work, the nematic liquid crystal (LC) N-(4′-methoxybenzylidene)-4-n-butylaniline (MBBA) was prepared and doped with different concentrations (0.025, 0.05, 0.06, 0.07, 0.08, and 0.1 wt.%) of multi-walled carbon nanotubes (CNTs) at room temperature to study the electric properties of (LC–CNTs) cell. The experimental results showed that capacitance of (LC–CNTs) cell became higher than that of pure LC cell. The dielectric permittivity is determined as a function of applied frequency (100 Hz to 100 kHz) at voltage (5 V); it is found that increasing concentration of CNTs (0.1 wt.%) led to increase in the real part dielectric constant and decrease in imaginary part for (LC–CNTs) cell compared with the pure liquid crystal. Also conductivity of (LC–CNTs) cell was increased with increasing concentration of CNTs more than 0.05 wt.%. Theoretical study was carried out by using PM3 method for stable geometries of a nematic liquid crystal molecule of MBBA assembled parallel on a molecule of single-walled carbon nanotube (CNT). The result showed that the interaction caused by π,π-stacking between MBBA molecule and the wall of CNT and that may lead to formation of the local short range orientation order by LC molecules on the surface of the CNT. The binding energy of the LC molecule on the CNT wall was within the typical van der Waals interaction.