Large-area (over 50 cm × 50 cm) freestanding films of colloidal InP/ZnS quantum dots
We propose and demonstrate the fabrication of flexible, freestanding films of InP/ZnS quantum dots (QDs) using fatty acid ligands across very large areas (greater than 50 cm × 50 cm), which have been developed for remote phosphor applications in solid-state lighting. Embedded in a poly(methyl methac...
| Main Authors: | , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2013
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| Online Access: | https://hdl.handle.net/10356/97396 http://hdl.handle.net/10220/10747 |
| _version_ | 1826125572862902272 |
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| author | Panda, Subhendu K. Hickey, Stephen G. Mutlugun, Evren Hernández-Martínez, Pedro Ludwig Eroglu, Cuneyt Coskun, Yasemin Erdem, Talha Sharma, Vijay Kumar Unal, Emre Gaponik, Nikolai Eychmüller, Alexander Demir, Hilmi Volkan |
| author2 | School of Electrical and Electronic Engineering |
| author_facet | School of Electrical and Electronic Engineering Panda, Subhendu K. Hickey, Stephen G. Mutlugun, Evren Hernández-Martínez, Pedro Ludwig Eroglu, Cuneyt Coskun, Yasemin Erdem, Talha Sharma, Vijay Kumar Unal, Emre Gaponik, Nikolai Eychmüller, Alexander Demir, Hilmi Volkan |
| author_sort | Panda, Subhendu K. |
| collection | NTU |
| description | We propose and demonstrate the fabrication of flexible, freestanding films of InP/ZnS quantum dots (QDs) using fatty acid ligands across very large areas (greater than 50 cm × 50 cm), which have been developed for remote phosphor applications in solid-state lighting. Embedded in a poly(methyl methacrylate) matrix, although the formation of stand–alone films using other QDs commonly capped with trioctylphosphine oxide (TOPO) and oleic acid is not efficient, employing myristic acid as ligand in the synthesis of these QDs, which imparts a strongly hydrophobic character to the thin film, enables film formation and ease of removal even on surprisingly large areas, thereby avoiding the need for ligand exchange. When pumped by a blue LED, these Cd-free QD films allow for high color rendering, warm white light generation with a color rendering index of 89.30 and a correlated color temperature of 2298 K. In the composite film, the temperature-dependent emission kinetics and energy transfer dynamics among different-sized InP/ZnS QDs are investigated and a model is proposed. High levels of energy transfer efficiency (up to 80%) and strong donor lifetime modification (from 18 to 4 ns) are achieved. The suppression of the nonradiative channels is observed when the hybrid film is cooled to cryogenic temperatures. The lifetime changes of the donor and acceptor InP/ZnS QDs in the film as a result of the energy transfer are explained well by our theoretical model based on the exciton–exciton interactions among the dots and are in excellent agreement with the experimental results. The understanding of these excitonic interactions is essential to facilitate improvements in the fabrication of photometrically high quality nanophosphors. The ability to make such large-area, flexible, freestanding Cd-free QD films pave the way for environmentally friendly phosphor applications including flexible, surface-emitting light engines. |
| first_indexed | 2024-10-01T06:38:51Z |
| format | Journal Article |
| id | ntu-10356/97396 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T06:38:51Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | ntu-10356/973962020-03-07T12:34:43Z Large-area (over 50 cm × 50 cm) freestanding films of colloidal InP/ZnS quantum dots Panda, Subhendu K. Hickey, Stephen G. Mutlugun, Evren Hernández-Martínez, Pedro Ludwig Eroglu, Cuneyt Coskun, Yasemin Erdem, Talha Sharma, Vijay Kumar Unal, Emre Gaponik, Nikolai Eychmüller, Alexander Demir, Hilmi Volkan School of Electrical and Electronic Engineering School of Physical and Mathematical Sciences We propose and demonstrate the fabrication of flexible, freestanding films of InP/ZnS quantum dots (QDs) using fatty acid ligands across very large areas (greater than 50 cm × 50 cm), which have been developed for remote phosphor applications in solid-state lighting. Embedded in a poly(methyl methacrylate) matrix, although the formation of stand–alone films using other QDs commonly capped with trioctylphosphine oxide (TOPO) and oleic acid is not efficient, employing myristic acid as ligand in the synthesis of these QDs, which imparts a strongly hydrophobic character to the thin film, enables film formation and ease of removal even on surprisingly large areas, thereby avoiding the need for ligand exchange. When pumped by a blue LED, these Cd-free QD films allow for high color rendering, warm white light generation with a color rendering index of 89.30 and a correlated color temperature of 2298 K. In the composite film, the temperature-dependent emission kinetics and energy transfer dynamics among different-sized InP/ZnS QDs are investigated and a model is proposed. High levels of energy transfer efficiency (up to 80%) and strong donor lifetime modification (from 18 to 4 ns) are achieved. The suppression of the nonradiative channels is observed when the hybrid film is cooled to cryogenic temperatures. The lifetime changes of the donor and acceptor InP/ZnS QDs in the film as a result of the energy transfer are explained well by our theoretical model based on the exciton–exciton interactions among the dots and are in excellent agreement with the experimental results. The understanding of these excitonic interactions is essential to facilitate improvements in the fabrication of photometrically high quality nanophosphors. The ability to make such large-area, flexible, freestanding Cd-free QD films pave the way for environmentally friendly phosphor applications including flexible, surface-emitting light engines. 2013-06-27T01:29:29Z 2019-12-06T19:42:12Z 2013-06-27T01:29:29Z 2019-12-06T19:42:12Z 2012 2012 Journal Article Mutlugun, E., Hernandez-Martinez, P. L., Eroglu, C., Coskun, Y., Erdem, T., Sharma, V. K., et al. (2012). Large-Area (over 50 cm × 50 cm) Freestanding Films of Colloidal InP/ZnS Quantum Dots. Nano Letters, 12(8), 3986-3993. 1530-6984 https://hdl.handle.net/10356/97396 http://hdl.handle.net/10220/10747 10.1021/nl301198k en Nano letters © 2012 American Chemical Society. |
| spellingShingle | Panda, Subhendu K. Hickey, Stephen G. Mutlugun, Evren Hernández-Martínez, Pedro Ludwig Eroglu, Cuneyt Coskun, Yasemin Erdem, Talha Sharma, Vijay Kumar Unal, Emre Gaponik, Nikolai Eychmüller, Alexander Demir, Hilmi Volkan Large-area (over 50 cm × 50 cm) freestanding films of colloidal InP/ZnS quantum dots |
| title | Large-area (over 50 cm × 50 cm) freestanding films of colloidal InP/ZnS quantum dots |
| title_full | Large-area (over 50 cm × 50 cm) freestanding films of colloidal InP/ZnS quantum dots |
| title_fullStr | Large-area (over 50 cm × 50 cm) freestanding films of colloidal InP/ZnS quantum dots |
| title_full_unstemmed | Large-area (over 50 cm × 50 cm) freestanding films of colloidal InP/ZnS quantum dots |
| title_short | Large-area (over 50 cm × 50 cm) freestanding films of colloidal InP/ZnS quantum dots |
| title_sort | large area over 50 cm 50 cm freestanding films of colloidal inp zns quantum dots |
| url | https://hdl.handle.net/10356/97396 http://hdl.handle.net/10220/10747 |
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