Super alkali (OLi3) doped boron nitride with enhanced nonlinear optical behavior

Author(s):  
Ali Raza Ayub ◽  
Rao Aqil Shehzad ◽  
Saleh S. Alarfaji ◽  
Javed Iqbal

In this study, density functional theory is used to examine the electronic and nonlinear optical properties of a narrative class boron nitride (B[Formula: see text]N[Formula: see text]) doped with super alkali OLi3. From the computational investigations, these complexes are highly stable and superalkali prefer a cubic position of the nanocage energetically to be chemisorbed. When superalkali doped on B[Formula: see text]N[Formula: see text], a significant decrease in the HOMO–LUMO energy gap was observed and this shifted the B[Formula: see text]N[Formula: see text] nanocage from insulator to n-type semiconductor. The HOMO–LUMO energy gap of pure B[Formula: see text]N[Formula: see text] was 6.84[Formula: see text]eV and when superalkali (OLi3) is doped on it, the HOMO–LUMO energy gap was changed in the range of 3.94–0.42[Formula: see text]eV. BNM2b showed a HOMO–LUMO energy gap of 3.94[Formula: see text]eV, while BNM4a showed a minimum HOMO–LUMO energy gap (0.42[Formula: see text]eV). Further, these systems showed a remarkable large first hyperpolarizability ([Formula: see text]) in the range of 626.72–75,757[Formula: see text]au and 1045–12,6261[Formula: see text]au. When the charge was shifted from superalkali to the nanocage, a small change in transition energies has occurred and consequently, hyperpolarizability ([Formula: see text]) values increased significantly. The vertical ionization energy of pure B[Formula: see text]N[Formula: see text] is 7.71[Formula: see text]eV, as superalkali is doped on it showed a significant change in VIE in BNM2b that indicated the highest VIE of about 6.47[Formula: see text]eV and BNM4a indicated lowest VIE 2.51[Formula: see text]eV. The TD-DFT investigations described that complexes illustrated greater transparency in the UV part which involves apart from greater NLO response for practical applications in the area of activity of optoelectronics.

2006 ◽  
Vol 05 (03) ◽  
pp. 595-608 ◽  
Author(s):  
KRIENGSAK SRIWICHITKAMOL ◽  
SONGWUT SURAMITR ◽  
POTJAMAN POOLMEE ◽  
SUPA HANNONGBUA

The structural and energetic properties of polyfluorene and its derivatives were investigated, using quantum chemical calculations. Conformational analysis of bifluorene was performed by using ab initio (HF/6-31G* and MP2/6-31G*) and density functional theory (B3LYP/6-31G*) calculations. The results showed that the local energy minimum of bifluorene lies between the coplanar and perpendicular conformation, and the B3LYP/6-31G* calculations led to the overestimation of the stability of the planar pi systems. The HOMO-LUMO energy differences of fluorene oligomers and its derivatives — 9,9-dihexylfluorene (DHPF), 9,9-dioctylfluorene (PFO), and bis(2-ethylhexyl)fluorene (BEHPF) — were calculated at the B3LYP/6-31G* level. Energy gaps and effective conjugation lengths of the corresponding polymers were obtained by extrapolating HOMO-LUMO energy differences and the lowest excitation energies to infinite chain length. The lowest excitation energies and the maximum absorption wavelength of polyfluorene were also performed, employing the time-dependent density functional theory (TDDFT) and ZINDO methods. The extrapolations, based on TDDFT and ZINDO calculations, agree well with experimental results. These theoretical methods can be useful for the design of new polymeric structures with a reducing energy gap.


2021 ◽  
Vol 4 (4) ◽  
pp. 236-251
Author(s):  
A. S. Gidado ◽  
L. S. Taura ◽  
A. Musa

