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Title: Delocalization Drives Free Charge Generation in Conjugated Polymer Films

Journal Article · · ACS Energy Letters

We demonstrate that the product of photoinduced electron transfer between a conjugated polymer host and a dilute molecular sensitizer is controlled by the structural state of the polymer. Ordered semicrystalline solids exhibit free charge generation, while disordered polymers in the melt phase do not. We use photoluminescence (PL) and time-resolved microwave conductivity (TRMC) measurements to sweep through polymer melt transitions in situ. Free charge generation measured by TRMC turns off upon melting, whereas PL quenching of the molecular sensitizers remains constant, implying unchanged electron transfer efficiency. The key difference is the intermolecular order of the polymer host in the solid state compared to the melt. We propose that this order-disorder transition modulates the localization length of the initial charge-transfer state, which controls the probability of free charge formation.

Research Organization:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC36-08GO28308
OSTI ID:
1426641
Report Number(s):
NREL/JA-5900-70921
Journal Information:
ACS Energy Letters, Vol. 3, Issue 3; ISSN 2380-8195
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 19 works
Citation information provided by
Web of Science

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Cited By (3)

Energetics and Escape of Interchain‐Delocalized Ion Pairs in Nonpolar Media journal January 2019
Slow charge transfer from pentacene triplet states at the Marcus optimum journal November 2019
What is the Binding Energy of a Charge Transfer State in an Organic Solar Cell? journal May 2019

Figures / Tables (4)