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Number of results: 4
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Abstract

Five new derivatives of 4,6-di(thiophen-2-yl)pyrimidine (DTP) were designed by structural modification with the aim to tune the electro-optical and charge transfer properties. The effect of oligocene and oligocenothiophene incorporation/substitution was investigated on various properties of interests. The smaller hole reorganization energy revealed that compounds 1-5 might be good hole transfer contenders. The smaller hole reorganization energy of newly designed five DTP derivatives than the pentacene showed that prior compounds might be good/comparable hole transfer materials than/to that of pentacene. The computed electron reorganization energy of DTP derivatives 1-5 are 124, 185, 93, 95 and 189 meV smaller than the meridional-tris (8-hydroxyquinoline) aluminum (mer-Alq3) illuminating that electron mobility of these derivatives might be better/comparable than/to referenced compound.

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Authors and Affiliations

A. Irfan
A.R. Chaudhry
A.G. Al-Sehemi
S. Muhammad
R. Jin
S. Tang
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Abstract

Structural and optical properties of graphene with a vacancy and B, N, O and F doped graphene have been investigated computationally using density functional theory (DFT). We find that B is a p-type while N, O and F doped graphene layers, as well as graphene with a vacancy are n-type semiconductors. Optical properties for both cases of in plane (E ⊥ c) and out of plane (E || c) polarization of light are investigated. It is observed that with the increase in the number of electrons entering the supercell, the amount of absorption of the system decreases and the absorption peaks are transferred to higher energies (blue shift).

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Authors and Affiliations

M. Goudarzi
S.S. Parhizgar
J. Beheshtian
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Abstract

The electronic, optical and thermoelectric properties of zirconia-based MgZrO3 oxide have been studied theoretically at a variant pressure up to 25 GPa. Calculations for the formation energy and tolerance factor reveal the thermodynamic and structural stability of MgZrO3. To tune the indirect band gap from to a direct band gap, the optimized structure of MgZrO3 has been subjected to external pressure up to 25 GPa. The optical properties have been discussed in the form of dielectric constant and refraction that brief us about the dispersion, polarization, absorption, and transparency of the MgZrO3. In the end, the thermoelectric parameters have been analyzed at variant pressure against the chemical potential and temperature. The narrow band gap and high absorption in the ultraviolet region increase the demand of the studied oxide for energy harvesting device applications.

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Authors and Affiliations

N.A. Noor
M. Rashid
Q. Mahmood
B. Ul Haq
M.A. Naeem
A. Laref
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Abstract

The perovskites XBiO3 (X = Al, Ga, In) have been studied in terms of mechanical, optical and thermoelectric behavior for energy harvesting application. Density functional theory is applied to study electronic, optical and thermoelectric properties of the studied materials. Structural, mechanical and thermodynamic stabilities are confirmed from the tolerance factor, Born mechanical stability and formation energy/specific heat capacity. Poisson and Plough ratios show the studied materials are ductile and have ability to withstand pressure. Band structure analysis shows the indirect band gap 3.0/2.1/1.0 eV for ABO/GBO/IBO. A complete set of optical spectra is reported by dielectric constants, refractive index, optical conduction, absorption of light and optical loss energy. Shifting of maximum absorption band to visible region increases the potential of perovskites XBiO3. Transport characteristics are also investigated by electrical conductivity, Seebeck coefficient and figure of merit.

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Authors and Affiliations

Q. Mahmood
S. A. Rouf
E. Algrafy
G. Murtaza
S. M. Ramay
A. Mahmood

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