Regensburg 2010 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 19: Organic Electronics and Photovoltaics I
CPP 19.6: Talk
Tuesday, March 23, 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.