Polyimide resin composition for use in forming reverse reflecting layer in photovoltaic cell and method of forming reverse reflecting layer in photovoltaic cell used therewith

A method of forming a back reflection layer in a solar cell, said method comprising

• coating a base layer on the back surface of said solar cell with a polyimide resin composition comprising an organic solvent, a polyimide resin having at least one group selected from the group consisting of alkyl groups and perfluoroalkyl groups in recurring units thereof, said polyimide resin being dissolved in said organic solvent, and light-reflecting metal oxide particles selected from the group consisting of silica (SiO2), zirconia (ZrO2), tantalum(V) oxide (Ta2O2), titanium oxide (TiO2), zinc oxide (ZnO2), and vanadium dioxide (VO2), said particles being dispersed in said organic solvent, wherein said organic solvent is a mixed solvent comprising a hydrophobic organic solvent having a vapor pressure at room temperature of 1 mm Hg or lower and a hydrophilic organic solvent having a vapor pressure at room temperature of 1 mm Hg or lower, and
• drying the resultant to form a polyimide film.