Locally Broken Crystal Symmetry Facilitates Singlet Exciton Fission
| Autor: | Mateusz Snamina, Piotr Petelenz |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Condensed matter physics
Fission 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Photochemical Processes 01 natural sciences Molecular physics Symmetry (physics) 0104 chemical sciences Crystal Pentacene Condensed Matter::Materials Science chemistry.chemical_compound Electric Power Supplies chemistry Superexchange Local symmetry General Materials Science Charge carrier Physical and Theoretical Chemistry 0210 nano-technology Crystallization Order of magnitude |
| Zdroj: | The journal of physical chemistry letters. 7(10) |
| ISSN: | 1948-7185 |
| Popis: | Photovoltaic yield is normally limited to at most two charge carriers per photon. In solid pentacene this limit may be potentially bypassed owing to singlet exciton fission into a pair of triplets. The process occurs via a superexchange mechanism mediated by charge-transfer (CT) configurations and is sensitive to their energies. As demonstrated recently, these strongly depend on the local environment of the two molecules on which the charges reside. Using a multiscale model, here we show that in the crystal bulk approximate local symmetry affects CT state energetics in a way unfavorable for fission, so that at the places where this symmetry is broken the fission probability is enhanced by up to an order of magnitude. These fission-favorable locations entail the vicinity of vacancies, specific impurities, and interfaces, such as crystallite boundaries. Hence, photovoltaic yield might be substantially increased by using nanoscopically disordered pentacene rather than highly ordered specimens. |
| Databáze: | OpenAIRE |
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