A multijunction solar cell including an upper first solar subcell having a first band gap and positioned for receiving an incoming light beam; a second solar subcell disposed below and adjacent to and lattice matched with said upper first solar subcell, and having a second band gap smaller than said first band gap; wherein the upper first solar subcell covers less than the entire upper surface of the second solar subcell, leaving an exposed portion of the second solar subcell that lies in the path of the incoming light beam.

A solar cell of an embodiment includes: a p-electrode in which a first p-electrode and a second p-electrode are laminated; a p-type light-absorbing layer in direct contact with the first p-electrode; an n-type layer in direct contact with the p-type light-absorbing layer; and an n-electrode. The first p-electrode is disposed between the p-type light-absorbing layer and the second p-electrode. The p-type light-absorbing layer is disposed between the n-type layer and the first p-electrode. The n-type layer is disposed between the p-type light-absorbing layer and the n-electrode. The first p-electrode includes a metal oxide containing Sn as a main component.

A solar cell of an embodiment includes: a p-electrode in which a first p-electrode and a second p-electrode are laminated; a p-type light-absorbing layer in direct contact with the first p-electrode; an n-type layer in direct contact with the p-type light-absorbing layer; and an n-electrode. The first p-electrode is disposed between the p-type light-absorbing layer and the second p-electrode. The p-type light-absorbing layer is disposed between the n-type layer and the first p-electrode. The n-type layer is disposed between the p-type light-absorbing layer and the n-electrode. The first p-electrode includes a metal oxide containing Sn as a main component.

A method of fabricating a four junction solar cell having an upper first solar subcell composed of a semiconductor material including aluminum and having a first band gap; a second solar subcell adjacent to said first solar subcell and composed of a semiconductor material having a second band gap smaller than the first band gap and being lattice matched with the upper first solar subcell; a third solar subcell adjacent to said second solar subcell and composed of a semiconductor material having a third band gap smaller than the second band gap and being lattice matched with the second solar subcell; and a fourth solar subcell adjacent to and lattice matched with said third solar subcell and composed of a semiconductor material having a fourth band gap smaller than the third band gap; wherein the fourth subcell has a direct bandgap of greater than 0.75 eV.

A method of fabricating a four junction solar cell having an upper first solar subcell composed of a semiconductor material including aluminum and having a first band gap; a second solar subcell adjacent to said first solar subcell and composed of a semiconductor material having a second band gap smaller than the first band gap and being lattice matched with the upper first solar subcell; a third solar subcell adjacent to said second solar subcell and composed of a semiconductor material having a third band gap smaller than the second band gap and being lattice matched with the second solar subcell; and a fourth solar subcell adjacent to and lattice matched with said third solar subcell and composed of a semiconductor material having a fourth band gap smaller than the third band gap; wherein the fourth subcell has a direct bandgap of greater than 0.75 eV.

A solar cell of an embodiment includes: a substrate; an n-electrode; an n-type layer; a p-type light absorption layer which is a semiconductor of a Cu-based oxide; and a p-electrode. The n-electrode is disposed between the substrate and the n-type layer. The n-type layer is disposed between the n-electrode and the p-type light absorption layer. The p-type light absorption layer is disposed between the n-type layer and the p-electrode. The n-type layer is disposed closer to a light incident side than the p-type light absorption layer. The substrate is a single substrate included in the solar cell.

A solar cell of an embodiment includes: a substrate; an n-electrode; an n-type layer; a p-type light absorption layer which is a semiconductor of a Cu-based oxide; and a p-electrode. The n-electrode is disposed between the substrate and the n-type layer. The n-type layer is disposed between the n-electrode and the p-type light absorption layer. The p-type light absorption layer is disposed between the n-type layer and the p-electrode. The n-type layer is disposed closer to a light incident side than the p-type light absorption layer. The substrate is a single substrate included in the solar cell.

An integrated tandem solar cell includes a first solar cell including a rear electrode, a light absorption layer disposed on the rear electrode, and a buffer layer disposed on the light absorption layer; a recombination layer including a first transparent conductive layer disposed on the buffer layer; a nanoparticle layer that is transparent and conductive, that is disposed on the first transparent conductive layer, and that planarizes the first solar cell; and a second transparent conductive layer disposed on the nanoparticle layer; and a second solar cell that is a perovskite solar cell including a perovskite layer and that is disposed on and bonded to the second transparent conductive layer of the recombination layer. The recombination layer electrically joins the first and second solar cells and planarizes the first solar cell so that the second solar cell is uniformly deposited in all regions thereof.

An integrated tandem solar cell includes a first solar cell including a rear electrode, a light absorption layer disposed on the rear electrode, and a buffer layer disposed on the light absorption layer; a recombination layer including a first transparent conductive layer disposed on the buffer layer; a nanoparticle layer that is transparent and conductive, that is disposed on the first transparent conductive layer, and that planarizes the first solar cell; and a second transparent conductive layer disposed on the nanoparticle layer; and a second solar cell that is a perovskite solar cell including a perovskite layer and that is disposed on and bonded to the second transparent conductive layer of the recombination layer. The recombination layer electrically joins the first and second solar cells and planarizes the first solar cell so that the second solar cell is uniformly deposited in all regions thereof.

A solar cell device includes a supporting substrate, and an epitaxial active structure that is disposed on the supporting substrate. The epitaxial active structure has a bottom surface adjacent to the supporting substrate and a top surface opposite to the bottom surface, and is formed with an isolation section that extends from the top surface to the bottom surface. A method for producing the solar cell device is also disclosed.