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.

A photovoltaic device that includes an upper cell that absorbs a first range of wavelengths of light and a bottom cell that absorbs a second range of wavelengths of light. The bottom cell includes a heterojunction comprising a crystalline germanium containing (Ge) layer. At least one surface of the crystalline germanium (Ge) containing layer is in contact with a silicon (Si) containing layer having a larger band gap than the crystalline (Ge) containing layer.

A photovoltaic device that includes an upper cell that absorbs a first range of wavelengths of light and a bottom cell that absorbs a second range of wavelengths of light. The bottom cell includes a heterojunction comprising a crystalline germanium containing (Ge) layer. At least one surface of the crystalline germanium (Ge) containing layer is in contact with a silicon (Si) containing layer having a larger band gap than the crystalline (Ge) containing layer.

This disclosure relates to semiconductor devices and methods for fabricating semiconductor devices. Particularly, the disclosure relates to back-contact-only multijunction solar cells and the process flows for making such solar cells, including a wet etch process that removes semiconductor materials non-selectively without major differences in etch rates between heteroepitaxial III-V semiconductor layers.

An augmented reality system can include a waveguide having an edge surface that extends between opposing light-guiding surfaces. The waveguide can guide light toward the edge surface. The waveguide can include a reflectivity-reducing film, such as an absorptive film or a photovoltaic film, disposed on the edge surface. To form the reflectivity-reducing film, curable material can be disposed onto a dissolvable film. The curable material can be cured while disposed on the dissolvable film such that the cured material forms a reflectivity-reducing structure on the dissolvable film. The dissolvable film can be dissolved such that the reflectivity-reducing structure remains intact as a reflectivity-reducing film that can be adhered to the edge surface, such as with a primer layer. The edge surface can include nanostructures, sized smaller than half a wavelength of the guided light, that can reduce a reflectivity of the edge surface.

An augmented reality system can include a waveguide having an edge surface that extends between opposing light-guiding surfaces. The waveguide can guide light toward the edge surface. The waveguide can include a reflectivity-reducing film, such as an absorptive film or a photovoltaic film, disposed on the edge surface. To form the reflectivity-reducing film, curable material can be disposed onto a dissolvable film. The curable material can be cured while disposed on the dissolvable film such that the cured material forms a reflectivity-reducing structure on the dissolvable film. The dissolvable film can be dissolved such that the reflectivity-reducing structure remains intact as a reflectivity-reducing film that can be adhered to the edge surface, such as with a primer layer. The edge surface can include nanostructures, sized smaller than half a wavelength of the guided light, that can reduce a reflectivity of the edge surface.

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 or ultraviolet absorbing visibly transparent photoactive compounds, optical materials, and/or buffer materials.

A solar cell comprising a bulk germanium silicon growth substrate; a diffused photoactive junction in the germanium silicon substrate; and a sequence of subcells grown over the substrate, with the first grown subcell either being lattice matched or lattice mis-matched to the growth substrate.

A method is provided for converting optical energy to electrical energy in a spectrally adaptive manner. The method begins by directing optical energy into a first photovoltaic module that includes non-single crystalline semiconductor layers defining a junction such that a first spectral portion of the optical energy is converted into a first quantity of electrical energy. A second spectral portion of the optical energy unabsorbed by the first module is absorbed by a second photovoltaic module that includes non-single crystalline semiconductor layers defining a junction and converted into a second quantity of electrical energy. The first quantity of electrical energy is conducted from the first module to a first external electrical circuit along a first path. The second quantity of electrical energy is conducted from the second module to a second external electrical circuit along a second path that is in parallel with the first path.

A method is provided for converting optical energy to electrical energy in a spectrally adaptive manner. The method begins by directing optical energy into a first photovoltaic module that includes non-single crystalline semiconductor layers defining a junction such that a first spectral portion of the optical energy is converted into a first quantity of electrical energy. A second spectral portion of the optical energy unabsorbed by the first module is absorbed by a second photovoltaic module that includes non-single crystalline semiconductor layers defining a junction and converted into a second quantity of electrical energy. The first quantity of electrical energy is conducted from the first module to a first external electrical circuit along a first path. The second quantity of electrical energy is conducted from the second module to a second external electrical circuit along a second path that is in parallel with the first path.