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Science (American Association for the Advancement of Science), 2018-05, Vol.360 (6391), p.854-855
Ort / Verlag
United States: The American Association for the Advancement of Science
Erscheinungsjahr
2018
Link zum Volltext
Quelle
Science Online_科学在线
Beschreibungen/Notizen
Scalable synthesis enables long-distance exciton transport in crystalline polymer nanofibers
The conversion of light into usable chemical energy by plants is enabled by the precise spatial arrangement of light-absorbing photosynthetic systems and associated molecular complexes (
1
). In organic solar cells, there is also the need to control intermolecular spacing and molecular orientation, as well as thin-film crystallinity and morphology, so as to enable efficient energy migration and photoconversion (
2
). In an organic solar cell, light absorption creates excitons, tightly bound electron-hole pairs that must be efficiently dissociated into their component charge carriers in order to create an electrical current. Thus, long-range exciton migration must occur from the point of photogeneration to a dissociating site. On page 897 of this issue, Jin
et al.
(
3
) report on a conjugated polymer nanofiber system that yields exciton diffusion lengths greater than 200 nm. In comparison, organic solar cells are typically constructed with materials having exciton diffusion lengths one order of magnitude smaller than this value, which limits device thickness and optical absorption. Their approach exploits a sequential synthesis method that enables measurement of this long exciton diffusion length (see the figure).