Method for improving contact resistance of a multi-junction solar cell

A method for improving a contact resistance of a multi-junction solar cell having a front and a back and multiple subcells, the method comprising:

• a) delivering the multi-junction solar cell with a front contact and a back contact, the front contact and/or the back contact being in grid, strip or transparent form,
• b) electrically contact-connecting one region of the back contact to a contact device that is electrically connected to one pole of a voltage source, and the front contact or another region of the back contact, which is electrically insulated from the region, to another contact device, which is electrically connected to another pole of the voltage source,
• c) applying a voltage directed against a forward direction of the multi-junction solar cell to the front contact and the back contact using the voltage source, the applied voltage being smaller in magnitude than a breakdown voltage of the multi-junction solar cell,
• d) guiding at least one point light source over the front and/or the back of the multi-junction solar cell while the voltage is applied, one or more sections of a subregion of the front or back being illuminated, with a result that a flow of current is induced in a respective subregion and acts on the respective subregion, and the one or more sections of the subregion being simultaneously illuminated with multiple light beams having different wavelength ranges by the point light source.