The invention pertains to a solar cell unit comprising a black electrode, a photovoltaic layer, front electrode, and a transparent top layer, characterised in that on top of the top layer at least one removable transparent polymer film is present. Preferably, 2-10, more preferably 3-5, removable transparent polymer films stacked one on top of the other are present on the top layer. On the bottom side the transparent polymer films may be provided with an adhesive layer which displays greater adhesion to the polymer film itself than to the underlying layer. Preferably, the solar cell unit is also provided with a substrate at the back of the back electrode. The presence of a transparent removable top layer enables easy removal of a surface it has got dirty. |