Abstract: Polyolefin polymeric packaging film is provided with a structure varying across its thickness from monolithic to porous with a density gradient ranging from .rho. to (1/2 to 1/4).rho., where .rho. is the density of monolithic polyolefin. The packaging film is characterized by a varying structure across its thickness. Such a film possesses the functions of a multi-layer film, but has none of the disadvantages of the latter associated with different adhesion of the layers, possible delamination in the course of storage and use, as well as the complex manufacturing process of a multi-layer film. The gradual transition of the porous structure of polyolefin to the poreless one from one surface of the film to another ensures distribution of liquid-phase specific additives along the film thickness.

Abstract: A solar cell having an active zone made of a polar polymeric film material is disclosed. The electric contacts on the surfaces of the active zone are made of metals differing in electrochemical potentials. At least one of the electric contacts has a coating that absorbs solar radiation. The absorbent coating is preferably applied to the electric contact in the form of a polymeric material whose shape approximates a hemisphere. The active zone surface and the electric contact surface free of hemispherical portions are provided with an absorbent coating made of a material whose absorbing capability is different from that of the material of the hemispherical portions.