NOVELTY - Photovoltaic cells comprise a catalytic intermediate layer comprising a highly porous catalytically active conductive layer having metal catalyst particles and/or a support decorated with catalytically active metal compounds whereby the pores of the catalytic intermediate layer are at least partially filled with electrolyte which is a mixture of an ionic liquid and a redox system.    USE - The photovoltaic cell (I) is useful as a solar cell, solar panel or photo-electrochemical converter in the open or in buildings (claimed).    ADVANTAGE - The photovoltaic cell (I) has a higher current density and efficiency than conventional cells.    DETAILED DESCRIPTION - Photovoltaic cells (I) comprise:    (a) an at least partially transparent photoelectrode upon which a transparent electrically insulating material (1), a transparent conductive coating (2) and a porous layer (3) of nanocrystalline semiconductor material on which a radiation sensitive dyestuff is adsorbed;    (b) a counter electrode having a layer (8) of a conductive material with, between the electrodes, at least one porous electrically insulating intermediate layer (9) applied to the electrode (A) whereby the pores of the layers (3), (8) and (9) are at least partially filled with a conductive electrolyte and a catalytic intermediate layer (10) is situated between the intermediate layer (9) and the counter electrode (8) having a different composition to that of the counter electrode (8) and the intermediate layer (9) and comprises a highly porous catalytically active conductive layer having metal catalyst particles and/or a support decorated with catalytically active metal compounds and the pores of the catalytic intermediate layer (10) are at least partially filled with electrolyte which is a mixture of an ionic liquid and a redox system.    An INDEPENDENT CLAIM is included for a process for the production of the photovoltaic cells (I) by application of a transparent conductive layer (2) onto a transparent insulating material (1) and coating the layer (2) with a porous layer (3); application of a porous electrically insulating intermediate layer (9) onto the photoelectrode (A) followed by a catalytic intermediate layer (10), and a layer of a conductive porous material as counter electrode (B) followed by treatment with a liquid containing a radiation sensitive dyestuff and filling the layers (3), (8), (9) and (10) with electrolyte.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic cross-section view of a photovoltaic cell (I).    Glass (1)    Transparent conductive oxide (2)    Dyestuff (3)    Insulating layer (9)    Conductive graphite layer (8)    Catalyst layer (10)    Protective layer (11)