NOVELTY - Chalcopyrite solar cell (10) comprises a substrate (1), a photovoltaic layer structure (4) and an intermediate dielectric barrier layer (2) on the basis of polysilazane.    USE - Used as chalcopyrite solar cell. The polysilazane solution is useful for the production of barrier layers for chalcopyrite thin film solar cells of the type copper-indium-sulfide or copper-indium-gallium-selenide (claimed).    ADVANTAGE - The chalcopyrite solar cells can be cost-effectively produced with high diffusion barrier effect without defects such as holes and cracks.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for producing the chalcopyrite solar cell comprising (a) coating a substrate, which comprises metal, metal alloys, glass, ceramic or plastic with a solution containing at least one polysilazane having a structure of formula ((SiR1R2-NR3)n) (I), where the polysilazane exhibits a number average molecular weight of 150-150000 (preferably 100000-150000) g/mole, (b) removing the solvent by evaporation, where the polysilazane layer exhibits a thickness of 100-3000 (preferably 300-2000) nm obtained on the substrate, (d) curing the polysilazane layer by heating at 20-1000 degrees C, preferably 80-200 degrees C and/or irradiating with UV light having a wavelength of 180-230 nm, where the heating and/or radiation is carried out for 1 minute to 14 hours, preferably 1-30 minutes in an atmosphere of water vapor-containing air or nitrogen, and (e) optionally post-curing the polysilazane at 20-1000 degrees C, preferably 60-130 degrees C in air with a relative humidity of 60 to 90% over a period of 1 minute to 2 hours, preferably 30 minutes to 1 hour.    R1-R3 = H or optionally substituted alkyl, aryl, vinyl or (trialkoxysilyl)alkyl; and    n = an integer.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of a section of a chalcopyrite solar cell.    Substrate (1)    Intermediate dielectric barrier layer (2)    Photovoltaic layer structure (4)    Encapsulation layer (5)    Chalcopyrite solar cell (10)    Sodium or sodium-containing precursor layer (21)    Back contact (41)    Absorber (42)    Buffer (43)    Window layer. (44)