Temperature dependence of exciton diffusion in conjugated polymers
| Autor: | Oleksandr V. Mikhnenko, Fabrizio Cordella, Paul W. M. Blom, Jan C. Hummelen, Alexander B. Sieval, Maria Antonietta Loi |
|---|---|
| Přispěvatelé: | Zernike Institute for Advanced Materials |
| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: |
chemistry.chemical_classification
SOLAR-CELLS Photoluminescence Materials science Condensed Matter::Other Diffusion Exciton Analytical chemistry Polymer Conjugated system Condensed Matter::Mesoscopic Systems and Quantum Hall Effect FILMS TRANSPORT Surfaces Coatings and Films ENERGY Condensed Matter::Materials Science chemistry Chemical physics Materials Chemistry Physical and Theoretical Chemistry Spectroscopy |
| Zdroj: | Journal of Physical Chemistry B, 112(37), 11601-11604. AMER CHEMICAL SOC |
| ISSN: | 1520-5207 1520-6106 1089-5647 |
| DOI: | 10.1021/jp8042363 |
| Popis: | The temperature dependence of the exciton dynamics in a conjugated polymer is studied using time-resolved spectroscopy. Photoluminescence decays were measured in heterostructured samples containing a sharp polymer-fullerene interface, which acts as an exciton quenching wall. Using a 1D diffusion model, the exciton diffusion length and diffusion coefficient were extracted in the temperature range of 4-293 K. The exciton dynamics reveal two temperature regimes: in the range of 4-150 K, the exciton diffusion length (coefficient) of approximately 3 nm (approximately 1.5 x 10 (-4) cm2/s) is nearly temperature independent. Increasing the temperature up to 293 K leads to a gradual growth up to 4.5 nm (approximately 3.2 x 10 (-4) cm2/ s). This demonstrates that exciton diffusion in conjugated polymers is governed by two processes: an initial downhill migration toward lower energy states in the inhomogenously broadened density of states, followed by temperature activated hopping. The latter process is switched off below 150 K. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|