NOVELTY - The photovoltaic hybrid electrolytic cell comprises an anode and a cathode, where the cathode is formed as photocathode (04) provided with a semiconductor layer structure for light incidence at a front side of the photo cathode and for supporting an electrically conductive, opaque back contact layer, and the anode and the photocathode are electrically connected to each other. The anode is placed in an anode electrolyte chamber (10) with aqueous electrolytes and an oxygen catalyst. The photocathode is placed in a cathode electrolyte chamber with aqueous electrolytes and a hydrogen catalyst.    USE - The photovoltaic hybrid electrolysis cell is useful for direct light-induced decomposition of water to generate hydrogen at a decomposition voltage of 1.23 V (claimed).    ADVANTAGE - The photovoltaic hybrid electrolysis cell allows direct light-induced decomposition of the water in an energy efficient manner.    DETAILED DESCRIPTION - The photovoltaic hybrid electrolytic cell comprises an anode and a cathode, where the cathode is formed as photocathode (04) provided with a semiconductor layer structure for light incidence at a front side of the photocathode and for supporting an electrically conductive, opaque back contact layer, and the anode and the photocathode are electrically connected to each other. The anode is placed in an anode electrolyte chamber (10) with aqueous electrolytes and an oxygen catalyst, and the photocathode is placed in a cathode electrolyte chamber with the aqueous electrolytes and a hydrogen catalyst. The anode and cathode electrolyte chambers are separated from each other by a proton-conducting membrane and a transparent glass wall through which the light passes for operation. The glass wall is formed as a superstrate (14) having a top and a bottom, where the top is provided for light incident, and the bottom is covered with a transparent electrically conductive conducting layer (12) and is connected to the front side of the photocathode. The back contact layer of the photocathode comprises a corrosion-resistant material and a hydrogen barrier layer disposed on a hydrogen-catalyst layer. The hydrogen-catalyst layer is connected to the cathode electrolyte chamber. The photocathode is electrically insulated from the proton-conducting membrane. The anode is formed as a photoanode (03) provided with a semiconductor layer structure for incidence of light at a front side of the photoanode and for supporting an electrically conductive, opaque back contact layer, and is disposed adjacent to the photocathode. The front side of photoanode on the conductive layer is connected to the bottom of the superstrate. The back contact layer of the photoanode includes a corrosion resistant material and an oxygen catalyst, or is applied as an oxygen catalyst layer. The back contact layer of the photo anode or oxygen-catalyst layer is connected to the anode electrolytic chamber. The photo anode is electrically insulated from the proton-conducting membrane. The photocathode and photoanode are electrically connected to each other via the electrically conductive conducting layer. The anode is further formed as a dark anode. A front side of the dark anode is connected to an electrically conductive conducting layer disposed on a substrate. The conducting layer includes oxygen catalyst, or is applied as the oxygen catalyst layer. The anode and cathode electrolyte chambers are further separated by an electrically insulating, corrosion-resistant partition wall. The conductive layer on the substrate and additional electrolyte chamber is electrically conductively connected to the conductive layer on the superstrate. The hydrogen and oxygen catalyst layer of the photoanode and photocathode has a nanoporous surface, and a maximum operating point of the hybrid electrolysis cell is adjustable. The anode and cathode electrolyte chambers are provided to cool the photovoltaic hybrid electrolytic cell. A housing is provided with corrosion-resistant walls, narrow walls and a corrosion-resistant base, and provided at a top of the superstrate. The dark anode and the photocathode are electrically conductively connected to each other via an electrically conductive connection, and are electrically insulated relative to the walls. The conducting layers include conducting oxides and conductive polymer. The superstrate and substrate includes glass, coated glass, plastic and/or corrosion resistant plastic.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic lateral view of a photovoltaic hybrid electrolysis cell.    Photo anode (03)    Photo cathode (04)    Anode electrolyte chamber (10)    Conductive layer (12)    Superstrate. (14)