Harald Hoppe

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In this paper we investigate the potential of light trapping with diffraction gratings for organic solar cells. The architecture of the solar cell is based on conjugated polymers and a buckminsterfullerene derivative (PCBM), forming an interpenetrating donor-acceptor-network. The motivation for light trapping is the small absorptance of the photoactive(More)
While an increasing number of operation planning systems enable surgeons to preoperatively define and plan complex surgical interventions, providing these planning data intraoperatively in a reasonable way is still a challenging task. We have developed a new system using projector based augmented reality for the intraoperative visualization of(More)
The influence of crystallinity on exciton diffusion and fullerene distribution was investigated by blending amorphous and semicrystalline copolymers. We measured exciton diffusion and fluorescence quenching in such blends by dispersing fullerene molecules into them. We find that the diffusion length is more than two times higher in the semicrystalline(More)
We report on the degradation of organic photovoltaic (OPV) cells in both indoor and outdoor environments. Eight different research groups contributed state of the art OPV cells to be studied at Pomona College. Power conversion efficiency and fill factor were determined from IV curves collected at regular intervals over six to eight months. Similarly(More)