Role of impurities in determining the exciton diffusion length in organic semiconductors
| Autor: | Russell J. Holmes, Ian J. Curtin, D. Wayne Blaylock |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Photoluminescence
Materials science Physics and Astronomy (miscellaneous) Exciton Analytical chemistry 02 engineering and technology Photovoltaic effect 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Organic semiconductor Temperature gradient Impurity Sublimation (phase transition) Thin film 0210 nano-technology |
| Zdroj: | Applied Physics Letters. 108:163301 |
| ISSN: | 1077-3118 0003-6951 |
| DOI: | 10.1063/1.4945688 |
| Popis: | The design and performance of organic photovoltaic cells is dictated, in part, by the magnitude of the exciton diffusion length (LD). Despite the importance of this parameter, there have been few investigations connecting LD and materials purity. Here, we investigate LD for the organic small molecule N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-benzidine as native impurities are systematically removed from the material. Thin films deposited from the as-synthesized material yield a value for LD, as measured by photoluminescence quenching, of (3.9 ± 0.5) nm with a corresponding photoluminescence efficiency (ηPL) of (25 ± 1)% and thin film purity of (97.1 ± 1.2)%, measured by high performance liquid chromatography. After purification by thermal gradient sublimation, the value of LD is increased to (4.7 ± 0.5) nm with a corresponding ηPL of (33 ± 1)% and purity of (98.3 ± 0.8)%. Interestingly, a similar behavior is also observed as a function of the deposition boat temperature. Films deposited from the purified... |
| Databáze: | OpenAIRE |
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