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Title: The influence of oxygen adsorption on the NEXAFS and core-level XPS spectra of the C{sub 60} derivative PCBM

Fullerenes have been a main focus of scientific research since their discovery due to the interesting possible applications in various fields like organic photovoltaics (OPVs). In particular, the derivative [6,6]-phenyl-C{sub 60}-butyric acid methyl ester (PCBM) is currently one of the most popular choices due to its higher solubility in organic solvents compared to unsubstituted C{sub 60}. One of the central issues in the field of OPVs is device stability, since modules undergo deterioration (losses in efficiency, open circuit voltage, and short circuit current) during operation. In the case of fullerenes, several possibilities have been proposed, including dimerization, oxidation, and impurity related deterioration. We have studied by means of density functional theory the possibility of oxygen adsorption on the C{sub 60} molecular moiety of PCBM. The aim is to provide guidelines for near edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) measurements which can probe the presence of atomic or molecular oxygen on the fullerene cage. By analysing several configurations of PCBM with one or more adsorbed oxygen atoms, we show that a joint core level XPS and O1s NEXAFS investigation could be effectively used not only to confirm oxygen adsorption but also to pinpoint the bonding configurationmore » and the nature of the adsorbate.« less
Authors:
; ;  [1] ; ; ;  [2]
  1. Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala (Sweden)
  2. Department of Engineering and Physics, Karlstad University, SE-65188 Karlstad (Sweden)
Publication Date:
OSTI Identifier:
22416074
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; ADSORPTION; ATOMS; BUTYRIC ACID; COMPARATIVE EVALUATIONS; DENSITY FUNCTIONAL METHOD; DIMERIZATION; EFFICIENCY; ELECTRIC POTENTIAL; ESTERS; FINE STRUCTURE; FULLERENES; ORGANIC SOLVENTS; OXIDATION; PHASE STABILITY; PHOTOVOLTAIC EFFECT; SOLUBILITY; X-RAY PHOTOELECTRON SPECTROSCOPY; X-RAY SPECTROSCOPY