Pyrene (C16H10) is an organic semiconductor which has wide applications in the field of organic electronics suitable for the development of organic light emitting diodes (OLED) and organic photovoltaic cells (OPV). In this work, Density Functional Theory (DFT) using Becke’s three and Lee Yang Parr (B3LYP) functional with basis set 6-311++G(d, p) implemented in Gaussian 03 package was  used to compute total energy, bond parameters, HOMO-LUMO energy gap, electron affinity, ionization potential, chemical reactivity descriptors, dipole moment, isotropic polarizability (α), anisotropy of polarizability ( Δ∝) total first order hyper-polarizability () and second order hyperpolarizability (). The molecules used are pyrene, 1-chloropyrene and 4-chloropyrene  in gas phase and in five different solvents: benzene, chloroform, acetone, DMSO and water. The results obtained show that solvents and chlorination actually influenced the properties of the molecules. The isolated pyrene in acetone has the largest value of HOMO-LUMO energy gap of and is a bit closer to a previously reported experimental value of  and hence is the most stable. Thus, the pyrene molecule has more kinetic stability and can be described as low reactive molecule. The calculated dipole moments are in the order of 4-chloropyrene (1.7645 D) < 1-chloropyrene (1.9663 D) in gas phase. The anisotropy of polarizability ( for pyrene and its derivatives were found to increase with increasing polarity of the solvents.  In a nutshell, the molecules will be promising for organic optoelectronic devices based on their computed properties as reported by this work.


2015 ◽  
Vol 68 (9) ◽  
pp. 1438 ◽  
Author(s):  
Zahra Azizi ◽  
Mehdi Ghambarian ◽  
Mohammad A. Rezaei ◽  
Mohammad Ghashghaee

Various saturated five-membered N,X-heterocyclic carbenes (X = N, O, S, P, Si, C, and B) have been studied by ab initio and density functional theory (DFT) methods. The substitutions alter the properties of the reference carbene from the viewpoint of electronic structure, stability, nucleophilicity, and basicity. Our study shows that the oxygen containing carbene (X = O) induces the highest HOMO–LUMO energy gap (ΔEHOMO–LUMO), while carbene with X = N has the widest singlet–triplet energy difference (ΔEs–t). The nucleophilicity of the carbene derivatives increased upon replacement of C, Si, and B, with the effect of the boron substituent being more pronounced. In addition, the basicity of the structure increased for the carbene derivatives with X = C and B with the latter substitution imposing a remarkably higher effect. Moreover, the substitution of boron at the α-position of the carbene increased the nucleophilicity and basicity, while inducing a reduction in the values of ΔEs–t and ΔEHOMO–LUMO.


Author(s):  
Gamal Al Ati ◽  
Karim Chkirate ◽  
Joel T. Mague ◽  
Nadeem Abad ◽  
Redouane Achour ◽  
...  

The title molecule, C13H16N4O, adopts an angular conformation. In the crystal a layer structure is generated by N—H...O and N—H...N hydrogen bonds together with C—H...π(ring) interactions. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H...H (53.8%), H...C/C...H (21.7%), H...N/N...H (13.6%), and H...O/O...H (10.8%) interactions. The optimized structure calculated using density functional theory (DFT) at the B3LYP/ 6–311 G(d,p) level is compared with the experimentally determined structure in the solid state. The calculated HOMO–LUMO energy gap is 5.0452 eV.


2019 ◽  
Vol 10 (1) ◽  
pp. 4734-4739

Molecular and bimolecular properties are important factors to judge the functionality of polymer/biopolymer composites. Accordingly, molecular modeling is conducted to study the electronic properties of Polyvinyl Alcohol (PVA); Sodium Alginate (SA) as well as their composites. Accordingly, Density functional theory (DFT) at B3LYB level using 6-311/G (d, p) basis set is utilized to study the model structures. Total dipole moment (TDM), HOMO/LUMO energy gap, electrostatic potential (ESP) are calculated at B3LYB level for all studied structures. The results of TDM, HOMO/LUMO energy gap and ESP indicated that the TDM increased, HOMO/LUMO energy gap decreased and electro-negativity increased for the structures under study. Thermal parameters at PM6 are calculated including final heat of formation; free energy; entropy; enthalpy and heat capacity as a function of temperature. Thermal parameters show a variation with changing the site of interaction which indicated that the coordination of PVA/SA is an important factor for describing PVA/SA composite.


2019 ◽  
Vol 75 (11) ◽  
pp. 1582-1585 ◽  
Author(s):  
Adnan M. Qadir ◽  
Sevgi Kansiz ◽  
Necmi Dege ◽  
Georgina M. Rosair ◽  
Igor O. Fritsky

