There is provided a method of producing a photovoltaic device comprising a photoactive region comprising a layer of perovskite material, wherein the layer of perovskite material is disposed on a surface that has a roughness average (R.sub.a) or root mean square roughness (R.sub.rms) of greater than or equal to 50 nm. The method comprises using vapour deposition to deposit a substantially continuous and conformal solid layer comprising one or more initial precursor compounds of the perovskite material, and subsequently treating the solid layer with one or more further precursor compounds to form a substantially continuous and conformal solid layer of the perovskite material on the rough surface. There is also provided a photovoltaic device comprising a photoactive region comprising a layer of perovskite material disposed using the method.

A solar cell element includes a first electrode, a second electrode, a light-absorbing layer, and a first carrier transporter. The light-absorbing layer is located between the first electrode and the second electrode. The first carrier transporter is located between the light-absorbing layer and the first electrode. The first carrier transporter includes a first semiconductor layer of a first conduction type and a first carrier introducing layer stacked in a direction from the light-absorbing layer toward the first electrode. The first carrier introducing layer is in contact with a surface of the first semiconductor layer nearer the first electrode. The first carrier introducing layer has an ionization potential smaller than an electron affinity of the first semiconductor layer.

A solar cell element includes a first electrode, a second electrode, a light-absorbing layer, and a first carrier transporter. The light-absorbing layer is located between the first electrode and the second electrode. The first carrier transporter is located between the light-absorbing layer and the first electrode. The first carrier transporter includes a first semiconductor layer of a first conduction type and a first carrier introducing layer stacked in a direction from the light-absorbing layer toward the first electrode. The first carrier introducing layer is in contact with a surface of the first semiconductor layer nearer the first electrode. The first carrier introducing layer has an ionization potential smaller than an electron affinity of the first semiconductor layer.

A stacked monolithic multijunction solar cell, which includes a first subcell having a p-n junction with an emitter layer and a base layer, the thickness of the emitter layer being less than the thickness of the base layer at least by a factor of ten, and the first subcell comprising a substrate having a semiconductor material from the groups III and V or a substrate from the group IV, and which further includes a second subcell arranged on the first subcell and a third subcell arranged on the second subcell, the two subcells each including an emitter layer and a base layer, and a tunnel diode and a back side field layer each being formed between the subcells, the thickness of the emitter layer being greater than the thickness of the base layer in each case between the second subcell and in the third subcell.

A stacked monolithic multijunction solar cell, which includes a first subcell having a p-n junction with an emitter layer and a base layer, the thickness of the emitter layer being less than the thickness of the base layer at least by a factor of ten, and the first subcell comprising a substrate having a semiconductor material from the groups III and V or a substrate from the group IV, and which further includes a second subcell arranged on the first subcell and a third subcell arranged on the second subcell, the two subcells each including an emitter layer and a base layer, and a tunnel diode and a back side field layer each being formed between the subcells, the thickness of the emitter layer being greater than the thickness of the base layer in each case between the second subcell and in the third subcell.

A four junction solar cell and its method of manufacture including an upper first solar subcell composed of a semiconductor material 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; a graded interlayer adjacent to the third solar subcell and having a fourth band gap greater than the third band gap; and a bottom solar subcell adjacent to the graded interlayer and being lattice mismatched from the third solar subcell and having a fifth band gap smaller than the fifth band gap, wherein the selection of composition of the subcells and their band gaps maximizes the efficiency of the solar cell at a predetermined temperature value (between 28 and 70 degrees Centigrade) at a predetermined time after the initial deployment in space, (the time of the initial deployment being referred to as “beginning-of-life (BOL)”), such predetermined time being referred to as the “end-of-life (EOL)” time, and such time being at least one year.

A four junction solar cell and its method of manufacture including an upper first solar subcell composed of a semiconductor material 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; a graded interlayer adjacent to the third solar subcell and having a fourth band gap greater than the third band gap; and a bottom solar subcell adjacent to the graded interlayer and being lattice mismatched from the third solar subcell and having a fifth band gap smaller than the fifth band gap, wherein the selection of composition of the subcells and their band gaps maximizes the efficiency of the solar cell at a predetermined temperature value (between 28 and 70 degrees Centigrade) at a predetermined time after the initial deployment in space, (the time of the initial deployment being referred to as “beginning-of-life (BOL)”), such predetermined time being referred to as the “end-of-life (EOL)” time, and such time being at least one year.

A solar panel includes a silicon cells submodule of silicon based cells, a front transparent plate and a backsheet. The backsheet is arranged with at least a first conductive pattern that is connected to rear surface electrical contacts on each of the silicon cells. A thin film photovoltaic submodule is arranged between the front transparent plate and the silicon cells, and includes thin film cells in an arrangement with two photovoltaic submodule contacts that connect to a second conductive pattern on the backsheet. The backsheet is arranged for four-terminal wiring with the first pattern for the silicon cells and the second pattern for the thin film cells. The thin film cells are disposed in a first group of cells and in at least a second group of cells, each connected in series. The first group is connected in parallel with the second group, between the photovoltaic submodule contacts.

A solar panel includes a silicon cells submodule of silicon based cells, a front transparent plate and a backsheet. The backsheet is arranged with at least a first conductive pattern that is connected to rear surface electrical contacts on each of the silicon cells. A thin film photovoltaic submodule is arranged between the front transparent plate and the silicon cells, and includes thin film cells in an arrangement with two photovoltaic submodule contacts that connect to a second conductive pattern on the backsheet. The backsheet is arranged for four-terminal wiring with the first pattern for the silicon cells and the second pattern for the thin film cells. The thin film cells are disposed in a first group of cells and in at least a second group of cells, each connected in series. The first group is connected in parallel with the second group, between the photovoltaic submodule contacts.

A method for manufacturing a heterojunction structure based solar cell includes preparing an n-type or p-type semiconductor substrate; forming a p-type or n-type non-oxide semiconductor material layer on the n-type or p-type semiconductor substrate to form a p-n junction; forming a transition metal oxide film on the non-oxide semiconductor material layer; and forming a front electrode and a rear electrode. The transition metal oxide layer protects the surface of the non-oxide semiconductor and improves charge extraction.