A flip-chip multi junction solar cell chip integrated with a bypass diode includes from up to bottom: a glass cover; a transparent bonding layer; a front electrode; an n/p photoelectric conversion layer; a p/n tunnel junction; a structure layer of the n/p bypass diode; a first backside electrode; a second backside electrode. The solar cell chip also includes at least a through hole extending through the n/p photoelectric conversion layer, the p/n tunnel junction and the structure layer of the n/p bypass diode. An ultra-thin substrate-less cell can therefore be provided without occupying effective light receiving areas, greatly improving cell heat dissipation. With a light weight, the chip can also have advantages in space power application.

Visibly transparent photovoltaic devices are disclosed, such as those are transparent to visible light but absorb near-infrared light and/or ultraviolet light. The photovoltaic devices make use of transparent electrodes and near-infrared absorbing visibly transparent photoactive compounds, optical materials, and/or buffer materials.

Nanostructure array optoelectronic devices are disclosed. The optoelectronic device may have one or more intermediate electrical contacts that are physically and electrically connected to sidewalls of the array of nanostructures. The contacts may allow different photo-active regions of the optoelectronic device to be independently controlled. For example, one color light may be emitted or detected independently of another using the same group of one or more nanostructures. The optoelectronic device may be a pixilated device that may serve as an LED display or imaging sensor. The pixilated device may have an array of nanostructures with alternating rows and columns of sidewall electrical contacts at different layers. A pixel may be formed at the intersection of a row contact and a column contact. As one example, a single group of one or more nanostructures has a blue sub-pixel, a green sub-pixel, and a red sub-pixel.

Nanostructure array optoelectronic devices are disclosed. The optoelectronic device may have one or more intermediate electrical contacts that are physically and electrically connected to sidewalls of the array of nanostructures. The contacts may allow different photo-active regions of the optoelectronic device to be independently controlled. For example, one color light may be emitted or detected independently of another using the same group of one or more nanostructures. The optoelectronic device may be a pixilated device that may serve as an LED display or imaging sensor. The pixilated device may have an array of nanostructures with alternating rows and columns of sidewall electrical contacts at different layers. A pixel may be formed at the intersection of a row contact and a column contact. As one example, a single group of one or more nanostructures has a blue sub-pixel, a green sub-pixel, and a red sub-pixel.

A method of fabricating a four junction solar cell by identifying the composition and band gaps of the upper first, second and third subcells that maximizes the efficiency of the solar cell at a predetermined time after initial deployment by simulation; fabricating one or more four-junction test solar cells in accordance with the identified composition and band gaps of the upper first, second and third subcells; performing one or more optical or electrical tests on the fabricated one or more four-junction test solar cells; based on results of the tests, determining one or more properties of at least one of the upper first, second or third subcells to be modified in subsequent fabrication of four-junction solar cells, including the band gap, doping level and profile, and thickness of each of the subcell layers; and fabricating a further four-junction solar cell in accordance with the modified properties of at least one of the upper first, second or third subcells to optimize the efficiency of the solar cell at the predetermined time.

A method for passing photovoltaic current between a subcell formed from a single crystal Group ll-VI semiconductor material and a subcell formed from a single crystal Group IV semiconductor material, includes the steps of forming a first subcell by an epitaxial growth process, the first subcell having a first upper surface; forming a tunnel heterojunction between the first subcell and the second subcell, and tunneling carriers formed by light incident on the first and second subcells through the tunnel heterojunction, thereby permitting a photoelectric series current to flow through the first and second subcells.

A method for passing photovoltaic current between a subcell formed from a single crystal Group ll-VI semiconductor material and a subcell formed from a single crystal Group IV semiconductor material, includes the steps of forming a first subcell by an epitaxial growth process, the first subcell having a first upper surface; forming a tunnel heterojunction between the first subcell and the second subcell, and tunneling carriers formed by light incident on the first and second subcells through the tunnel heterojunction, thereby permitting a photoelectric series current to flow through the first and second subcells.

The present disclosure provides a fuel production method and a fuel production apparatus which efficiently convert solar light energy into a fuel. The fuel production apparatus of the present disclosure includes a laminate, an electrolytic bath, and a support tool or a proton permeable membrane. The laminate includes a photoelectromotive layer having a p-n junction structure, a cathode electrode, an anode electrode and a side surface insulating layer, and the photoelectromotive layer includes a semiconductor layer that absorbs light in a near-infrared region with a wavelength of 900 nm or more. In the fuel production apparatus, an underwater optical path length is set to an optimum design value, so that even light in a near-infrared region with a wavelength of 900 nm or more is sufficiently utilized to efficiently convert light energy into at least one fuel selected from hydrogen, carbon monoxide, formic acid, methane, ethylene, methanol, ethanol, isopropanol, allyl alcohol, acetaldehyde and propionaldehyde through a reduction reaction on the cathode electrode.

Lateral multi junction photovoltaic cells, devices, and methods of fabrication are provided. The photovoltaic cells include a plurality of photovoltaic subcells mechanically stacked together in a stack. Each photovoltaic subcell includes a subcell substrate, and a light absorption structure associated with the substrate. Each light absorption structure is optimized for a respective defined spectral range of incoming radiation, with the light absorption structures of multiple subcells of the plurality of photovoltaic subcells being optimized for different spectral ranges, and being offset in the stack relative to an optical axis to avoid overlap. The photovoltaic cell further includes a spectrally-dispersive optical element, with the photovoltaic subcells in the stack being respectively located and aligned relative to the optical element based, at least in part, on the respective spectral ranges of the subcells' light absorption structures.

A multijunction solar cell including interconnected first and second discrete semiconductor regions disposed adjacent and parallel to each other including first top solar subcell, second (and possibly third) lattice matched middle solar subcells; a graded interlayer adjacent to the last middle solar subcell; and a bottom solar subcell adjacent to said graded interlayer being lattice mismatched with respect to the last middle solar subcell; wherein an opening is provided from the bottom side of the semiconductor substrate to one or more of the solar subcells so as to allow a discrete electrical connector to be made extending in free space and to electrically connect contact pads on one or more of the solar subcells.