Dr. Stefan Kraner

Research Interests

Tailoring amphiphilic organic molecules for self assembled photovoltaic materials

Organic photovoltaics represent a cost-effective, renewable and therefore future-oriented energy supply. However, the power conversion efficiencies of this technology are still too low for the large-scale use of organic photovoltaics. The reason for the low efficiency can be attributed to the high voltage losses caused by the required donor-acceptor system and the low charge carrier mobility in the photoactive material.

In the current project, a concept is being tested which provides an ideal morphology for organic solar cells. The core of the concept consists in the self-assembly of amphiphilic organic donor acceptor molecules into a phase-separated bilayer, leading to donor and acceptor phases with a crystalline structure which improves the charge carrier mobility by order of magnitudes. In addition, the donor-acceptor interface is defined intramolecularly via a spacer molecule, thus enabling the donor-acceptor interface to be optimized at the molecular level. This ideal morphology presumably leads to very high power conversion efficiencies.