NOVELTY - The method comprises depositing a metal-organic precursor solution (1) comprising and/or forming carboxylate chelate complexes on a substrate (4) to form a deposited precursor film, drying the precursor film using thermal treatment for forming a precursor layer (2) on the substrate in form of a solid, amorphous carbon-rich matrix comprising coordinated metal ions, and converting the precursor layer using thermal treatment in an atmosphere of a chalcogen for decomposition of the carbon-rich matrix, chalcogenization of metals and formation of a chalcogenide film (5).    USE - The method is useful for fabrication of a light absorbing chalcogenide film on a rigid or flexible substrate such as glass, metal, ceramic or polymer substrates, where the light absorbing chalcogenide film is useful for photovoltaic devices (all claimed).    ADVANTAGE - The method ensures economic and efficient fabrication of the light absorbing chalcogenide film with lightweight and high throughput and without the need of pre-fabricated nanoparticles or organometallic molecules thus improving the quantum efficiency of the reproducible and rapidly workable photovoltaic device, does not require addition of organic binder materials to adjust the solution rheology and the use of highly toxic and explosive materials.    DETAILED DESCRIPTION - The method comprises depositing a metal-organic precursor solution (1) comprising and/or forming carboxylate chelate complexes on a substrate (4) to form a deposited precursor film, drying the precursor film using thermal treatment for forming a precursor layer (2) on the substrate in form of a solid, amorphous carbon-rich matrix comprising coordinated metal ions, and converting the precursor layer using thermal treatment in an atmosphere of a chalcogen for decomposition of the carbon-rich matrix, chalcogenization of metals and formation of a chalcogenide film (5) with or without metal or oxide electrically conductive contact layer (3). The converting step is initially carried out by incomplete chalcogenization and incomplete decomposition of the carbon-rich matrix such that a carbon-rich layer (6) adjacent to the substrate is simultaneously formed with the chalcogenide film, where the carbon-rich layer has a functionality as an alternative back contact in photovoltaic devices. The metal-organic precursor solution comprises carboxylates including formates, acetates and/or oxalates, which form carboxylate chelate complexes, and metal salts and a polar solvent to provide anion species, which form carboxylate chelate complexes with coordinated metal ions. The metal salts contain an IB element, IIB element, IIIA element and/or IVA element of the periodic table. The solution contains VIA elements in its elemental form or as a compound. The deposited precursor film is dried at room temperature to 300 degrees C in inert or ambient atmosphere for 30 second to 10 min. The conversion step is performed at 350-800 degrees C during 1-60 min in a VIA element comprising atmosphere. The anions of utilized salts are nitrate, manganate, chromate, chlorate and/or hypochlorate for oxidizing the solvent into species suitable as ligands to form carboxylate chelate complexes with metal ions. The amount and thickness of the carbon-rich layer is controlled by addition of carbon containing material to the precursor solution. A thickness of the carbon-rich layer is 20 Mm. The decomposition of the carbon-rich matrix is accompanied by: simultaneously forming reducing species; preventing the formation of metal oxides; and leading to high phase purity of the obtained chalcogenide film. The reducing species are carbon monoxide.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a process for producing a chalcogenide absorber film.    Metal-organic precursor solution (1)    Precursor layer (2)    Electrically conductive contact layer (3)    Substrate (4)    Light absorbing chalcogenide thin film (5)    Carbon-rich layer. (6)