NOVELTY - A photoelectric conversion element comprises: structure in which electrolyte layer (7) composed of porous film containing electrolyte solution is provided between porous photoelectrode (3) and counter electrode (6).    USE - As photoelectric conversion element, in the form of dye-sensitized photoelectric conversion element, useful for forming electronic apparatus (claimed). The photoelectric conversion element is dye-sensitized solar cell, or photosensor, for use as power supply in electronic apparatuses. The electronic apparatuses include both portable and stationary apparatuses e.g. portable phones, mobile apparatuses, robots, personal computers, on-vehicle apparatuses, and various home electronics.    ADVANTAGE - The photoelectric conversion element such as dye-sensitized solar cell prevents leakage of electrolyte solution from occurring upon breakage of the element, due to presence of solid state electrolyte layer having porous film. In addition, incident light transmitted through porous photoelectrode to enter element is scattered by porous film constituting electrolyte layer, to be again incident on porous photoelectrode, so that efficiency of trapping incident light by porous photoelectrode is enhanced. This makes it possible to realize photoelectric conversion element which is high in short-circuit current density and photoelectric conversion efficiency. Since electrolyte layer can be formed by use of porous film containing electrolyte solution, electrolyte solution can substantially be handled as film, so that electrolyte solution can be handled extremely easily, and also can be manufactured easily. It is further found that better properties than those obtained by use of 4-tert-butylpyridine can be obtained by use of additive which has pKa of 6.04-7.3. This makes it possible to obtain photoelectric conversion element in which choice of additives to electrolyte solution is broad and better characteristics can be obtained. Further, use of specific combination of ionic liquid and organic solvent results in dye-sensitized solar cell in which volatilization of electrolyte solution can be restrained and excellent photoelectric conversion characteristics can be obtained, due to lowering in viscosity coefficient of electrolyte solution. In ionic liquid having electron-acceptive functional group and organic solvent having electron-donative functional group; molecule of ionic liquid and molecule of organic solvent are coupled together through hydrogen bond, which restrains volatilization of organic liquid, and of electrolyte solution, as compared with case where organic solvent is used by itself. Besides, since solvent of electrolyte solution contains organic solvent in addition to ionic liquid, viscosity coefficient of electrolyte solution can be lowered and deterioration of photoelectric conversion characteristics can be prevented, as compared with case where only ionic liquid is used as solvent. The photoelectric conversion element thus results in high-performance electronic apparatus.    DETAILED DESCRIPTION - A photoelectric conversion element comprises: structure in which electrolyte layer (7) composed of porous film containing electrolyte solution is provided between porous photoelectrode (3) and counter electrode (6). The porous film has non-woven fabric. The porous film has porosity of 80% to less than 100%. An additive having pKa of 6.04-7.3 is added to electrolyte solution and/or additive having pKa of 6.04-7.3 is adsorbed on surface of at least one of porous photoelectrode and counter electrode which faces electrolyte layer. The electrolyte is ionic liquid electrolyte solution. The solvent of electrolyte solution has molecular weight of not less than 47.3. The solvent of electrolyte solution contains ionic liquid having electron-acceptive functional group, and organic solvent having electron-donative functional group. The porous photoelectrode is composed of particulates having semiconductor. The porous photoelectrode is composed of particulates each of which includes core having metal and shell having metallic oxide surrounding core. INDEPENDENT CLAIMS are included for the following:    (1) manufacturing photoelectric conversion element, involving: disposing porous film on one of porous photoelectrode and counter electrode; and disposing other of porous photoelectrode and counter electrode on porous film;    (2) electrolyte layer for photoelectric conversion element, comprising: porous film containing electrolyte solution; and    (3) electronic apparatus comprising: at least photoelectric conversion element, having structure in which electrolyte layer having porous film containing electrolyte solution is provided between porous photoelectrode and counter electrode.    DESCRIPTION OF DRAWING(S) - The figure shows sectional of the dye-sensitized photoelectric conversion element.    Transparent substrate (1)    Transparent electrode (2)    Porous photoelectrode (3)    Counter substrate (4)    Conductive layer (5)    Counter electrode (6)    Electrolyte layer having porous film containing electrolyte solution (7)    Sealing material (8)