A photonic bandgap structure having multiple stacked layers has a thickness from the top of its top layer to the bottom of its bottom layer of less than one micron. Metal conducting layers having negative real dielectric constants are positioned between semiconductor layers having positive dielectric constants. The layers are arranged and stacked, and the thicknesses and materials for the semiconductor layers and conductive layers are selected to realize desired absorption, transmission, and reflection characteristics.

An optoelectronic semiconductor device is disclosed. The optoelectronic device comprises a plurality of stacked p-n junctions. The optoelectronic semiconductor device includes a n-doped layer disposed below the p-doped layer to form a p-n layer such that electric energy is created when photons are absorbed by the p-n layer. Recesses are formed on top of the p-doped layer at the top of the plurality of stacked p-n junctions. The junctions create an offset and an interface layer is formed on top of the p-doped layer at the top of the plurality stacked p-n junctions. The optoelectronic semiconductor device also includes a window layer disposed below the plurality stacked p-n junctions. In another aspect, one or more optical filters are inserted into a multi-junction photovoltaic device to enhance its efficiency through photon recycling.

A film mirror having a metal reflective layer formed on a resin substrate may include, closer to a light incident side than the metal reflective layer, an interface reflective layer having at least one set of a high refractive index layer and a low refractive index layer that are adjacent to each other. At least one of the high refractive index layer and the low refractive index layer may include a water soluble polymer and metal oxide particles. A method for manufacturing the film mirror may include forming the interface reflective layer by simultaneous multilayer coating of materials of the high refractive index layer and the low refractive index layer.

A film mirror having a metal reflective layer formed on a resin substrate may include, closer to a light incident side than the metal reflective layer, an interface reflective layer having at least one set of a high refractive index layer and a low refractive index layer that are adjacent to each other. At least one of the high refractive index layer and the low refractive index layer may include a water soluble polymer and metal oxide particles. A method for manufacturing the film mirror may include forming the interface reflective layer by simultaneous multilayer coating of materials of the high refractive index layer and the low refractive index layer.

A method of manufacturing a solar cell comprising: providing a growth substrate depositing on the growth substrate an epitaxial sequence of layers of semiconductor material forming at least a first and second solar subcells depositing a semiconductor contact layer on top of the second solar subcell depositing a reflective metal layer over said semiconductor contact layer such that the reflectivity of the reflective metal layer is greater than 80% in the wavelength range 850 to 2000 nm depositing a contact metal layer composed on said reflective metal layer mounting and bonding a supporting substrate on top of the contact metal layer and removing the growth substrate.

A solar cell system and a flexible solar panel are disclosed herein. The solar cell system includes a glass housing, a set of rows of solar cells each defining a front side and a rear side and arranged within the glass housing. The solar cell system can also include a reflective element disposed in the glass housing and facing the rear side of the set of rows of solar cells and a first terminal coupled to a first end of the set of rows of solar cells, traversing through and sealed against the first end of the glass housing. The solar cell system can be configured with other solar cell systems into the flexible solar panel that is deployable in a wide range of potential applications.

A solar cell system and a flexible solar panel are disclosed herein. The solar cell system includes a glass housing, a set of rows of solar cells each defining a front side and a rear side and arranged within the glass housing. The solar cell system can also include a reflective element disposed in the glass housing and facing the rear side of the set of rows of solar cells and a first terminal coupled to a first end of the set of rows of solar cells, traversing through and sealed against the first end of the glass housing. The solar cell system can be configured with other solar cell systems into the flexible solar panel that is deployable in a wide range of potential applications.

The present invention relates to a method for preparing a porous polymer film having a controlled pore depth, and a porous polymer film prepared thereby. A method for preparing a porous polymer film according to the present invention allows the pore depth of a porous film to be controlled simply and at a low cost, and thus allows adjustment of the light reflectance of the prepared film. A large-area film can be prepared by means of a simple method and thus can be applied to various industry fields. Films having different reflectance can be prepared and thus can be applied as low-reflection and high-reflection films for solar cells, and also as a low-reflection or high-reflection thin polymer film in the construction field or material and equipment field.

A method is described that includes sputtering multiple layers on a back surface of the photovoltaic structure, the photovoltaic structure being made of at least one group III-V semiconductor material, and evaporating, over the multiple layers, one or more additional layers including a metal layer, the back metal structure being formed by the multiple layers and the additional layers. A photovoltaic device is also described that includes a back metal structure disposed over a back surface of a photovoltaic structure made of a group III-V semiconductor material, the back metal structure including one or more evaporated layers disposed over multiple sputtered layers, the one or more evaporated layers including a metal layer. By allowing evaporation along with sputtering, tool size and costs can be reduced, including minimizing a number of vacuum breaks. Moreover, good yield and reliability, such as reducing dark line defects (DLDs), can also be achieved.

A method is described that includes sputtering multiple layers on a back surface of the photovoltaic structure, the photovoltaic structure being made of at least one group III-V semiconductor material, and evaporating, over the multiple layers, one or more additional layers including a metal layer, the back metal structure being formed by the multiple layers and the additional layers. A photovoltaic device is also described that includes a back metal structure disposed over a back surface of a photovoltaic structure made of a group III-V semiconductor material, the back metal structure including one or more evaporated layers disposed over multiple sputtered layers, the one or more evaporated layers including a metal layer. By allowing evaporation along with sputtering, tool size and costs can be reduced, including minimizing a number of vacuum breaks. Moreover, good yield and reliability, such as reducing dark line defects (DLDs), can also be achieved.