Disclosed are a precursor for preparing a light absorption layer of a solar cell including (a) an aggregate-phase composite including a first phase including a copper (Cu)-tin (Sn) bimetallic metal and a second phase including zinc (Zn)-containing chalcogenide, or including the first phase including a copper (Cu)-tin (Sn) bimetallic metal, the second phase including zinc (Zn)-containing chalcogenide and a third phase including copper (Cu)-containing chalcogenide; or (b) core-shell structured nanoparticles including a core including copper (Cu)-tin (Sn) bimetallic metal nanoparticles and a shell including zinc (Zn)-containing chalcogenide, or the zinc (Zn)-containing chalcogenide and copper (Cu)-containing chalcogenide; or (c) a mixture thereof, and a method of preparing the same.

A method for manufacturing a CZTS based thin film having a dual band gap slope, comprising the steps of: forming a Cu.sub.2ZnSnS.sub.4 thin film layer; forming a Cu.sub.2ZnSn(S,Se).sub.4 thin film layer; and forming a Cu.sub.2ZnSnS.sub.4 thin film layer. A method for manufacturing a CZTS based solar cell having a dual band gap slope according to another aspect of the present invention comprises the steps of: forming a back contact; and forming a CZTS based thin film layer on the back contact by the method described above.

Methods of making a semiconductor layer from nanocrystals are disclosed. A film of nanocrystals capped with a ligand can be deposited onto a substrate; and the nanocrystals can be irradiated with one or more pulses of light. The pulsed light can be used to substantially remove the ligands from the nanocrystals and leave the nanocrystals unsintered or sintered, thereby providing a semiconductor layer. Layered structures comprising these semiconductor layers with an electrode are also disclosed. Devices comprising such layered structures are also disclosed.

Disclosed is a photovoltaic device that includes a solar cell on a light transmissive substrate in the form of an array of equal diameter optical fibers laid adjacent to each other in the transversal direction of the fibers. With such an arrangement, light harvesting at high angles is improved by 30%.

A method for forming a photovoltaic device includes forming an absorber layer with a granular structure on a conductive layer; conformally depositing an insulating protection layer over the absorber layer to fill in between grains of the absorber layer; and planarizing the protection layer and the absorber layer. A buffer layer is formed on the absorber layer, and a top transparent conductor layer is deposited over the buffer layer.

A direct solution method based on a versatile amine-thiol solvent mixture which dissolves elemental metals, metal salts, organometallic complexes, metal chalcogenides, and metal oxides is described. The metal containing and metal chalcogenide precursors can be prepared by dissolving single or multiple metal sources, chalcogens, and/or metal chalcogenide compounds separately, simultaneously, or stepwise. Multinary metal chalcogenides containing at least one of copper, zinc, tin, indium, gallium, cadmium, germanium, and lead, with at least one of sulfur, selenium, or both are obtained from the above-mentioned metal chalcogenide precursors in the form of thin films, nanoparticles, inks, etc. Furthermore, infiltration of metal containing compounds into a porous structure can be achieved using the amine-thiol based precursors. In addition, due to the appreciable solubility of metal sources, metal chalcogenides, and metal oxides in the mixture of amine(s) and thiol(s), this solvent mixture can be used to remove these materials from a system.

The present invention relates to a method for preparing an aqueous or hydro-alcoholic colloidal solution of metal chalcogenide amorphous nanoparticles notably of the Cu.sub.2ZnSnS.sub.4 (CZTS) type and to the obtained colloidal solution. The present invention also relates to a method for manufacturing a film of large-grain crystallized semi-conducting metal chalcogenide film notably of CZTS obtained from an aqueous or hydro-alcoholic colloidal solution according to the invention, said film being useful as an absorption layer deposited on a substrate applied in a solid photovoltaic device.

A method of fabricating a color tunable thin film photovoltaic device includes depositing a layer of a semiconducting compound configured to exhibit a photovoltaic effect, and depositing a buffer layer over the layer of the semiconducting compound. Depositing transparent conducting oxides (TCO) over the buffer layer is followed by selecting two or more layers of optically transparent materials such that constructive interference among wavelengths reflected by the buffer layer, the TCO, and the two or more layers results in a desired exhibited color and depositing the two or more layers of the optically transparent materials above the TCO.

In various embodiments, evaporation sources are heated and/or cooled via a fluid-based thermal management system during deposition of thin films.

A layer structure for a thin-film solar cell and production method are provided. The layer structure for the thin-film solar cell includes a photovoltaic absorber layer doped, at least in a region which borders a surface of the photovoltaic absorber layer, with at least one alkali metal. The layer structure has an oxidic passivating layer on the surface of the photovoltaic absorber layer, which is designed to protect the photovoltaic absorber layer from corrosion.