A bipolar solar cell includes a backside junction formed by an N-type silicon substrate and a P-type polysilicon emitter formed on the backside of the solar cell. An antireflection layer may be formed on a textured front surface of the silicon substrate. A negative polarity metal contact on the front side of the solar cell makes an electrical connection to the substrate, while a positive polarity metal contact on the backside of the solar cell makes an electrical connection to the polysilicon emitter. An external electrical circuit may be connected to the negative and positive metal contacts to be powered by the solar cell. The positive polarity metal contact may form an infrared reflecting layer with an underlying dielectric layer for increased solar radiation collection.

Manufacture for an improved stacked-layered thin film solar cell. Solar cell has reduced absorber thickness and an improved back contact for Copper Indium Gallium Selenide solar cells. The back contact provides improved reflectance particularly for infrared wavelengths while still maintaining ohmic contact to the semiconductor absorber. This reflectance is achieved by producing a back contact having a highly reflecting metal separated from an absorbing layer with a dielectric layer.

In various embodiments, photovoltaic devices incorporate discontinuous passivation layers (i) disposed between a thin-film absorber layer and a partner layer, (ii) disposed between the partner layer and a front contact layer, and/or (iii) disposed between a back contact layer and the thin-film absorber layer.

A monolithic multiple solar cell includes at least three partial cells, with a semiconductor mirror placed between two partial cells. The aim of the invention is to improve the radiation stability of said solar cell. For this purpose, the semiconductor mirror has a high degree of reflection in at least one part of a spectral absorption area of the partial cell which is arranged above the semiconductor mirror and a high degree of transmission within the spectral absorption range of the partial cell arranged below the semiconductor mirror.

Photovoltaic devices including direct gap III-V absorber materials and operatively associated back structures enhance efficiency by enabling photon recycling. The back structures of the photovoltaic devices include wide bandgap III-V layers, highly doped (In)GaAs layers, patterned oxide layers and metal reflectors that directly contact the highly doped (In)GaAs layers through vias formed in the back structures. Localized ohmic contacts are formed in the back structures of the devices.

Manufacture of an improved stacked-layered thin film solar cell. The solar cell has reduced absorber thickness and an improved back contact for Copper Indium Gallium Selenide solar cells. The back contact provides improved reflectance particularly for infrared wavelengths while still maintaining ohmic contact to the semiconductor absorber. This reflectance is achieved by producing a back contact having a highly reflecting metal separated from an absorbing layer with a dielectric layer.

A monolithic multiple solar cell includes at least three partial cells, with a semiconductor mirror placed between two partial cells. The aim of the invention is to improve the radiation stability of said solar cell. For this purpose, the semiconductor mirror has a high degree of reflection in at least one part of a spectral absorption area of the partial cell which is arranged above the semiconductor mirror and a high degree of transmission within the spectral absorption range of the partial cell arranged below the semiconductor mirror.

A light trapping optical structure employing an optically transmissive layer with a plurality of light deflecting elements. The transparent layer is defined by opposing broad-area surfaces extending parallel to each other. The light deflecting elements deflect light propagating transversely through the optically transmissive layer at a sufficiently high bend angle with respect to a surface normal, above a critical angle of a Total Internal Reflection. The deflected light is retained by means of at least TIR in the system which allows for longer light propagation paths through a photoabsorptive layer that may be associated with the optically transmissive layer for an improved light absorption. The light trapping optical structure may further employ a focusing array of light collectors being pairwise associated with the respective light deflecting elements.

Methods of fabricating solar cells using a metal-containing thermal and diffusion barrier layer in foil-based metallization approaches, and the resulting solar cells, are described. For example, a method of fabricating a solar cell includes forming a plurality of semiconductor regions in or above a substrate. The method also includes forming a metal-containing thermal and diffusion barrier layer above the plurality of semiconductor regions. The method also includes forming a metal seed layer on the metal-containing thermal and diffusion barrier layer. The method also includes forming a metal conductor layer on the metal seed layer. The method also includes laser welding the metal conductor layer to the metal seed layer. The metal-containing thermal and diffusion barrier layer protects the plurality of semiconductor regions during the laser welding.

A thin film solar cell includes a protection layer, a substrate and a photovoltaic conversion structure having a stack of one or several of non-planar light absorption layers, a first conductive layer being light transmissive and a second conductive layer being at least partially transparent or totally reflective. When the second conductive layer is totally reflective, it reflects the sunlight to the adjacent part of the thin film solar cell, proceeding another photovoltaic conversion and generating electric power again. If the non-planar light absorption layer is sloped enough, there will be several photovoltaic conversions produced by the same incident sunlight. More power will be generated and the efficiency of conversion is increased. If the second conductive layer is at least partially transparent, the incident light will be reflected less. However, the structure will provide several opportunities of photovoltaic conversions for the light with larger incident angle.