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Title: Ultrafast electron transfer at organic semiconductor interfaces: Importance of molecular orientation

Much is known about the rate of photoexcited charge generation in at organic donor/acceptor (D/A) heterojunctions overaged over all relative arrangements. However, there has been very little experimental work investigating how the photoexcited electron transfer (ET) rate depends on the precise relative molecular orientation between D and A in thin solid films. This is the question that we address in this work. We find that the ET rate depends strongly on the relative molecular arrangement: The interface where the model donor compound copper phthalocyanine is oriented face-on with respect to the fullerene C60 acceptor yields a rate that is approximately 4 times faster than that of the edge-on oriented interface. Our results suggest that the D/A electronic coupling is significantly enhanced in the face-on case, which agrees well with theoretical predictions, underscoring the importance of controlling the relative interfacial molecular orientation.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [2]
  1. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Laboratory, Menlo Park, CA (United States)
  2. SLAC National Accelerator Laboratory, Menlo Park, CA (United States)
  3. Soongsil Univ., Seoul (Korea)
  4. Stanford Univ., Stanford, CA (United States)
Publication Date:
OSTI Identifier:
1215420
Grant/Contract Number:
2011-0031628; KUS-C1-015-21
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 6; Journal Issue: 1; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Research Org:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY organic photovoltaic; core-hole clock; resonant photoemission; charge-transfer state; electron dynamics; resonant Auger