The present invention relates to a solar cell having nanostructures on both surfaces of a transparent substrate, and to a method for manufacturing same. The nano-structures, which face each other with respect to the substrate and which transport electrons, are formed using zinc-oxide nanowires. Also, a hole-transport layer using CIS nanoparticles is formed in order to absorb light having a short wavelength and to transport generated holes. A hole-transport layer including CIGS nanoparticles for absorbing light having a relatively long wavelength is formed on the side facing the hole-transport layer including the CIS nanoparticles.

Disclosed is a method of forming a CIGS-based thin film having high efficiency using a simple process at relatively low temperatures. The method includes an Ag thin film forming step and an ACIGS forming step of depositing Cu, In, Ga, and Se on the surface of the Ag thin film using a vacuum co-evaporation process. Ag, constituting the Ag thin film, is completely diffused, while Cu, In, Ga, and Se are deposited to form ACIGS together with Cu, In, Ga, and Se co-evaporated in a vacuum during the ACIGS forming step. The Ag thin film is formed and CIGS elements are then deposited using vacuum co-evaporation to form an ACIGS thin film having improved power generation efficiency at a relatively low temperature of 400 C. or less using only a single-stage vacuum co-evaporation process.

Improved methods and apparatus for forming thin film layers of chalcogenide on a substrate web. According to the present teachings, a feedback control system may be employed to measure one or more properties of the web and/or the chalcogenide layer, and to adjust one or more parameters of the system or buffer layer deposition method in response to the measurement.

A method for producing a P-N junction in a thin film photovoltaic cell comprising a deposition step in which are carried out successively: a layer of precursors of a photovoltaic material of type P or N, a barrier layer and a layer of precursors of a semiconducting material of type N or P, this deposition step being followed by an annealing step carried out with a supply of S and/or Se, this annealing step leading to the formation of an absorbing layer of the type P or N and of a buffer layer of type N or P and of a P-N junction at the interface between said layers.

Disclosed are a solar cell and a method of fabricating the solar cell. The solar cell includes a back electrode layer; a light absorbing layer on the back electrode layer; and a buffer layer on the light absorbing layer, wherein the buffer layer includes a first buffer layer, a second buffer layer on the first buffer layer and a third buffer layer on the second buffer layer, and wherein the first buffer layer includes a group I-VI compound. A method of fabricating a solar cell includes the steps of: forming a back electrode layer on a substrate; forming a light absorbing layer on the back electrode layer; forming a second buffer layer on the light absorbing layer including selenium; and forming a third buffer layer including sulfide on the second buffer layer.

Thin-film photovoltaic devices and methods of their use and manufacture are disclosed. More particularly, polycrystalline CuIn.sub.(1-x)Ga.sub.xSe.sub.2 (CIGS) based thin-film photovoltaic devices having independently tunable sublayers are disclosed. Also provided are methods of producing an n-doped graphene.

Provided are a water decomposition apparatus and a water decomposition method that can maintain high gas generation efficiency even in an early stage of light irradiation and even in a case where time has elapsed and that can recover the gas generation amount of hydrogen gas or the like, can generate hydrogen gas or the like stably for a long time on an average, and can increase the integrated amount of generation of hydrogen for a long time, even in a case where time has elapsed and the gas generation amount of hydrogen gas or the like has decreased.

A solar cell includes a metal layer and a chalcopyrite compound semiconductor layer in this order on a polyimide film. A manufacturing method according to the present invention includes the following steps in the order: cast applying a polyimide precursor solution onto a support base containing an alkali metal; imidizing the polyimide precursor by heating to form a stacked body including a polyimide film on the support base; forming a metal layer on the polyimide film of the stacked body; and forming a chalcopyrite compound semiconductor layer on the metal layer.

Disclosed is a photovoltaic device comprising a substrate composed of an oriented polycrystalline zinc oxide sintered body in a plate shape, a photovoltaic layer provided on the substrate, and an electrode provided on the photovoltaic layer. According to the present invention, a photovoltaic device having high photoelectric conversion efficiency can be inexpensively provided.

Monolithic tandem chalcopyrite-perovskite photovoltaic devices and techniques for formation thereof are provided. In one aspect, a tandem photovoltaic device is provided. The tandem photovoltaic device includes a substrate; a bottom solar cell on the substrate, the bottom solar cell having a first absorber layer that includes a chalcopyrite material; and a top solar cell monolithically integrated with the bottom solar cell, the top solar cell having a second absorber layer that includes a perovskite material. A monolithic tandem photovoltaic device and method of formation thereof are also provided.