Although photovoltaic is one the most promising solution for the future power supply in the world, the issue of storing it is still an open problem. Photoelectrochemical (PEC) cells, which convert solar energy into storable chemical energy directly, is one of the solutions of the storage problem in photovoltaics. In this paper the preparation of freestanding monograin membranes for use in PECs and their characterization is described. The manufacturing process in terms of reproducibility semiconductor particle densities and accessibility for contact formation is optimized. Here especially the etching process reducing the thickness of the polymer film and thereby exposing more of the monograin particles required attention since the etching temperature plays an important role determining the thickness of the. Whereas monograin layer solar cells as yet require particles of at least 45 μm diameter, the monograin membrane process developed here allows to produce such membranes from particles as yet down to 38-45 μm diameter, open and accessible from both sides.