Abstract: A multi-junction solar cell having at least three partial cells having an emitter and a base. The first partial cell comprises a first layer of a compound containing at least the elements GaInP, and the energy band gap of the first layer is greater than 1.75 eV, and wherein the second partial cell has a second layer of a compound having at least the elements GaAs and the lattice constant of the second layer is in the range between 5.635 ? and 5.675 ?, and wherein the third partial cell has a third layer of a compound having at least the elements GaInAs and the energy band gap of the third layer is smaller than 1.25 eV and the lattice constant of the third layer is greater than 5.700 ?.