skip to main content

Title: Electronic transitions and band offsets in C{sub 60}:SubPc and C{sub 60}:MgPc on MoO{sub 3} studied by modulated surface photovoltage spectroscopy

Electronic transitions at interfaces between MoO{sub 3} layers and organic layers of C{sub 60}, SubPc, MgPc, and nano-composite layers of SubPc:C{sub 60} and MgPc:C{sub 60} have been studied by modulated surface photovoltage (SPV) spectroscopy. For all systems, time dependent and modulated SPV signals pointed to dissociation of excitons at the MoO{sub 3}/organic layer interfaces with a separation of holes towards MoO{sub 3}. The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps (E{sub HL}) of C{sub 60}, SubPc, and MgPc and the effective E{sub HL} of SubPc:C{sub 60} and MgPc:C{sub 60} were measured. The offsets between the LUMO (ΔE{sub L}) or HOMO (ΔE{sub H}) bands were obtained with high precision and amounted to 0.33 or 0.73 eV for SubPc:C{sub 60}, respectively, and to −0.33 or 0.67 eV for MgPc:C{sub 60}, respectively. Exponential tails below E{sub HL} and most pronounced sub-bandgap transitions were characterized and ascribed to disorder and transitions from HOMO bands to unoccupied defect states.
Authors:
; ;  [1]
  1. Institut für Heterogene Materialsysteme, Helmholtz-Zentrum Berlin für Materialien und Energie, Lise-Meitner Campus, Hahn-Meitner-Platz 1, 14109 Berlin (Germany)
Publication Date:
OSTI Identifier:
22490805
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCURACY; DISSOCIATION; EXCITONS; FULLERENES; HOLES; INTERFACES; LAYERS; MOLECULAR ORBITAL METHOD; MOLYBDENUM OXIDES; SIGNALS; SPECTROSCOPY; SURFACES; TIME DEPENDENCE