According to the present invention, a CuGa alloy sputtering target which is a sintered body has a composition with 29.5 atom % to 43.0 atom % of Ga and a balance of Cu and inevitable impurities. A CuGa alloy crystal particle in the sintered body has a structure in which phase particles are dispersed in a .sub.1-phase crystal particle. A method for producing the sputtering target includes a step of performing normal pressure sintering by heating a molded body formed of a powder mixture of a pure Cu powder and a CuGa alloy powder in a reducing atmosphere, and a step of cooling the obtained sintered body at a cooling rate of 0.1 C./min to 1.0 C./min, at a temperature having a range of 450 C. to 650 C.

A photoelectric conversion device includes an electrode layer, a first semiconductor layer located on a main surface of the electrode layer, a plurality of insulating light scattering substances scattered in the first semiconductor layer or scattered at an interface between the first semiconductor layer and the electrode layer, and a second semiconductor layer making a pn junction with the first semiconductor layer on the first semiconductor layer to be located on an opposite side of the electrode layer.

A method for forming a photovoltaic device includes forming a photovoltaic absorption stack on a substrate including one or more of I-III-VI.sub.2 and I.sub.2-II-IV-VI.sub.4 semiconductor material. A transparent conductive contact layer is deposited on the photovoltaic absorption stack at a temperature less than 200 degrees Celsius. The transparent conductive contact layer has a thickness of about one micron and is formed on a front light-receiving surface. The surface includes pyramidal structures due to an as deposited thickness. The transparent conductive contact layer is wet etched to further roughen the front light-receiving surface to reduce reflectance.

A method for forming a thin film having sulfide single-crystal nanoparticles includes dropping a sulfide precursor solution on the surface of a Group VI absorption layer, and then performing thermal decomposition on the sulfide precursor solution under a predetermined temperature to form a thin film consisting of sulfide single-crystal nanoparticles on the surface of the Group VI absorption layer.

Disclosed are a solar cell module and a method of fabricating the same. The solar cell module includes a back electrode layer disposed on a support substrate and having a first separation pattern, a light absorbing layer disposed on the back electrode layer and having a second separation pattern, and a plurality of solar cells disposed on the light absorbing layer and formed with a front electrode layer including an insulator.

A solar cell having an electrical modulating stack layer is provided. The solar cell includes a first electrode, a second electrode, a photoelectric conversion layer, disposed between the first electrode and the second electrode. A first electrical modulating stack layer is disposed on the first electrode, wherein the first electrical modulating stack layer includes at least one positively charged layer and at least one negatively charged layer or the first electrical modulating layer includes a first surface modification layer.

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.

A photovoltaic device (e.g., solar cell) includes: a front substrate (e.g., glass substrate); a semiconductor absorber film; a back contact including a first conductive layer of or including copper (Cu) and a second conductive layer of or including molybdenum (Mo); and a rear substrate (e.g., glass substrate). A selenium blocking layer is provided between at least the Cu inclusive layer and the Mo inclusive layer.

A solar cell apparatus according to the embodiment includes a support substrate; a back electrode layer on the support layer; a light absorbing layer on the back electrode layer; a plurality of buffer layers on the light absorbing layer, the plurality of buffer layers having a bandgap gradually increased from a bottom thereof to a top thereof; and a window layer on the buffer layers.

A 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.