Repository logo

Infoscience

  • English
  • French
Log In
Logo EPFL, École polytechnique fédérale de Lausanne

Infoscience

  • English
  • French
Log In
  1. Home
  2. Academic and Research Output
  3. Journal articles
  4. Submolecular Electroluminescence Mapping of Organic Semiconductors
 
research article

Submolecular Electroluminescence Mapping of Organic Semiconductors

Grosse, Christoph
•
Merino, Pablo
•
Roslawska, Anna
Show more
2017
Acs Nano

The electroluminescence of organic films is the central aspect in organic light emitting diodes (OLEDs) and widely used in current display technology. However, its spatial variation on the molecular scale is essentially unexplored. Here, we address this issue by using scanning tunneling microscopy (STM) and present an in-depth study of the electroluminescence from thin C-60 films (<10 monolayers) on Ag(111) and Au(111) surfaces. Similar to an OLED, the metal substrate and STM tip inject complementary charge carriers that may recombine within the molecular film; however, the atomically defined charge injection by the tip enables mapping of the local electroluminescence down to the submolecular scale. We show that the radiative recombination in solid C-60 is restricted to various structural defects, whose emission characteristics can be addressed individually. The emission fine structure reveals a coupling to Jahn-Teller active vibrational modes of C-60, which implies that its parity-forbidden lowest singlet transition becomes locally allowed at the emission centers. At lateral distances of a few nanometers, only a weak emission from tip-induced plasmons is detectable. Their excitation evidences the injection of both charge carrier types and confirms that they are unable to recombine radiatively at positions far from structural defects. Finally, we demonstrate that the molecular orbital pattern visible in electroluminescence maps enables an unambiguous discrimination between the intrinsic radiative recombination of electron hole pairs in the organic film and the technique-related emission of tip-induced plasmons. This capability is essential to consolidate STM as a tool to explore the light generation from organic films on the nanoscale.

  • Details
  • Metrics
Type
research article
DOI
10.1021/acsnano.6b08471
Web of Science ID

WOS:000395357300013

Author(s)
Grosse, Christoph
Merino, Pablo
Roslawska, Anna
Gunnarsson, Olle
Kuhnke, Klaus
Kern, Klaus  
Date Issued

2017

Publisher

American Chemical Society

Published in
Acs Nano
Volume

11

Issue

2

Start page

1230

End page

1237

Subjects

STM-induced luminescence

•

organic semiconductors

•

C-60

•

molecular emission

•

excitons

•

X traps

Editorial or Peer reviewed

REVIEWED

Written at

OTHER

EPFL units
LSEN  
Available on Infoscience
March 27, 2017
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/135889
Logo EPFL, École polytechnique fédérale de Lausanne
  • Contact
  • infoscience@epfl.ch

  • Follow us on Facebook
  • Follow us on Instagram
  • Follow us on LinkedIn
  • Follow us on X
  • Follow us on Youtube
AccessibilityLegal noticePrivacy policyCookie settingsEnd User AgreementGet helpFeedback

Infoscience is a service managed and provided by the Library and IT Services of EPFL. © EPFL, tous droits réservés