Abstract: The present invention relates to a photosensitive organic semiconductor composition comprising an organic p-type semiconductor pigment with a p-type conducting polymer, wherein the ionization potentials of the organic p-type semiconductor pigment and the p-type conducting polymer are nominally equivalent and a photosensitive organic semiconductor composition comprising an organic n-type semiconductor pigment with an n-type conducting polymer, wherein the electron affinities of the organic semiconductor pigment and the conducting polymer are nominally equivalent. The present invention also relates to a p/n heterojunction utilizing the photosensitive organic semiconductor compositions.

Abstract: A mixer for preparing silver halide grains for photographic use has upper and lower impellers housed in a draft tube. The bottom impeller has flat blades for micromixing silver and halide reactants introduced into the bottom of the draft tube. The upper impeller has pitched blades for macromixing the bulk fluid. The impellers are spaced apart at least the distance of their diameters so that the upper and lower impellers operate independently of one another so that micromixing is independent of macromixing. A flow disrupter structurally associated with the draft tube and positioned above the top impeller prevents vortexing of the fluid during mixing. Baffles may be provided in the draft tube to discourage vortexing.