TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The resin is a polymer blend in which the polymeric materials (I) and (II) form a cross-linking structure. The polymeric material (I) and the polymer component (A) are polymers comprising a monomer containing a vinyl group. The polymeric material (II) contains a hydroxyl group. Both the polymeric components (A) and (B) contain a hydroxyl group. The polymeric component (B) is a polymer containing a polysiloxane group. The ratio of polymer component (A) in the polymeric material (II) is 10-90 weight parts. The polymer component (B) contains a monomer containing a siloxane group and a vinyl group, at a ratio of 1-1000. Preferred Properties: The refraction index of the polymer component (B) differs from that of component (A). EXAMPLE - An aluminum layer of 500 nm thickness and a zinc oxide layer of 500 nm thickness, were formed on a cleaned stainless steel substrate by sputtering method. Subsequently, an n-type silver layer from a mixed gas of silane, phosphine and hydrogen, an i-type silicon layer from a mixed gas of silane and hydrogen, and a p-type microcrystalline silicon layer from a mixed gas of silane, boron trifluoride and hydrogen, were formed by plasma CVD method to form a tandem-type silicon semiconductor photoactive layer. An indium oxide thin film was formed as a transparent conductive layer. Defects of the photovoltaic element were removed. By dipping the photovoltaic element and an electrode board so that the electrode board was facing the electroconductive layer of photovoltaic element, in aqueous solution of ammonium chloride adjusted so that electric conductivity was 50-70 mS, and applying a positive electrode potential of 3.5 V for 2 seconds, a shunt portion of electroconductive layer was decomposed selectively. Due to this process, the shut resistance of the photovoltaic element was improved to 50-200 kOMEGA.cm2. A polymeric material formed by bonding a polymer component obtained from polymerization of monomers having vinyl group with polysiloxane, was mixed with a coating material comprising acrylic resin as cross-linking material. The coating material was stirred and sprayed on the light receiving plane side of the photovoltaic element and heated for 10 minutes at 180degreesC for curing. An optical diffusion layer with the average film thickness of 20 mum was formed. The photovoltaic element was found to have excellent initial total light transmittance, weatherability and thermostability.