Mohammad Sultan Al-Assiri
Najran University
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Publication
Featured researches published by Mohammad Sultan Al-Assiri.
Journal of Molecular Graphics & Modelling | 2013
Ahmad Irfan; Abdullah G. Al-Sehemi; Mohammad Sultan Al-Assiri
We have modeled multifunctional compounds by pi-elongation and push-pull strategy from the 4,6-di(thiophen-2-yl)pyrimidine. The ground state geometries have been optimized by density functional theory while excited state geometries were optimized by time dependent density functional theory (TDDFT). Structure-property relationship, electronic, optical and charge transfer properties (ionization potential, electron affinity and reorganization energies) were computed and discussed. By TDDFT absorption and emission have been calculated. The computed parameters were compared with available experimental data. The long-range corrected functional (LC-BLYP) is overestimating the highest occupied and lowest unoccupied molecular orbital energies, energy gaps while underestimating the absorption and fluorescence wavelengths. The B3LYP is good to reproduce the experimental data. The intra-molecular charge transfer has been observed from highest occupied molecular orbitals to lowest unoccupied molecular orbitals. The strong electron withdrawing and electron donor groups efficiently reduce the energy gaps. The decrease injection barrier and smaller reorganization energies are revealing that our designed derivatives would be efficient hole as well as electron transfer materials. These derivatives would be good light emitters e.g. blue, green, orange, red and near IR. The predicted values showed that the designed derivatives would be efficient for the organic field effect transistors, photovoltaics and light emitters.
Journal of Theoretical and Computational Chemistry | 2015
Ahmad Irfan; Shabbir Muhammad; Abdullah G. Al-Sehemi; Mohammad Sultan Al-Assiri; Abul Kalam; Aijaz Rasool Chaudhry
The triphenylamine (TPA), thiophene and pyrimidine are being used as efficient advanced functional semiconductor materials. In the present study, some new TPA donor–π–acceptor derivatives were designed where TPA moiety acts as donor, thiophene-pyrimidine π-bridge and acetic/cyanoacetic acid as acceptor. The ground-state geometries were optimized at B3LYP/6-31G** level of theory. The excitation energies and oscillator strengths were computed at TD-CAM-B3LYP/6-31G** (polarizable continuum model (PCM), in methanol) level of theory. The electronic, photophysical and charge transport properties were calculated wherever possible the computed values were compared with the available experimental as well as computational data. The electron injection (ΔGinject), relative electron injection , electron coupling constants (∣VRP∣) and light harvesting efficiencies (LHE) have been calculated and compared with referenced compounds. The energies of the lowest unoccupied molecular orbitals (ELUMOs), diagonal bandgaps and energy level offsets were studied to shed light on the electron transport behavior. The effect of anchoring groups (acetic acid and cyanoacetic acid) was studied on the properties of interests in the dye and dye@Ti6O12. It was observed that after interaction of dye with the TiO2 cluster intra-molecular charge transport enhanced from HOMO of the dye to LUMO of the semiconductor cluster. The cyanoacetic acid anchoring group leads the superior LHE, ΔGinject and ∣VRP∣ which might improve the solar cell performance.
Journal of Materials Chemistry | 2015
Seung-Wook Baek; Jae-Hyoung Shim; Yun-Hyuk Ko; Jin-Seong Park; Gon-Sub Lee; Mohammed Jalalah; Mohammad Sultan Al-Assiri; Jea-Gun Park
Flexible ultra-thin silicon (∼30 μm thickness) solar cells implemented with an energy-down-shift layer showed stable flexible and twistable characteristics. In particular, spin-coating Cd0.5Zn0.5S/ZnS core/shell quantum dots (QDs) on the cells enhanced the PCE by ∼0.7% through an energy-down-shift effect that enhanced the external quantum efficiency in the UV light region. In addition, the cells demonstrated an excellent bending fatigue performance because their PCE levels were sustained at ∼12.4% after 5000 bending cycles under a strain of ∼5.72%.
