Abstract: According to one embodiment, a solar cell includes a first electrode, a second electrode, and a photoelectric conversion layer disposed between the first electrode and the second electrode. In a case where a photoluminescence spectrum of the photoelectric conversion layer is measured at a temperature of 100 K or lower, a first maximum value (A) which is a maximum value of emission intensity in a wavelength range of more than 650 nm and 1000 nm or less is 100 times or less of a second maximum value (B) which is a maximum value of emission intensity in a wavelength range of 600 nm or more and 650 nm or less (A?100B).

Abstract: According to one embodiment, a multi-junction solar cell includes a first solar cell, a second solar cell, and an insulating layer. The first solar cell includes a first photoelectric conversion element. The second solar cell is connected in parallel with the first solar cell. The second solar cell includes multiple second photoelectric conversion elements connected in series. The insulating layer is provided between the first solar cell and the second solar cell. The second photoelectric conversion element includes a p-electrode and an n-electrode. The p-electrode is connected to a p+-region including a surface on a side opposite to a light incident surface. The n-electrode is connected to an n+-region including the surface on the side opposite to the light incident surface. The p-electrodes oppose each other or the n-electrodes oppose each other in a region where the multiple second photoelectric conversion elements are adjacent to each other.

Abstract: A multi-junction solar cell module of an embodiment includes: a first solar cell module disposed on a light incident side and including a plurality of first solar cells and a first connection wiring electrically connecting the plurality of the first solar cells; a second solar cell module including a plurality of second solar cells and a second connection wiring electrically connecting the plurality of the second solar cells; and an adhesive layer between the first solar cell module and the second solar cell module.

Abstract: According to one embodiment, a solar cell includes a first electrode, a second electrode, a light-absorbing layer, and a plurality of metal parts. The light-absorbing layer is interposed between the first electrode and the second electrode. The metal parts are present on a surface of the first electrode opposing the second electrode. A void is provided in at least a part between the metal parts.

Abstract: A solar cell of an embodiment includes a first electrode, a light absorption layer, an n-type layer, and a second electrode. The light absorption layer exists between the first electrode and the n-type layer. The n-type layer exists between the light absorption layer and the second electrode. The light absorption layer contains Cu2O. The n-type layer contains a sulfide.

Abstract: According to one embodiment, a solar cell system includes a first solar cell including a first terminal and a second terminal, a second solar cell including a third terminal and a fourth terminal, and a voltage converter including a fifth terminal and a sixth terminal. The third terminal is electrically connected to the first terminal. The fifth terminal is electrically connected to the fourth terminal. The voltage converter causes a second absolute value to be smaller than a first absolute value. The first absolute value is of a difference between a first potential difference and a second potential difference. The first potential difference is between the first and second terminals. The second potential difference is between the first and fourth terminals. The second absolute value is of a difference between the first and third potential differences. The third potential difference is between the first and sixth terminals.

Abstract: A solar cell of an embodiment includes a high-resistance oxide layer; a first electrode comprising line-patterned conductive members or mesh-patterned conductive members; a second electrode; and a light absorbing layer between the high-resistance oxide layer and the second electrode. The first electrode is disposed between the high-resistance oxide layer and the light absorbing layer.

Abstract: A solar cell of an embodiment includes: a substrate having a light transmitting property; a first electrode including a plurality of metal portions and having a light transmitting property; a light absorbing layer disposed on the first electrode and absorbing light; and a second electrode disposed on the light absorbing layer and having a light transmitting property.

Abstract: A multi-junction solar cell of an embodiment includes a first solar cell including a first photoelectric conversion device, a second solar cell including a plurality of second photoelectric conversion devices connected in series and having a back contact, and an insulating layer between the first solar cell and the second solar cell. A device isolation region is provided between the second photoelectric conversion devices connected in series.

Abstract: A photoelectric conversion device of an embodiment has a substrate, a bottom electrode on the substrate, a light absorbing layer on the bottom electrode, an n-type layer on the light absorbing layer, a transparent electrode on the n-type layer, and an oxide layer on the transparent electrode. nA and nB satisfy the relation 100/110?nB/nA?110/100. nA is the refractive index of the transparent electrode. nB is the refractive index of the oxide layer.

Abstract: A photoelectric conversion device of an embodiment has a substrate, a bottom electrode comprising an electrode layer on the substrate and an intermediate interface layer, a light absorbing layer on the intermediate interface layer. The electrode layer comprises Mo or W. The intermediate interface layer is a compound thin film of a compound comprising Mo or W and at least one element X selected from the group consisting of S, Se, and Te. The intermediate interface layer has a crystal phase and an amorphous phase with which the crystal phase is covered.

