RESUMO
We have performed the ab initio calculation of the undoped and doped molecules bis (ethylenedithio) tetraselenafulvalene (BETS). Carbone (C) atoms have been substituted by Boron (B) to investigate their effects on the electronic structure and nonlinear optical, optoelectronic, and thermodynamic properties of BETS molecule. The RHF and hybrid density functional theories (WB97XD, B3PW91, and B3LYP) methods were applied, using the cc-pVDZ basis set. We found that the energy gap (Egap) of the doped molecules are respectively 2.476 eV and 2.569 eV for C8B2H8S4Se4 and C7B3H8S4Se4 with B3LYP/cc-pVDZ basis set, lower than one of the undoped molecule (3.316 eV). The significant increase values of polarizability (ËαË) and first order hyperpolarizability (ß) of the doped compounds, especially in C8B2H8S4Se4 (< α > = 4.5315 × 10-23 esu, ß = 22,672.27 × 10-33 esu and < α > = 4.518 × 10-23 esu, ß = 23,657.43 × 10-33 esu respectively for B3LYP and B3PW91) compared to those of the undoped molecule (< α > = 4.3602 × 10-23 esu, ß = 1290.38 × 10-33 esu, and < α > = 4.518 × 10-23 esu) show that the new molecules have a good nonlinear optical property. Results suggest that these molecules doped with boron are a potential candidate as semiconductors compounds and nonlinear optical materials.
RESUMO
In the present study, we theoretically determine the optoelectronic, electronic, nonlinear optical (NLO) and thermodynamic properties of new materials from the conjugated organic polymer poly (3,4-ethylenedioxythiophene) (PEDOT) doped with halogens (fluorine and chlorine), combined with the organic semiconductor 4-[2-(2-N, N-dihydroxy amino thiophene) vinyl] benzenamine (DATVB). The molecular geometry of the ground state, the optoelectronics and electronic parameters have been calculated by combining the 6-311++G (d, p) basis set with various functionals of the density functional theory (DFT). The functionals B3LYP and CAM-B3LYP have been used for NLO parameters. The energy gaps obtained for all the compounds are less than 3.0 eV. These results clearly show that PEDOT and its derivatives can be considered as good semiconductors. They can be tested for use in the manufacture of organic solar cells (OSC) and organic light-emitting diodes (OLED). The first order hyperpolarizabilities of these PEDOT hybrid compounds are much higher than those of the reference compound for NLO applications, namely para-nitroaniline (p-NA), which opens up a new field of application for PEDOT in NLO devices. The thermodynamic parameters such as the zero-point vibrational energy (ZPVE), the enthalpy (H), the heat capacity at constant volume (cv), the entropy (S) and the free energy (G) have been calculated and are reported herein.
RESUMO
DFT calculations were performed to study the nanostructures obtained by the multifunctionalization of one and two acetylsalicylic acid radicals on fullerene ylide. The increase in the number of aspirin molecules functionalized on fullerene ylide increases the stability of the formed nanostructures. The analysis of the vibrational spectra of these nanostructures shows that the formed systems are stable and present some vibrational modes in accordance with the experimental data. The degree of solubility and polarity of these nanostructures increases with the number of functionalized molecules. Multifunctionalization considerably improves the nonlinear optical properties of the modeled nanostructures. With functionalization of isolated aspirin molecule, the electronic properties are very improved, not too much passing to multifunctionalization. The formed nanostructures are soft, more electrophilic, and more reactive than the aspirin molecule, but with multifunctionalization the charge transfer decreases.
