Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 30: Poster: Organic Electronics and Photovoltaics

CPP 30.20: Poster

Dienstag, 8. März 2016, 18:15–21:00, Poster B2

Theoretical core level XPS and NEXAFS investigations of the C₆₀ derivative PCBM: the influence of oxygen adsorption — •Iulia Emilia Brumboiu¹, Leif Ericsson², Rickard Hansson², Ellen Moons², Olle Eriksson¹, and Barbara Brena¹ — ¹Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala, Sweden — ²Department of Engineering and Physics, Karlstad University, SE-65188 Karlstad, Sweden

In recent years, organic photovoltaics (OPVs) have been developing as an alternative to silicon solar cells. Some of the advantages of OPVs are device flexibility, low production cost and low environmental impact. Device efficiencies have recently reached 10%, a limit that makes OPVs competitive on the market. One of the main issues that still needs to be resolved is the stability of the cells. Both the electron donor (organic polymer) and the electron acceptor (fullerene derivative) have been shown to undergo degradation during device functioning. We have addressed in this study one of the possible degradation mechanisms involving the electron acceptor PC₆₀BM . Specifically, we have studied by means of density functional theory (DFT) the possible final products of oxygen adsorption on the C₆₀ cage. Several configurations of PC₆₀BM with oxygen have been analysed from the point of view of the molecular structure, of the O 1s near edge x-ray absorption fine structure (NEXAFS) and of the x-ray photoelectron spectrum (XPS). We show that a joint O 1s XPS and NEXAFS study could provide insight into both the nature of the adsorbate (atomic or molecular oxygen) and the bonding configuration.