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Volume 4, Issue 1, (July – August 2015)

Dielectric and AC Conductivity Studies in Two Alkali Doped Boroph-osphate Glasses

Original Research Article

Journal of Chemistry and Materials Research Vol. 4 (1), 2015, 2–5

J.S. Ashwajeet, T. Sanakarappa*, R. Ramanna, and T. Sujatha


Abstract

The two alkali doped borophosphate glasses, (B2O3)0.2‒(P2O5)0.3‒(Li2O)x‒(Na2O)0.5‒x were prepared by the standard melt quenching method at 1200K. Non-crystalline nature of the samples has been confirmed by XRD studies. Dielectric studies were conducted in the temperature range from 300 to 625 K for the frequency range from 50 Hz to 1 MHz. The dielectric constant and loss were observed to be decreased with increase in frequency and that has been ascribed to the decrease in ionic contribution with increase in frequency. The high temperature electrical conductivity has been analyzed using Mott’s small polaron model and activation energies were determined. Activation energy passed through maximum and conductivity passed through minimum between 0.15 to 0.30 mole fractions of Li2O which indicates that the mixed alkali effect (MAE) occurs in these glasses and that has been discussed in terms of dynamic structure model. It is for the first time that Li2O and Na2O doped borophosphate glasses have been studied for dielectric properties and ac conductivity and MAE observed.

 

Key words: Borophosphate glasses, Density, Conductivity, Mixed alkali effect.

Received
Received in revised
Accepted
28 July 2015
13 October 2015
13 October 2015
 

Investigations on Optoelectronic Properties of New low Gap Compoun-ds Based on Carbazol and thiophene as Solar Cells Materials

Original Research Article

Journal of Chemistry and Materials Research Vol. 4 (1), 2015, 6–12

F. Agda, T. Abram, M. Taleb, L. Bejjit, M. Bouachrine,*

Abstract

In this work, we presented a theoretical study by using DFT method on four oligomeres namely TTTCbzTTT, CbzTCbzTTT, TCbzTTCbzT, TTCbzCbzTT based on calculated spin densities.Firstly we have determined the quantum chemical parameters such as the highest occupied molecular orbital energy (EHOMO), the lowest unoccupied molecular orbital energy (ELUMO) and Gap energy Voc (open circuit voltage) of the studied compounds have been calculated and discussed. The properties suggest these materials as a good candidate for organic solar cells.

 

Key words: π-Conjugated molecules; Conjugated polymers; Organic solar cells; DFT; Electronic properties.

Received

Received in revised
  Accepted
05 May 2015
-
12 October 2015
 

Development of Heat Resistant Borosilicate Glass Doped with Sodium Silico Fluoride compound

Original Research Article

Journal of Chemistry and Materials Research Vol. 4 (1), 2015, 13–18

Muhammad Saadet Khan, Phool Shahzadi*, Shahzad Alam, Khalid Javed,  Fadia Shaheen, Javed Naqvi, Akhtar Shahnaz

Abstract

The Borosilicate glass composition doped with sodium silico fluoride (Na2SiF6) which is more refined, free from seeds, bubbles and cords has been developed by using gas fired furnace without stirring system at comparatively lower temperature (1550 ͦ C )for the melting of glass instead of electric furnace which is not feasible for Pakistan due to energy crises and expenses . Many variations have been made in standard borosilicate (7740) glass composition to develop a new composition. Characterization was done by using Orton Dilatometer and ASTM Standard Methods This glass was developed first time in Pakistan at laboratory scale within our country resources and available facilities.

 

Keywords: Chemical durability, Glass, heat resistant glass, Sodium silico-fluoride, Thermal expansion coefficient.

Received
  Received in revised
Accepted
01 July 2015
15 September 2015
01 October 2015
 

The Effect of Nickel Doping on Calculation of the Optical Gap Energy and Urbach Energy in ZnO Thin Films

Original Research Article

Journal of Chemistry and Materials Research Vol. 4 (1), 2015, 19–24

Said Benramache*, Boubaker Benhaoua, Okba Belahssen

 

Abstract

Investigation of new calculate depends on the controlled optical properties of nanomaterials. Understanding the growth mechanism and growth parameters of nanostructured materials is essential. ZnO is one of the most important semiconductor materials for its semiconducting characteristics. In the present paper, we investigated a new model by theoretical methods; it is based on correlation from the experimental data’s which was used in the calculation the optical gap energy and Urbach energies. These data’s were taken from papers previously published. From obtained relations found that the experimental data and theoretical calculation are in qualitative, which were supported with the variation of solution molarities and Nickel doping. We have obtained a high correlation coefficient in the estimation of the band gap energy is higher than 0.96 with compare of Urbach energy is changed from 0.84 of undoped to Ni doped ZnO film at 0.88. The measurements by these new models have agreed with minimum relative errors, it is found in the calculations of optical band gap does not exceed 4 %, and for Urbach energy are smaller than 20 and 10 % for undoped and Nickel doped ZnO films, respectively. So that the best estimation was found at the Nickel doped ZnO thin with maximum enhancement of minimum errors were limited to 3.3 and 13 % for the band gap and the Urbach energies, respectively. The decreases in the relative errors of undoped to Nickel doped films can be explained by the fewer defects and less disorder.

 

Key words: ZnO; Thin film; Semiconductor Doping; Calculation.

   Received
Received in revised
Accepted
06 October 2015
-
21 October 2015