Abstract: A solar module of an embodiment includes: a first solar panel having a plurality of first submodules each including a plurality of first solar cells; and a second solar panel layered with the first solar panel, the second solar panel having a plurality of second submodules each including a plurality of second solar cells. The first solar panel is provided on a side where light is incident. The first solar panel and the second solar panel are electrically connected in parallel. The plurality of first solar cells included in each of the plurality of first submodules is electrically connected in series. The plurality of first submodules is electrically connected in parallel. The plurality of second solar cells included in each of the plurality of second submodules is electrically connected in series. The plurality of second submodules is electrically connected in parallel.

Abstract: A photoelectric conversion element of an embodiment includes a first electrode, a second electrode, a light-absorbing layer having a compound containing group I-III-VI elements between the first electrode and the second electrode, and an n-type layer between the light-absorbing layer and the second electrode. A group IV element is contained in the light-absorbing layer closer to the n-type layer. A maximum peak of the concentration of group IV element exists in a region down to a depth of 0.2 ?m from a main surface of the light-absorbing layer facing to the n-type layer toward the first electrode.

Abstract: A solar cell of an embodiment includes: a first electrode; a second electrode; a light-absorbing layer interposed between the first electrode and the second electrode; a dot region interposed between the first electrode and the light-absorbing layer, the dot region including dots.

Abstract: A solar cell module of an embodiment includes: a first solar panel having a plurality of first submodules each including a plurality of first solar cells; and a second solar panel layered with the first solar panel, the second solar panel having a plurality of second solar cells. The first solar panel exists on the side where light is incident. The first solar panel and the second solar panel are electrically connected in parallel. The first solar cells included in the first submodules are electrically connected in series. The first submodules are electrically connected in parallel.

Abstract: A photoelectric conversion element of an embodiment includes a first electrode, a second electrode, and a light absorbing layer, containing a chalcopyrite-type compound containing at least a group-Ib element, a group-IIIb element, and a group-VIb element, between the first electrode and the second electrode. The group-VIb element includes at least sulfur. An average sulfur atom concentration S1 in a side surface region of the light absorbing layer is higher than an average sulfur atom concentration S2 in an inside region of the light absorbing layer.

Abstract: A solar cell of an embodiment has a first solar cell, a second solar cell, and an intermediate layer between the first and second solar cells. The first solar cell has a Si layer as a light absorbing layer. The second solar cell has as a light absorbing layer one of a group I-III-VI2 compound layer and a group I2-II-IV-VI4 compound layer. The intermediate layer has an n+-type Si sublayer and at least one selected from a p+-type Si sublayer, a metal compound sublayer, and a graphene sublayer. The metal compound sublayer is represented by MX where M denotes at least one type of element selected from Nb, Mo, Pd, Ta, W, and Pt and X denotes at least one type of element selected from S, Se, and Te.

Abstract: A photoelectric conversion element of an embodiment includes: a back electrode; a heterojunction-type light absorbing layer on the back electrode, containing Cu, selected from Al, In and Ga, and selected from Se and S, and having a chalcopyrite structure; a transparent electrode on the light absorbing layer, wherein aback electrode side-part of the light absorbing layer is of p-type, and a transparent electrode-side part of the light absorbing layer is of n-type, the light absorbing layer has a part with an average crystal grain size of 1,000 nm to 3,000 nm in the vicinity of the back electrode, and the light absorbing layer has apart with an average crystal grain size of at most 500 nm in the vicinity of the transparent electrode or the light absorbing layer has an amorphous part in the vicinity of the transparent electrode.

Abstract: A photoelectric conversion element of an embodiment includes a substrate, a transparent first electrode on the substrate, a second electrode, and a light absorbing layer of a homo-junction type interposed between the first electrode and the second electrode. The light absorbing layer includes a p-type region on the second electrode side and an n-type region on the first electrode side. The n-type region has an n-type dopant. The photoelectric conversion element has a boundary surface between the light absorbing layer on the n-type region side and the first electrode.

Abstract: A photoelectric conversion element of an embodiment includes a first electrode, a second electrode, and a light-absorbing layer containing a chalcopyrite-type compound containing a group Ib element, a group IIIb element, and a group VIb element between the first electrode and the second electrode. A region in which concentration of the group Ib element in the light-absorbing layer is from 0.1 to 10 atom %, both inclusive, is included in a region up to a depth of 10 nm in a direction from a principal plane of the light-absorbing layer on a side of the second electrode to a side of the first electrode.