Strain Effects on the Band Gap and Diameter of CdSe Core and CdSe/ZnS Core/Shell Quantum Dots at Any Temperature
We present the results of an experimental study about strain effects on the core band gap and diameter of spherical bare CdSe core and CdSe/ZnS core/shell quantum dots (QDs) synthesized by using a colloidal technique at varying temperatures. Structural characterizations were made by using X-ray diff...
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| Format: | Article |
| Language: | English |
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Wiley
2019-01-01
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| Series: | Advances in Materials Science and Engineering |
| Online Access: | http://dx.doi.org/10.1155/2019/3764395 |
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| author | Md. Rezaul Karim Mesut Balaban Hilmi Ünlü |
| author_facet | Md. Rezaul Karim Mesut Balaban Hilmi Ünlü |
| author_sort | Md. Rezaul Karim |
| collection | DOAJ |
| description | We present the results of an experimental study about strain effects on the core band gap and diameter of spherical bare CdSe core and CdSe/ZnS core/shell quantum dots (QDs) synthesized by using a colloidal technique at varying temperatures. Structural characterizations were made by using X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) techniques. Optical characterizations were made by using UV-Vis absorption and fluorescence emission spectroscopies. The XRD analysis suggests that the synthesized bare CdSe core and CdSe/ZnS core/shell QDs have zinc blende crystal structure. HRTEM results indicate that the CdSe core and CdSe/ZnS QDs have average particle sizes about 3.50 nm and 4.84 nm, respectively. Furthermore, compressive strain causes an increase (decrease) in the core band gap (diameter) of spherical CdSe/ZnS core/shell QDs at any temperature. An elastic strain-modified effective mass approximation (EMA) predicts that there is a parabolic decrease (increase) in the core band gap (diameter) of QDs with temperature. The diameter of spherical bare CdSe core and CdSe/ZnS core/shell QDs calculated by using the strain-modified EMA, with core band gap extracted from absorption spectra, are in excellent agreement with the HRTEM data. |
| format | Article |
| id | doaj-art-7337dcaef0cc4b94b3a892ae595c2fd7 |
| institution | Kabale University |
| issn | 1687-8434 1687-8442 |
| language | English |
| publishDate | 2019-01-01 |
| publisher | Wiley |
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| series | Advances in Materials Science and Engineering |
| spelling | doaj-art-7337dcaef0cc4b94b3a892ae595c2fd72025-02-03T07:24:38ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422019-01-01201910.1155/2019/37643953764395Strain Effects on the Band Gap and Diameter of CdSe Core and CdSe/ZnS Core/Shell Quantum Dots at Any TemperatureMd. Rezaul Karim0Mesut Balaban1Hilmi Ünlü2İstanbul Technical University, Faculty of Science and Letters, Department of Physics Engineering, 34485 Maslak, İstanbul, TurkeyYıldız Technical University, Faculty of Science, Department of Physics, 34220 Esenler, İstanbul, Turkeyİstanbul Technical University, Faculty of Science and Letters, Department of Physics Engineering, 34485 Maslak, İstanbul, TurkeyWe present the results of an experimental study about strain effects on the core band gap and diameter of spherical bare CdSe core and CdSe/ZnS core/shell quantum dots (QDs) synthesized by using a colloidal technique at varying temperatures. Structural characterizations were made by using X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) techniques. Optical characterizations were made by using UV-Vis absorption and fluorescence emission spectroscopies. The XRD analysis suggests that the synthesized bare CdSe core and CdSe/ZnS core/shell QDs have zinc blende crystal structure. HRTEM results indicate that the CdSe core and CdSe/ZnS QDs have average particle sizes about 3.50 nm and 4.84 nm, respectively. Furthermore, compressive strain causes an increase (decrease) in the core band gap (diameter) of spherical CdSe/ZnS core/shell QDs at any temperature. An elastic strain-modified effective mass approximation (EMA) predicts that there is a parabolic decrease (increase) in the core band gap (diameter) of QDs with temperature. The diameter of spherical bare CdSe core and CdSe/ZnS core/shell QDs calculated by using the strain-modified EMA, with core band gap extracted from absorption spectra, are in excellent agreement with the HRTEM data.http://dx.doi.org/10.1155/2019/3764395 |
| spellingShingle | Md. Rezaul Karim Mesut Balaban Hilmi Ünlü Strain Effects on the Band Gap and Diameter of CdSe Core and CdSe/ZnS Core/Shell Quantum Dots at Any Temperature Advances in Materials Science and Engineering |
| title | Strain Effects on the Band Gap and Diameter of CdSe Core and CdSe/ZnS Core/Shell Quantum Dots at Any Temperature |
| title_full | Strain Effects on the Band Gap and Diameter of CdSe Core and CdSe/ZnS Core/Shell Quantum Dots at Any Temperature |
| title_fullStr | Strain Effects on the Band Gap and Diameter of CdSe Core and CdSe/ZnS Core/Shell Quantum Dots at Any Temperature |
| title_full_unstemmed | Strain Effects on the Band Gap and Diameter of CdSe Core and CdSe/ZnS Core/Shell Quantum Dots at Any Temperature |
| title_short | Strain Effects on the Band Gap and Diameter of CdSe Core and CdSe/ZnS Core/Shell Quantum Dots at Any Temperature |
| title_sort | strain effects on the band gap and diameter of cdse core and cdse zns core shell quantum dots at any temperature |
| url | http://dx.doi.org/10.1155/2019/3764395 |
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