Regensburg 2010 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 19: Organic Electronics and Photovoltaics I

CPP 19.6: Vortrag

Dienstag, 23. März 2010, 11:00–11:15, H37

Hexaazatriphenylene and hexaazatrinaphthylene derivatives as electron transport materials in organic solar cells — •Christiane Falkenberg¹, Martin Baumgarten², Ralph Rieger², Selina Olthof¹, Karl Leo¹, Moritz Riede¹, and Klaus Müllen² — ¹Institut für Angewandte Photophysik, TU Dresden, 01069 Dresden — ²MPI für Polymerforschung, 55128 Mainz

There is increasing interest in molecularly doped organic materials for the fabrication of efficient organic electronic devices. In small molecule organic solar cells, the so-called p-i-n concept is advantageous for the independent optimization of electrical and optical properties. Here, the absorbing donor-acceptor heterojunction is sandwiched between a p-doped hole transport layer and an n-doped electron transport layer. The design of suitable functional molecules for the transport layers is currently an important issue, however, the choice of available wide-gap materials for the n-side of organic solar cells is very limited. Here, we investigate hexaazatriphenylene and hexaazatrinaphthylene derivatives as substitutes for the common electron transport materials C₆₀ or BPhen and BCP. Having bandgaps of > 2.7eV the new materials are transparent which, in combination with a suitable position of the energy levels, enables exciton blocking. Furthermore molecular doping with either acridine orange base (AOB) or NDN1 (Novaled AG) leads to an increase of the conductivity by several orders of magnitude, reaching values beyond 1·10⁻⁶ S/cm. Altogether the beneficial optical and electrical properties allow the fabrication of organic solar cells with increased efficiency compared to the standard devices.