An energy conversion device comprises at least two thin film photovoltaic cells fabricated separately and joined by wafer bonding. The cells are arranged in a hierarchical stack of decreasing order of their energy bandgap from top to bottom. Each of the thin film cells has a thickness in the range from about 0.5 m to about 10 m. The photovoltaic cell stack is mounted upon a thick substrate composed of a material selected from silicon, glass, quartz, silica, alumina, ceramic, metal, graphite, and plastic. Each of the interfaces between the cells comprises a structure selected from a tunnel junction, a heterojunction, a transparent conducting oxide, and an alloying metal grid; and the top surface and/or the lower surface of the energy conversion device may contain light-trapping means.

According to some aspects, an apparatus for converting electromagnetic radiation into electric power is provided, comprising a first layer comprising a first semiconductor material, an absorber in contact with the first layer, a second layer comprising a second semiconductor material, the second layer being in contact with the absorber, and a reflector to reflect at least a portion of electromagnetic radiation passing through the second layer. According to some aspects, a method of forming an apparatus for converting electromagnetic radiation into electric power is provided, comprising forming a reflector on a substrate, forming a first layer in contact with the reflector, the first layer comprising a first semiconductor material, forming an absorber in contact with the first layer, and forming a second layer in contact with the absorber, the second layer comprising a second semiconductor material.

The disclosure describes multi-junction solar cell structures that include two or more graded interlayers.

A photovoltaic device comprises at least two sub-cells, at least one connecting element electrically connecting adjacent sub-cells to one another, each sub-cell comprising: at least one segment; and at least one connecting element electrically connecting adjacent segments to one another in the event that a sub-cell has more than one segment; each one of the sub-cells having a unique bandgap and being arranged such that bandgaps of the sub-cells are in descending order with respect to a light incident surface of the photovoltaic device, each sub-cell being designed such that all segments of the photovoltaic device produce approximately the same current.

A semifinished product of a multi-junction solar cell includes a first semiconductor body that is designed as a first partial solar cell and has a first band gap, a second semiconductor body that is designed as a second partial solar cell and has a second band gap. The first semiconductor body and the second semiconductor body form a bonded connection to a tunnel diode and the first band gap is different from the second band gap. A first substrate material is adapted as a substrate layer, wherein a sacrificial layer is formed between the first substrate material and the first partial solar cell and the first substrate material is removed from the first semiconductor body, the sacrificial layer being destroyed in the process.

Methods for forming passivated contacts include implanting compound-forming ions into a substrate to about a first depth below a surface of the substrate, and implanting dopant ions into the substrate to about a second depth below the surface. The second depth may be shallower than the first depth. The methods also include annealing the substrate.

A multijunction solar cell assembly of two or more spatially split solar cell subassemblies, each of which includes a respective monolithic semiconductor body composed of a tandem stack of solar subcells, where the subassemblies are interconnected electrically to one another so that a series electrical circuit is formed between groups of one or more subcells in each subassembly. In some cases, relatively high band gap semiconductor materials can be used for the upper subcells. The solar cell assemblies can be particularly advantageous for applications in space.

A photoelectric conversion device including a transparent substrate, a first electrode, at least a photoelectric conversion layer and a second electrode is provided. The first electrode is located on the transparent substrate. The transparent substrate means that at least some parts of the substrate area are transparent. At least a photoelectric conversion layer is located on the first electrode, wherein the optical light transmittance of the photoelectric conversion layer in at least a portion of the visible spectrum is higher than 20%. The second electrode is located on the photoelectric conversion layer.

A semiconductor device is disclosed, and includes a first sub-cell generating a first electrical current, a second sub-cell generating a second electrical current, and at least one power converter. The first sub-cell and the second sub-cell are electrically coupled to one another in series. The power converter is electrically coupled to both the first sub-cell and the second sub-cell. The power converter introduces a compensating current into at least one of the first sub-cell and the second sub-cell to balance the first electrical current and the second electrical current to be substantially equal to one another.

A thickness of material may be detached from a substrate along a cleave plane, utilizing a cleaving process controlled by a releasable constraint plate. In some embodiments this constraint plate may comprise a plate that can couple side forces (the P-plate) and a thin, softer compliant layer (the S-layer) situated between the P-plate and the substrate. In certain embodiments a porous surface within the releasable constraint plate and in contact to the substrate, allows the constraint plate to be secured to the substrate via a first pressure differential. Application of a combination of a second pressure differential within a pre-existing cleaved portion, and a linear force to a side of the releasable constraint plate bound to the substrate, generates loading that results in controlled cleaving along the cleave plane.