Photophysical and electrolumine scent properties of hyperbranched polyfluorenes
文献类型：期刊论文
| 作者 | Ding, L; Bo, ZS; Chu, QH; Li, J; Dai, LM; Pang, Y; Karasz, FE; Durstock, ME |
| 刊名 | MACROMOLECULAR CHEMISTRY AND PHYSICS
 |
| 出版日期 | 2006-05-19 |
| 卷号 | 207期号:10页码:870-878 |
| 关键词 | Electroluminescence Energy Transfer Exciton Confinement Density Hyperbranched Polyfluorene Photoluminescence Structures |
| ISSN号 | 1022-1352 |
| DOI | 10.1002/macp.200600055 |
| 英文摘要 | Properties of a series of hyperbranched polyfluorenes were investigated. Increasing the benzene "cross-point" density blue-shifts the absorption and PL since the crosspoints interrupt pi-electron conjugation, decreasing conjugation length, and thus increasing chromophore band gap. The relative intensity of S-10 --> S-00 transition in PL increases with crosspoint density increase, indicating that the energy and the energy distribution of vibronic transitions were controlled by hyperbranch structure. When the polymer solution is cooled down, the lattice vibration is reduced and the effective conjugation length (coherence length for electron wavefunction) is increased, thus causing bathochromic shift in absorption and PL. These polymers do not favor excimer formation in solution due to their remarkable rigidity and extra-large molecular size. With increase in crosspoint density, LED color changed from green to violet In double-layer LEDs, PPV not only improves hole injection/ transport but also contributes to device emission through its bulk emission and interfacial emission as a result of interfacial energy transfer. Higher electrical field favors interfacial energy transfer probably by facilitating hole-electron recombination and by encouraging the excitons formed in polyfluorene layer to migrate to the interface and to further diffuse into PPV layer. The polymer with more crosspoints shows higher EL efficiency. The crosspoints interrupt pi-electron conjugation, isolate excitons and inhibit intrachain exciton annihilation. They can also increase rigidity of the macromolecular backbone, and the large spatial hindrance of these macromolecules makes the molecular packing very difficult, thus decreasing interchain exciton annihilation. All these structural features help to increase exciton lifetime and improve LED performance. |
| 语种 | 英语 |
| WOS记录号 | WOS:000237944000003 |
| 出版者 | WILEY-V C H VERLAG GMBH |
| 源URL | [http://ir.iccas.ac.cn/handle/121111/58097]  |
| 专题 | 中国科学院化学研究所 |
| 通讯作者 | Ding, L |
| 作者单位 | 1.Univ Massachusetts, Dept Polymer Sci & Engn, Amherst, MA 01003 USA 2.Univ Dayton, Dept Mat Engn, Dayton, OH 45469 USA 3.Chinese Acad Sci, Inst Chem, State Key Lab Polymer Phys & Chem, Beijing 100080, Peoples R China 4.Univ Akron, Dept Chem, Akron, OH 44325 USA 5.USAF, Res Lab, Polymer Branch, Wright Patterson AFB, OH 45433 USA |
| 推荐引用方式 GB/T 7714 | Ding, L,Bo, ZS,Chu, QH,et al. Photophysical and electrolumine scent properties of hyperbranched polyfluorenes[J]. MACROMOLECULAR CHEMISTRY AND PHYSICS,2006,207(10):870-878. |
| APA | Ding, L.,Bo, ZS.,Chu, QH.,Li, J.,Dai, LM.,...&Durstock, ME.(2006).Photophysical and electrolumine scent properties of hyperbranched polyfluorenes.MACROMOLECULAR CHEMISTRY AND PHYSICS,207(10),870-878. |
| MLA | Ding, L,et al."Photophysical and electrolumine scent properties of hyperbranched polyfluorenes".MACROMOLECULAR CHEMISTRY AND PHYSICS 207.10(2006):870-878. |
入库方式： OAI收割
来源：化学研究所
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