We separate electrons with an electron membrane:
a layer that is highly conductive for electrons but not for holes.

This is often called an emitter in a conventional solar cell.

The electric field present in a pn junction in the dark, usually considered a prerequisite for the operation of a solar cell, is in fact more an accompanying phenomenon of a structure required for other reasons and not an essential property of a solar cell.

Peter Wurfel, Physics of Solar Cells