Direct Observation of Off‐Stoichiometry‐Induced Phase Transformation of 2D CdSe Quantum Nanosheets
Abstract Crystal structures determine material properties, suggesting that crystal phase transformations have the potential for application in a variety of systems and devices. Phase transitions are more likely to occur in smaller crystals; however, in quantum‐sized semiconductor nanocrystals, the m...
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| Format: | Article |
| Language: | English |
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Wiley
2023-03-01
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| Series: | Advanced Science |
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| Online Access: | https://doi.org/10.1002/advs.202205690 |
| _version_ | 1811160420694622208 |
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| author | Hyeonjong Ma Dongjun Kim Soo Ik Park Back Kyu Choi Gisang Park Hayeon Baek Hyocheol Lee Hyeongseoung Kim Jong‐Sung Yu Won Chul Lee Jungwon Park Jiwoong Yang |
| author_facet | Hyeonjong Ma Dongjun Kim Soo Ik Park Back Kyu Choi Gisang Park Hayeon Baek Hyocheol Lee Hyeongseoung Kim Jong‐Sung Yu Won Chul Lee Jungwon Park Jiwoong Yang |
| author_sort | Hyeonjong Ma |
| collection | DOAJ |
| description | Abstract Crystal structures determine material properties, suggesting that crystal phase transformations have the potential for application in a variety of systems and devices. Phase transitions are more likely to occur in smaller crystals; however, in quantum‐sized semiconductor nanocrystals, the microscopic mechanisms by which phase transitions occur are not well understood. Herein, the phase transformation of 2D CdSe quantum nanosheets caused by off‐stoichiometry is revealed, and the progress of the transformation is directly observed by in situ transmission electron microscopy. The initial hexagonal wurtzite‐CdSe nanosheets with atomically uniform thickness are transformed into cubic zinc blende‐CdSe nanosheets. A combined experimental and theoretical study reveals that electron‐beam irradiation can change the stoichiometry of the nanosheets, thereby triggering phase transformation. The loss of Se atoms induces the reconstruction of surface atoms, driving the transformation from wurtzite‐CdSe(112¯$ar{2}$0) to zinc blende‐CdSe(001) 2D nanocrystals. Furthermore, during the phase transformation, unconventional dynamic phenomena occur, including domain separation. This study contributes to the fundamental understanding of the phase transformations in 2D quantum‐sized semiconductor nanocrystals. |
| first_indexed | 2024-04-10T05:57:01Z |
| format | Article |
| id | doaj.art-23290856148847d28bcb6c008b0091b5 |
| institution | Directory Open Access Journal |
| issn | 2198-3844 |
| language | English |
| last_indexed | 2024-04-10T05:57:01Z |
| publishDate | 2023-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advanced Science |
| spelling | doaj.art-23290856148847d28bcb6c008b0091b52023-03-03T08:59:14ZengWileyAdvanced Science2198-38442023-03-01107n/an/a10.1002/advs.202205690Direct Observation of Off‐Stoichiometry‐Induced Phase Transformation of 2D CdSe Quantum NanosheetsHyeonjong Ma0Dongjun Kim1Soo Ik Park2Back Kyu Choi3Gisang Park4Hayeon Baek5Hyocheol Lee6Hyeongseoung Kim7Jong‐Sung Yu8Won Chul Lee9Jungwon Park10Jiwoong Yang11Department of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu 42988 Republic of KoreaCenter for Nanoparticle Research Institute for Basic Science (IBS) Seoul 08826 Republic of KoreaDepartment of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu 42988 Republic of KoreaCenter for Nanoparticle Research Institute for Basic Science (IBS) Seoul 08826 Republic of KoreaDepartment of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu 42988 Republic of KoreaCenter for Nanoparticle Research Institute for Basic Science (IBS) Seoul 08826 Republic of KoreaDepartment of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu 42988 Republic of KoreaDepartment of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu 42988 Republic of KoreaDepartment of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu 42988 Republic of KoreaDepartment of Mechanical Engineering BK21 FOUR ERICA‐ACE Center Hanyang University Ansan Gyeonggi 15588 Republic of KoreaCenter for Nanoparticle Research Institute for Basic Science (IBS) Seoul 08826 Republic of KoreaDepartment of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST) Daegu 42988 Republic of KoreaAbstract Crystal structures determine material properties, suggesting that crystal phase transformations have the potential for application in a variety of systems and devices. Phase transitions are more likely to occur in smaller crystals; however, in quantum‐sized semiconductor nanocrystals, the microscopic mechanisms by which phase transitions occur are not well understood. Herein, the phase transformation of 2D CdSe quantum nanosheets caused by off‐stoichiometry is revealed, and the progress of the transformation is directly observed by in situ transmission electron microscopy. The initial hexagonal wurtzite‐CdSe nanosheets with atomically uniform thickness are transformed into cubic zinc blende‐CdSe nanosheets. A combined experimental and theoretical study reveals that electron‐beam irradiation can change the stoichiometry of the nanosheets, thereby triggering phase transformation. The loss of Se atoms induces the reconstruction of surface atoms, driving the transformation from wurtzite‐CdSe(112¯$ar{2}$0) to zinc blende‐CdSe(001) 2D nanocrystals. Furthermore, during the phase transformation, unconventional dynamic phenomena occur, including domain separation. This study contributes to the fundamental understanding of the phase transformations in 2D quantum‐sized semiconductor nanocrystals.https://doi.org/10.1002/advs.202205690in situ transmission electron microscopyphase transformationquantum nanosheetsstoichiometrytwo‐dimensional nanocrystals |
| spellingShingle | Hyeonjong Ma Dongjun Kim Soo Ik Park Back Kyu Choi Gisang Park Hayeon Baek Hyocheol Lee Hyeongseoung Kim Jong‐Sung Yu Won Chul Lee Jungwon Park Jiwoong Yang Direct Observation of Off‐Stoichiometry‐Induced Phase Transformation of 2D CdSe Quantum Nanosheets Advanced Science in situ transmission electron microscopy phase transformation quantum nanosheets stoichiometry two‐dimensional nanocrystals |
| title | Direct Observation of Off‐Stoichiometry‐Induced Phase Transformation of 2D CdSe Quantum Nanosheets |
| title_full | Direct Observation of Off‐Stoichiometry‐Induced Phase Transformation of 2D CdSe Quantum Nanosheets |
| title_fullStr | Direct Observation of Off‐Stoichiometry‐Induced Phase Transformation of 2D CdSe Quantum Nanosheets |
| title_full_unstemmed | Direct Observation of Off‐Stoichiometry‐Induced Phase Transformation of 2D CdSe Quantum Nanosheets |
| title_short | Direct Observation of Off‐Stoichiometry‐Induced Phase Transformation of 2D CdSe Quantum Nanosheets |
| title_sort | direct observation of off stoichiometry induced phase transformation of 2d cdse quantum nanosheets |
| topic | in situ transmission electron microscopy phase transformation quantum nanosheets stoichiometry two‐dimensional nanocrystals |
| url | https://doi.org/10.1002/advs.202205690 |
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