Competitive Effects of Oxidation and Quantum Confinement on Modulation of the Photophysical Properties of Metallic-Phase Tungsten Dichalcogenide Quantum Dots
Metallic-phase transition metal dichalcogenide quantum dots (TMDs-<i>m</i>QDs) have been reported in recent years. However, a dominant mechanism for modulating their intrinsic exciton behaviors has not been determined yet as their size is close to the Bohr radius. Herein, we demonstrate...
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MDPI AG
2023-07-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/13/14/2075 |
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| author | Bo-Hyun Kim Jun Yong Yang Kwang Hyun Park DongJu Lee Sung Ho Song |
| author_facet | Bo-Hyun Kim Jun Yong Yang Kwang Hyun Park DongJu Lee Sung Ho Song |
| author_sort | Bo-Hyun Kim |
| collection | DOAJ |
| description | Metallic-phase transition metal dichalcogenide quantum dots (TMDs-<i>m</i>QDs) have been reported in recent years. However, a dominant mechanism for modulating their intrinsic exciton behaviors has not been determined yet as their size is close to the Bohr radius. Herein, we demonstrate that the oxidation effect prevails over quantum confinement on metallic-phase tungsten dichalcogenide QDs (WX<sub>2</sub>-<i>m</i>QDs; X = S, Se) when the QD size becomes larger than the exciton Bohr radius. WX<sub>2</sub>-<i>m</i>QDs with a diameter of ~12 nm show an obvious change in their photophysical properties when the pH of the solution changes from 2 to 11 compared to changing the size from ~3 nm. Meanwhile, we found that quantum confinement is the dominant function for the optical spectroscopic results in the WX<sub>2</sub>-<i>m</i>QDs with a size of ~3 nm. This is because the oxidation of the larger WX<sub>2</sub>-<i>m</i>QDs induces sub-energy states, thus enabling excitons to migrate into the lower defect energy states, whereas in WX<sub>2</sub>-<i>m</i>QDs with a size comparable to the exciton Bohr radius, protonation enhances the quantum confinement. |
| first_indexed | 2024-03-11T00:45:52Z |
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| id | doaj.art-47439582b8f7409cb8c3caca97bce250 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-11T00:45:52Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
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| series | Nanomaterials |
| spelling | doaj.art-47439582b8f7409cb8c3caca97bce2502023-11-18T20:45:38ZengMDPI AGNanomaterials2079-49912023-07-011314207510.3390/nano13142075Competitive Effects of Oxidation and Quantum Confinement on Modulation of the Photophysical Properties of Metallic-Phase Tungsten Dichalcogenide Quantum DotsBo-Hyun Kim0Jun Yong Yang1Kwang Hyun Park2DongJu Lee3Sung Ho Song4Division of Advanced Materials Engineering, Center for Advanced Powder Materials and Parts, Kongju National University, Cheonan 32588, Republic of KoreaDivision of Advanced Materials Engineering, Center for Advanced Powder Materials and Parts, Kongju National University, Cheonan 32588, Republic of KoreaDivision of Advanced Materials Engineering, Center for Advanced Powder Materials and Parts, Kongju National University, Cheonan 32588, Republic of KoreaDepartment of Advanced Materials Engineering, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju 34057, Republic of KoreaDivision of Advanced Materials Engineering, Center for Advanced Powder Materials and Parts, Kongju National University, Cheonan 32588, Republic of KoreaMetallic-phase transition metal dichalcogenide quantum dots (TMDs-<i>m</i>QDs) have been reported in recent years. However, a dominant mechanism for modulating their intrinsic exciton behaviors has not been determined yet as their size is close to the Bohr radius. Herein, we demonstrate that the oxidation effect prevails over quantum confinement on metallic-phase tungsten dichalcogenide QDs (WX<sub>2</sub>-<i>m</i>QDs; X = S, Se) when the QD size becomes larger than the exciton Bohr radius. WX<sub>2</sub>-<i>m</i>QDs with a diameter of ~12 nm show an obvious change in their photophysical properties when the pH of the solution changes from 2 to 11 compared to changing the size from ~3 nm. Meanwhile, we found that quantum confinement is the dominant function for the optical spectroscopic results in the WX<sub>2</sub>-<i>m</i>QDs with a size of ~3 nm. This is because the oxidation of the larger WX<sub>2</sub>-<i>m</i>QDs induces sub-energy states, thus enabling excitons to migrate into the lower defect energy states, whereas in WX<sub>2</sub>-<i>m</i>QDs with a size comparable to the exciton Bohr radius, protonation enhances the quantum confinement.https://www.mdpi.com/2079-4991/13/14/2075quantum dotstransition metal dichalcogenidequantum confinementphotoluminescenceoptical property |
| spellingShingle | Bo-Hyun Kim Jun Yong Yang Kwang Hyun Park DongJu Lee Sung Ho Song Competitive Effects of Oxidation and Quantum Confinement on Modulation of the Photophysical Properties of Metallic-Phase Tungsten Dichalcogenide Quantum Dots Nanomaterials quantum dots transition metal dichalcogenide quantum confinement photoluminescence optical property |
| title | Competitive Effects of Oxidation and Quantum Confinement on Modulation of the Photophysical Properties of Metallic-Phase Tungsten Dichalcogenide Quantum Dots |
| title_full | Competitive Effects of Oxidation and Quantum Confinement on Modulation of the Photophysical Properties of Metallic-Phase Tungsten Dichalcogenide Quantum Dots |
| title_fullStr | Competitive Effects of Oxidation and Quantum Confinement on Modulation of the Photophysical Properties of Metallic-Phase Tungsten Dichalcogenide Quantum Dots |
| title_full_unstemmed | Competitive Effects of Oxidation and Quantum Confinement on Modulation of the Photophysical Properties of Metallic-Phase Tungsten Dichalcogenide Quantum Dots |
| title_short | Competitive Effects of Oxidation and Quantum Confinement on Modulation of the Photophysical Properties of Metallic-Phase Tungsten Dichalcogenide Quantum Dots |
| title_sort | competitive effects of oxidation and quantum confinement on modulation of the photophysical properties of metallic phase tungsten dichalcogenide quantum dots |
| topic | quantum dots transition metal dichalcogenide quantum confinement photoluminescence optical property |
| url | https://www.mdpi.com/2079-4991/13/14/2075 |
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