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Volume 5, Issue 2, (March – April 2016)


Density Functional Theory Investigations of Optoelectronic and Photovoltaic Properties of Some Oligomers Based on Thiophene and Phenylene Substituted by Donor and Acceptor Groups

Original Research

Journal of Chemistry and Materials Research Vol. 5 (2), 2016, 25–31

S. Boussaidi, Y. Alaoui, A. Eddiouane, A. Fitri, A. Touimi Benjelloun, H. Zgou*, H. Chaib,  M. Bouachrine, M. Hamidi, T. Ben Hadda

 

Abstract

In this paper, we carried out a theoretical investigation on several conjugated oligomers based on thiophene and phenylene without and with lateral acceptor and donor substituents. The aim of this work is to study the effect of these lateral groups on the structural, optoelectronic and photovoltaic properties of all oligomers. The theoretical ground-state geometries and electronic structures of the studied molecules were obtained using the density functional theory (DFT) method at B3LYP level with 6-31G(d) basis set. The optoelectronic properties (HOMO, LUMO, Egap…) were determined from the fully optimized structures. The absorption properties (λmax, Etr, OS) of these molecules are obtained by TD-B3LYP/6-31G(d) method. The results of these investigations indicate how the photovoltaic properties can be tuned by introducing the electron-donating and electron-withdrawing groups on oligomer backbone. We suggest that these organic materials are good candidates for photovoltaic applications.

 

Keywords: Conjugated oligomers, Organic Solar cells, Thiophene, Phenylene, DFT, TD-DFT, Photovoltaic properties.

Received

Received in revised
  Accepted
14 January 2016
08 April 2016
20 April 2016
 

Potentiometric Determination of Acidity Constants of Some Pyrimidine Derivatives in Organic-Water Media

Original Research

Journal of Chemistry and Materials Research Vol. 5 (2), 2016, 32–38

Shipra Baluja*, Kajal Nandha and Paras Ramavat

 

Abstract

The acidity constants of some synthesized protonated pyrimidine derivatives were determined potentiometrically at ionic strength of 0.1 M in 1, 4-dioxane: water (50:50 v/v) system at different temperatures (298.15 to 318.15 K). Some thermodynamics parameters such as enthalpy (ΔH), Gibb’s free energy (ΔG) and entropy (ΔS) of solutions have also been evaluated at different temperatures for these systems. The thermodynamic parameters indicate that dissociation process is not spontaneous and exothermic. Thus, temperature and proton-solvent interaction play an important role in the dissociation equilibrium.

 

Keywords: Acidity constant; Pyrimidine; 1, 4-dioxane; Enthalpy; Entropy; Gibb’s energy.

Received
  Received in revised
Accepted
02 March 2016
-
28 April 2016