Simple organic molecules with permanent dipole moments -amino acids and heterocycleshave been successfully employed in bulk-heterojunction organic solar cells as interlayer between photoactive material and electron contact. A large increase of open-circuit voltage and fill factor could be observed for 4 different polymers as donor material in the photoactive layer. A combination of current-voltage curves, Scanning Kelvin-Probe AFM, ultraviolet photoelectron spectroscopy and electroluminescence measurements as well as numerical simulations were carried out to clarify in detail the underlying mechanisms. All results fully confirm the hypothesis that the main effect is an accumulation of electrons and a depletion of

The novel directional solidification process was developed at ABB for the manufacturing of large single crystal components. In addition to the radiation cooling, typical for the conventional Bridgman technology, an inert gas is injected directly below the furnace baffle. Experiments show that for the Gas Cooling Casting (GCC) process the heat transfer coefficients are significantly higher compared to those in the Bridgman process and are similar to the best LMC practice.

Specific objective functions and algorithms are presented, which by means of dedicated finite element simulation software, calculate optimized control variables for an industrial Bridgman casting furnace. A gradient method and an evolution strategy have been integrated into an efficient optimization tool in order to minimize an objective function which characterizes the quality of directional solidified (DS) or single crystal (SC) turbine blades. The goal is to minimize the manufacturing costs for a desired quality. For a dummy turbine blade geometry, the macrograin structures produced by the optimized withdrawal velocity profile and an equivalent constant velocity, which had the same total process time, are compared. This comparison shows that the developed optimization techniques are applicable to the casting of DS/SC turbine blades.

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