Journal of Theoretical and Computational Chemistry | 2015
Shabbir Muhammad; Ahmad Irfan; Abdullah G. Al-Sehemi; Mohammad Sultan Al-Assiri; Abul Kalam; Aijaz Rasool Chaudhry
A quantum chemical investigation has been performed to spotlight the structure–property relationship among methoxybenzeylidene-based humidity sensor and water molecules. The chemical interactions among (E)-2-(4-(2-(3,4-dimethoxybenzeylidene)hydrazinyl)phenyl) ethane-1,1,2-tricarbonitrile (DMBHPET) sensor and water molecules have been studied using density functional theory (DFT) methods. The molecular structural parameters, binding energies and Infrared (IR) spectroscopic analyses have been performed to assess the nature of intermolecular interactions. Three different positions have been identified for possible attachments of H2O molecules through hydrogen bonding interactions. These positions include NH (complex 1a), p-OCH3 (complex 1b) and N=N (complex 1c) group in sensor molecule (1) for the chemical adsorption of water molecules. While, the complex 1abc includes all three sites with simultaneously three H2O molecules attached to it through hydrogen bonding. The binding energies calculated for complex 1a(NH…H2O), complex 1b(CH3O…H2O), complex 1c(N=N…H2O) and complex 1abc are -30.97, -18.41, -13.80 and -65.36 kcal/mol, respectively. The counterpoise (CP) scheme has been used to correct the basis set superposition error (BSSE) in calculation of binding energies of sensor and H2O complexes. The higher binding energy of -65.36 kcal/mol for complex 1abc represents that the present methoxybenzeylidene-based sensor has significant potential through hydrogen bonding formation for sensing humidity as indicated in our previous experimental investigation. The evidence of hydrogen bonding interactions between sensor 1 and H2O molecules has been traced through structural parameters, red shift in IR spectra as well as molecular electrostatic maps. Thus the present investigation highlights the first computational framework for a molecular level structure-binding activity of a methoxybenzeylidene-based sensor and water molecules.
Nanoscale Research Letters | 2013
Abdullah M. Asiri; Sher Bahadar Khan; Mohammed M. Rahman; Abdullah G. Al-Sehemi; S.A. Al-Sayari; Mohammad Sultan Al-Assiri
In this report, we illustrate a simple, easy, and low-temperature growth of Ag/Ag2O3/ZnO composite nanorods with high purity and crystallinity. The composite nanorods were structurally characterized by field emission scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy which confirmed that synthesized product have rod-like morphology having an average cross section of approximately 300 nm. Nanorods are made of silver, silver oxide, and zinc oxide and are optically active having absorption band at 375 nm. The composite nanorods exhibited high sensitivity (1.5823 μA.cm−2.mM−1) and lower limit of detection (0.5 μM) when applied for the recognition of phenyl hydrazine utilizing I-V technique. Thus, Ag/Ag2O3/ZnO composite nanorods can be utilized as a redox mediator for the development of highly proficient phenyl hydrazine sensor.
Journal of Fluorine Chemistry | 2014
Ahmad Irfan; Abdullah G. Al-Sehemi; Mohammad Sultan Al-Assiri
Comptes Rendus Chimie | 2015
Ahmad Irfan; Abdullah G. Al-Sehemi; Shabbir Muhammad; Aijaz Rasool Chaudhry; Mohammad Sultan Al-Assiri; Ruifa Jin; Abul Kalam; Mohd. Shkir; Abdullah M. Asiri
Computational and Theoretical Chemistry | 2014
Ahmad Irfan; Abdullah G. Al-Sehemi; Mohammad Sultan Al-Assiri
Computational and Theoretical Chemistry | 2015
Asif Mahmood; Mudassir Hussain Tahir; Ahmad Irfan; Abdullah G. Al-Sehemi; Mohammad Sultan Al-Assiri
Physica E-low-dimensional Systems & Nanostructures | 2014
Sher Bahadar Khan; Mohammed M. Rahman; Abdullah M. Asiri; Safi Asim Bin Asif; Sara Abdullah S. Al-Qarni; Abdullah G. Al-Sehemi; S.A. Al-Sayari; Mohammad Sultan Al-Assiri