Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Powiadomienia systemowe

Sesja wygasła!

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Urbach energy

Sortuj według:

Ogranicz wyniki do:

Effect of reaction time on the structure and optical properties of P3HT/MWCNT-OH nanocomposites

Nurazzi, Norizan Mohd, Abdullah Norli, Ngah Demon Siti Zulaikha, Halim Norhana Abdul, Sa'aya Nurul Syahirah Nasuha, Mohamad Imran Syakir

Polimery

2022

Vol. 67, nr 5

205--211

In the present study, regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) coated hydroxylated multi-walled carbon nanotubes (MWCNT-OH) nanocomposites were prepared over different reaction times of non-covalent functionalization. The reaction time was set as 24, 48, 72, 96, and 120 hours. The structure and optical characteristics of nanocomposites were analyzed using Fourier-transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectroscopy, respectively. Reaction time affected prepared nanocomposites by decreasing the intensity of the P3HT/MWCNT-OH peaks gradually with increasing of the reaction time. Comparing with the pure P3HT and MWCNT-OH, the calculated energy band gap and the Urbach energy of the nanocomposites were reduced proportionally as the reaction time reached 120 hours and achieved 2.60 and 0.329 eV, respectively.

Syntetyzowano hydroksylowane wielościenne nanorurki węglowe (MWCNT-OH) pokryte stereoregularnym poli(3-heksylotiofen-2,5-diylu) (P3HT) oraz zbadano wpływ czasu reakcji niekowalencyjnej funkcjonalizacji na strukturę i właściwości optyczne otrzymanego nanokompozytu. Czas reakcji wynosił 24, 48, 72, 96 i 120 godzin. W badaniach wykorzystano spektroskopię w podczerwieni z transformacją Fouriera (FTIR) oraz ultrafioletową UV-Vis. Wraz ze wzrostem czasu reakcji następowało stopniowe zmniejszenie intensywności pików P3HT/MWCNT-OH. W porównaniu z P3HT i MWCNT-OH obliczona przerwa energetyczna i energia Urbacha zmniejszały się wraz z wydłużeniem czasu reakcji i osiągnęły odpowiednio 2,60 i 0,329 eV przy czasie reakcji 120 godzin.

Optical and thermal properties of TeO2–B2O3–Gd2O3 glass systems

Eevon C., Halimah M. K., Azlan M. N., El-Mallawany R., Hii S. L.

Materials Science Poland

2019

Vol. 37, No. 4

517--525

New glass samples with composition (1 – x)[(TeO₂)₇₀(B₂O₃)₃₀] – x(Gd₂O₃) with x = 0.2, 0.4, 0.6, 0.8 and 1.0 in mol% have been synthesized by conventional melt-quenching techniques. X-ray diffraction (XRD) studies were performed in order to confirm the amorphous nature of the samples. The density of the samples has been found to vary with the Gd₂O₃ content, whereas an opposite trend has been observed in the molar volume. The analysis of Fourier Transform Infrared (FT-IR) spectroscopy of the samples showed that the glass network is mainly built of TeO, TeO₄, BO₃ and BO₄ units. The addition of Gd₂O₃ changed the refractive index, optical band gap and Urbach energy of the glass samples. The thermal properties of the studied glasses were investigated by measuring the thermal diffusivity of the samples by using photoflash method at room temperature.

Optical properties of ternary tellurite glasses

Halimah M. K., Daud W. M., Sidek H. A. A., Zaidan A. W., Zainal A. S.

Materials Science Poland

2010

Vol. 28, No. 1

173--180

Test samples of ternary glass tellurite [(TeO2)65(B2O3)35]y[Ag2O]y with y = 10, 15, 20, 25, 30 mol % have been fabricated and their physical and optical properties were investigated. The optical absorption was recorded at room temperature in the wavelength range from 200 to 800 nm. From the absorption edge data, the value of the optical band gap Eopt and the Urbach energy ?E were evaluated. The value of Eopt lies between 2.15 eV and 1.85 eV for the indirect transition and for direct transition the values vary from 2.77 eV to 2.35 eV. From the experimental results, values of the optical band gap and Urbach energy were calculated. They were found to be dependent on the glass composition.