Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl) based electroluminescent devices
The highest occupied and lowest unoccupied states of the new electroluminescent material poly(9,9-dihexyl–9H- fluorene-2,7-diyl) (PPV-D) and polyvinylcarbazole (PVK) are investigated using ultraviolet photoelectron and inverse photoemission spectroscopies. Hole injection barriers are determined for...
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| Format: | Article |
| Language: | English |
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Eastern Macedonia and Thrace Institute of Technology
2014-01-01
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| Series: | Journal of Engineering Science and Technology Review |
| Subjects: | |
| Online Access: | http://www.jestr.org/downloads/volume4/fulltext142011.pdf |
| _version_ | 1811311738928234496 |
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| author | C. Donitsi I. Alexandrescu M. Aleksandrova |
| author_facet | C. Donitsi I. Alexandrescu M. Aleksandrova |
| author_sort | C. Donitsi |
| collection | DOAJ |
| description | The highest occupied and lowest unoccupied states of the new electroluminescent material poly(9,9-dihexyl–9H- fluorene-2,7-diyl) (PPV-D) and polyvinylcarbazole (PVK) are investigated using ultraviolet photoelectron and inverse photoemission spectroscopies. Hole injection barriers are determined for interfaces between indium-tin oxide covered substrates with work function ranging from 4.4 to 4.7 eV and these two polymers. Vacuum level alignment with flat bands away from the interface is found when the interface hole barrier is 0.6 eV or larger. Band bending away from the Fermi level occurs when the hole barrier is smaller than 0.6 eV. This is due to the accumulation charges at the interface with the polymer when the injection barrier is small. The resulting field bends the polymer levels to limit charge incoming in the bulk of the film. The efficiency of the electroluminescent structures is strongly influenced by the different energy levels alignment at the layer interfaces. |
| first_indexed | 2024-04-13T10:24:08Z |
| format | Article |
| id | doaj.art-a1cfd9ece73b49ee8f360fd7fc397654 |
| institution | Directory Open Access Journal |
| issn | 1791-2377 1791-2377 |
| language | English |
| last_indexed | 2024-04-13T10:24:08Z |
| publishDate | 2014-01-01 |
| publisher | Eastern Macedonia and Thrace Institute of Technology |
| record_format | Article |
| series | Journal of Engineering Science and Technology Review |
| spelling | doaj.art-a1cfd9ece73b49ee8f360fd7fc3976542022-12-22T02:50:24ZengEastern Macedonia and Thrace Institute of TechnologyJournal of Engineering Science and Technology Review1791-23771791-23772014-01-01418386Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl) based electroluminescent devicesC. Donitsi0I. Alexandrescu1M. Aleksandrova2University of Craiova, Department of Applied Chemistry, Craiova, Str. Calea Bucuresti, 7.BulgariaUniversity of Craiova, Department of Applied Chemistry, Craiova, Str. Calea Bucuresti, 7.BulgariaTechnical University of Sofia, Department of Microelectronics, Sofia, Kl. Ohridski, 8.BulgariaThe highest occupied and lowest unoccupied states of the new electroluminescent material poly(9,9-dihexyl–9H- fluorene-2,7-diyl) (PPV-D) and polyvinylcarbazole (PVK) are investigated using ultraviolet photoelectron and inverse photoemission spectroscopies. Hole injection barriers are determined for interfaces between indium-tin oxide covered substrates with work function ranging from 4.4 to 4.7 eV and these two polymers. Vacuum level alignment with flat bands away from the interface is found when the interface hole barrier is 0.6 eV or larger. Band bending away from the Fermi level occurs when the hole barrier is smaller than 0.6 eV. This is due to the accumulation charges at the interface with the polymer when the injection barrier is small. The resulting field bends the polymer levels to limit charge incoming in the bulk of the film. The efficiency of the electroluminescent structures is strongly influenced by the different energy levels alignment at the layer interfaces.http://www.jestr.org/downloads/volume4/fulltext142011.pdfpolymer electroluminescent devicesenergy level measurementinterface optimization |
| spellingShingle | C. Donitsi I. Alexandrescu M. Aleksandrova Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl) based electroluminescent devices Journal of Engineering Science and Technology Review polymer electroluminescent devices energy level measurement interface optimization |
| title | Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl) based electroluminescent devices |
| title_full | Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl) based electroluminescent devices |
| title_fullStr | Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl) based electroluminescent devices |
| title_full_unstemmed | Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl) based electroluminescent devices |
| title_short | Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl) based electroluminescent devices |
| title_sort | spectroscopic investigation of the interfaces in new poly 9 9 dihexyl 9h fluorene 2 7 diyl based electroluminescent devices |
| topic | polymer electroluminescent devices energy level measurement interface optimization |
| url | http://www.jestr.org/downloads/volume4/fulltext142011.pdf |
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