A study of the optical band gap energy and Urbach energy of fullerene (C60) doped PMMA nanocomposites

Improving the optical response of tellurite glasses via controlled doping of rare earth is the key issue in lasing materials. A series of glasses of the form (74.4-x)TeO2(4.3)Li2O(21.3)LiCl (x)Eu2O3 with 0.0 x 2.0 mol% are synthesized using melt-quenching technique and the influence of Eu2O3 content on their UV-Vis absorption properties are examined. The absorption spectra reveal two prominent peaks centered at 464 and 533 nm corresponding to 7F05D2 and 7F15D1 transitions, respectively. The optical band gap energy for direct and indirect transitions are found to be in the range of 3.294-3.173 eV and 3.067-2.971 eV, respectively. The decrease optical band gap energy with the increase of Eu2O3 contents is attributed to the generation of non-bridging oxygen (NBOs). The increase in Urbach energy from 0.226-0.308 eV with the increase of Eu2O3 contents signifies the variation in disorder and compactness of the glass network.

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Effect of Stepwise Replacement of LiF by Bi2O3 and of Annealing on Optical Properties of LiF⋅B2O3 Glasses

ISRN Optics ◽

10.5402/2012/193185 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Susheel Arora ◽

Virender Kundu ◽

D. R. Goyal ◽

A. S. Maan

Keyword(s):

Optical Properties ◽

Band Gap ◽

Optical Band Gap ◽

Urbach Energy ◽

Optical Characterization ◽

Band Gap Energy ◽

Gap Energy ◽

Different Temperatures ◽

Quench Method

Bismuth fluoroborate glasses with compositions xBi2O3⋅(40-x)LiF⋅60 B2O3 (x=0,5,10,15, and 20) are synthesized by melt-quench method. Optical characterization was carried out to examine variation of optical band gap energy (Eg) and Urbach energy (EU) with respect to the concentration. It reflects the effect of stepwise replacement of non-oxide and less polarizable LiF by an oxide and more polarizable (Bi2O3) group on the optical properties of the samples. The value of Eg decreases with increase in concentration of Bi2O3. The samples were subjected to annealing at different temperatures (300°C, 350°C, and 400°C), and the effect of annealing on the optical properties of various samples was again studied. Annealing affects remarkably the values of Eg and EU in the samples with x=0.

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Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v7i3.1581 ◽

2015 ◽

Vol 7 (3) ◽

pp. 1923-1930

Author(s):

Austine Amukayia Mulama ◽

Julius Mwakondo Mwabora ◽

Andrew Odhiambo Oduor ◽

Cosmas Mulwa Muiva ◽

Boniface Muthoka ◽

...

Keyword(s):

Thin Films ◽

Band Gap ◽

Optical Band Gap ◽

Thermal Evaporation ◽

Optical Transition ◽

Bulk Material ◽

Band Gap Energy ◽

Optical Absorbance ◽

Gap Energy ◽

Constituent Elements

Â Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 â‰¤ x â‰¤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the systemâ€™s network.

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Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

Materials ◽

10.3390/ma14051118 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1118

Author(s):

Ibrahim Mustapha Alibe ◽

Khamirul Amin Matori ◽

Mohd Hafiz Mohd Zaid ◽

Salisu Nasir ◽

Ali Mustapha Alibe ◽

...

Keyword(s):

Solid State ◽

Thermal Treatment ◽

Band Gap ◽

Optical Band Gap ◽

Dopant Concentration ◽

Blue Emission ◽

Green Emission ◽

Band Gap Energy ◽

Solid State Lighting ◽

Gap Energy

The contemporary market needs for enhanced solid–state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid–state lighting applications.

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Characterization, Thermal Effect on Optical Band Gap Energy and Photoluminescence in Wurtzite ZnO:Er Nanocrystallites

Materials Today Proceedings ◽

10.1016/j.matpr.2016.01.046 ◽

2016 ◽

Vol 3 (2) ◽

pp. 145-151 ◽

Cited By ~ 4

Author(s):

Anitha ◽

Usha ◽

Jithin ◽

Christy ◽

Varughese

Keyword(s):

Band Gap ◽

Thermal Effect ◽

Optical Band Gap ◽

Band Gap Energy ◽

Gap Energy

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The Optical Performance of Holmium Oxide Doped Tellurite Glass for Potential Optical Fiber

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.317.95 ◽

2021 ◽

Vol 317 ◽

pp. 95-99

Author(s):

Muhammad Noorazlan Abd Azis ◽

Halimah Mohamed Kamari ◽

Suriani Abu Bakar ◽

Azlina Yahya ◽

Umar Saad Aliyu

Keyword(s):

Refractive Index ◽

Band Gap ◽

Tellurite Glass ◽

Optical Band Gap ◽

Band Gap Energy ◽

X Ray Diffraction ◽

Xrd Pattern ◽

Gap Energy ◽

Xrd Method ◽

Nonlinear Pattern

Borotellurite glass had been widely applied in the field of optical communications and devices. In this work, holmium oxides doped borotellurite glass had been successfully fabricated via conventional melt-quenched technique. The structural properties of holmium doped tellurite glass were found using x-ray diffraction (XRD) method. The nonexistence of sharp peaks in XRD pattern shows that the inclusion of holmium tellurite glass leads to the formation long range of disorderness. The optical properties of the glass system such as refractive index and optical band gap energy are investigated using UV-Vis spectrophotometer. The value of refractive index is found in nonlinear trend along with holmium oxides concentration. It is found that the refractive index is more than 2 at 0.01, 0.03 and 0.04 of holmium concentrations. The optical band gap energy was found in similar trend with refractive index which is in nonlinear pattern.

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Effect of thickness on the optical properties of Gaas thin films

Journal of Bangladesh Academy of Sciences ◽

10.3329/jbas.v37i1.15684 ◽

2013 ◽

Vol 37 (1) ◽

pp. 83-91 ◽

Cited By ~ 13

Author(s):

Chitra Das ◽

Jahanara Begum ◽

Tahmina Begum ◽

Shamima Choudhury

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Refractive Index ◽

Band Gap ◽

Optical Band Gap ◽

Visible Region ◽

Solar Spectrum ◽

Band Gap Energy ◽

Optical Parameters ◽

Gap Energy

Effect of thickness on the optical and electrical properties of gallium arsenide (GaAs) thin films were studied. The films of different thicknesses were prepared by vacuum evaporation method (~10-4 Pa) on glass substrates at a substrate temperature of 323 K. The film thickness was measured in situ by a frequency shift of quartz crystal. The thicknesses were 250, 300 and 500 nm. Absorption spectrum of this thin film had been recorded using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300 - 2500 nm. The values of some important optical parameters of the studied films (absorption coefficient, optical band gap energy and refractive index; extinction co-efficient and real and imaginary parts of dielectric constant) were determined using these spectra. Transmittance peak was observed in the visible region of the solar spectrum. Here transmittance showed better result when thicknesses were being increased. The optical band gap energy was decreased by the increase of thickness. The refractive index increased by increasing thickness while extinction co-efficient and real and imaginary part of dielectric constant decreased. DOI: http://dx.doi.org/10.3329/jbas.v37i1.15684 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 1, 83-91, 2013

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