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Field-induced exciton dissociation in PTB7-based organic solar cells

Gerhard, Marina; Arndt, Andreas P.; Bilal, Mühenad; Lemmer, Uli; Koch, Martin; Howard, Ian A.

Abstract (englisch):
The physics of charge separation in organic semiconductors is a topic of ongoing research of relevance to material and device engineering. Herein, we present experimental observations of the field and temperature dependence of charge separation from singlet excitons in PTB7 and PC71BM, and from charge-transfer states created across interfaces in PTB7/PC71BM bulk heterojunction solar cells. We obtain this experimental data by time-resolving the near infrared emission of the states from 10 K to room temperature and electric fields from 0 to 2.5MVcm−1. Examining how the luminescence is quenched by field and temperature gives direct insight into the underlying physics. We observe that singlet excitons can be split by high fields, and that disorder broadens the high threshold fields needed to split the excitons. Charge-transfer (CT) states, on the other hand, can be separated by both field and temperature. Also, the data imply a strong reduction of the activation barrier for charge splitting from the CT state relative to the exciton state. The observations provided herein of the field-dependent separation of CT states as a function of te ... mehr

Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT)
Lichttechnisches Institut (LTI)
Publikationstyp Zeitschriftenaufsatz
Jahr 2017
Sprache Englisch
Identifikator DOI: 10.1103/PhysRevB.95.195301
ISSN: 2469-9950, 2469-9969, 0163-1829, 0556-2805, 1094-1622, 1095-3795, 1098-0121, 1550-235X
KITopen ID: 1000070136
HGF-Programm 43.23.04; LK 01
Erschienen in Physical review / B
Band 95
Heft 19
Seiten Art.Nr. 195301
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