The morphology in organic photovoltaics plays a key role in determining the device efficiency. We propose a method to fabricate bilayer devices with controlled nanostructured interfaces by combining nanoimprinting and lamination techniques. This technique allows us to achieve a network structure of donor-acceptor material with a ϳ80 nm periodicity and ϳ40 nm width. These structures have an abrupt interface between the donor and acceptor materials and show an increased effective interfacial area and photovoltaic performance compared to bilayer solar cells. In contrast to blend films, they will allow an in depth analysis of the influence of morphology on interfacial physical processes.

During the operation period of an organic solar cell different failure mechanisms can occur which limit the lifetime of the device. Among these failure mechanisms the formation of an sshape, where the current density-voltage curve bends towards the origin in the 4 th quadrant, plays an important role. We investigated the origin of the s-shape caused by the holeselective layer using a model system and compared experimental data with numerical simulations. As model system inverted bulk heterojunction solar cells with poly(3hexylthiophene-2,5-diyl):[6,6]-phenyl C 61 butyric acid methyl ester (P3HT:PCBM) as active material and N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-benzidine (TPD) as the hole selective layer co-evaporated with Dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11hexacarbonitrile (HATCN) were used. The crystallization of TPD due to its low glass

No abstract

Analysis of the fibrous composition of feeds by the Goering and Van Soest procedure requires that samples be filtered in the presence of mineral acids and organic solvents. In this process, it is desirable to use a manifold that not only is resistant to these reagents, but also is inexpensive and easy to construct. The new design fits Gooch crucibles tightly and eliminates vacuum leaks and the associated foaming that hampers filtration of difficult samples.