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Metastable polaron supporting phase in poly-p-phenylene films induced by UV illumination

T. Drori·E. Gershman·C. X. Sheng·Y. Eichen·Z. V. Vardeny·E. Ehrenfreund
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Abstract

We discovered a new metastable polaron-supporting phase in pristine films of a soluble derivative of poly-p-phenylene vinylene (MEH-PPV) that is induced by UV illumination. In the initial un-illuminated phase A, the films do not show long-lived photogenerated polarons. However, prolonged UV illumination for several hours induces a reversible, me-tastable phase B that shows abundant long-lived photogenerated polarons. Phase B films transform back to the original phase A within 1/2 hour in the dark at room temperature. We propose a reversible mechanism in which UV illumination creates metastable deep defects that substantially increase the photogenerated polaron lifetime.

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T. Drori, E. Gershman, C. X. Sheng, Y. Eichen, Z. V. Vardeny, E. Ehrenfreund. 2006-08-22. Metastable polaron supporting phase in poly-p-phenylene films induced by UV illumination. https://doi.org/10.1103/physrevb.76.033203

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