In the title compound, bis(2-methoxyethyl xanthato-κS)(N,N,N′,N′-tetramethylethylenediamine-κ2 N,N′)zinc(II) acetone hemisolvate, [Zn(C4H7O2S2)2(C6H16N2)]·0.5C3H6O, the ZnII ion is coordinated by two N atoms of the N,N,N′,N′-tetramethylethylenediamine ligand and two S atoms from two 2-methoxyethyl xanthate ligands. The amine ligand is disordered over two orientations and was modelled with refined occupancies of 0.538 (6) and 0.462 (6). The molecular structure features two C—H...O and two C—H...S intramolecular interactions. In the crystal, molecules are linked by weak C—H...O and C—H...S hydrogen bonds, forming a three-dimensional supramolecular architecture. The molecular structure was optimized using density functional theory (DFT) at the B3LYP/6–311 G(d,p) level. The smallest HOMO–LUMO energy gap (3.19 eV) indicates the suitability of this crystal for optoelectronic applications. The molecular electrostatic potential (MEP) further identifies the positive, negative and neutral electrostatic potential regions of the molecules. Half a molecule of disordered acetone was removed with the solvent-mask procedure in OLEX2 [Dolomanov et al. (2009). J. Appl. Cryst. 42, 339–341] and this contribition is included in the formula.


2021 ◽  
Author(s):  
Muhammad Ishaq ◽  
Rao Aqil Shehzad ◽  
Khurshid Ayub ◽  
javed iqbal

Abstract The concern of the present study is to investigate the non-linear optical properties of super halogen doped borophene owing to its broad applications. The first principle study of the material for its non-linear optical properties elaborated its use for electrical and optical applications. The super halogen-based borophene in lithium ion-based batteries and medical appliances have made it one of the most potential materials for optoelectronics. First, hyperpolarizability (βo) of pure and doped B36 is computed and the difference between their values was examined. The vertical ionization energy (VIE) was calculated for pure and doped systems. The interaction energy (Eint) for all combinations was computed. It would be expected to one of the best materials to have high capacity and resistance. For all the calculations and to calculate the HOMO and LUMO energy gap, the density functional theory (DFT) method was used. After observing all the above properties, it was predicted that these combinations are more beneficial and displayed the better nonlinear optical (NLO) for electronic devices.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Prabhat Ranjan ◽  
Praveen K. Surolia ◽  
Tanmoy Chakraborty

Abstract Iron-based chalcopyrite materials have diverse applications in solar cells, spintronic, thermoelectric devices, LEDs and medical sciences. In this report we have studied structure, electronic and optical properties of chalcopyrite-type nano-cluster XFeY2 (X=Cu, Ag, Au; Y=S, Se, Te) systematically by using Density Functional Theory (DFT). Our computed HOMO-LUMO energy gap of XFeY2 is in the range of 1.568–3.982 eV, which endorses its potential application in optoelectronic devices and solar cells. The result shows that chalcopyrite-type material AuFeS2 having a star-type structure with point group C2v and sextet spin multiplicity, is the most stable cluster with HOMO-LUMO energy gap of 3.982 eV. The optical properties viz. optical electronegativity, refractive index, dielectric constant, IR and Raman activity of these nano-clusters are also investigated. The result exhibits that HOMO-LUMO energy gap of XFeY2 along with optical electronegativity and vibrational frequency decreases from S to Se to Te, whereas refractive index and dielectric constant increases in the reverse order.


Fourier Transfer infrared and Raman spectra in the range of 4000-400 cm-1 and 3500-50 cm-1 were recorded to study the vibrational spectra of 5-chloro-2-hydroxyacetophenone (CHAP). Using density functional theory (DFT/B3LYP) with 6-31+G(d,p) and 6-311++G(d,p) basis sets the various geometrical parameters such as Raman activities, infrared intensities and optimum frequencies were calculated. The HOMO-LUMO energy gap has been computed which confirms the charge transfer of the molecular system. Mulliken’s atomic charges associated with each atom and thermodynamic parameters have also been reported with the same level of DFT.


2014 ◽  
Vol 68 (3) ◽  
Author(s):  
Ali Peyghan ◽  
Maziar Noei

AbstractThe functionalisation of C60 fullerene with 2,3-dimethylene-1,4-dioxane (I) and 2,5-dioxabicyclo [4.2.0]octa-1(8),6-diene (II) was investigated by the use of density functional theory calculations in terms of its energetic, structural, field emission, and electronic properties. The functionalisation of C60 with I was previously reported experimentally. The I and II molecules are preferentially attached to a C—C bond shared and located between two hexagons of C60 via [4+2] and [2+2] cycloadditions bearing reaction energies of −15.9 kcal mol−1 and −72.4 kcal mol−1, respectively. The HOMO-LUMO energy gap and work function of C60 are significantly reduced following completion of the reactions. The field electron emission current of the C60 surface will increase after functionalisation of either the I or II molecule.


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