NOVELTY - A solar cell (100) comprises: first electrode (104) deposited onto a transparent substrate (102); a grating (106) formed onto the first electrode; an active layer (112) deposited onto the grating, the active layer configured to convert photonic energy into electrical energy; and a second electrode (114) deposited onto the active layer, where the grating is configured to enhance light absorption by the active layer.    USE - As a solar cell such as organic solar cell, used as power conversion device.    ADVANTAGE - The solar cell has improved power-conversion efficiency over a conventional flat solar cell.    DETAILED DESCRIPTION - A solar cell (100) comprises: first electrode (104) deposited onto a transparent substrate (102); a grating (106) formed onto the first electrode; an active layer (112) deposited onto the grating, the active layer configured to convert photonic energy into electrical energy; and a second electrode (114) deposited onto the active layer, where the grating is configured to enhance light absorption by the active layer. The solar cell further comprises transparent, electrically-conducting layer disposed between the grating and the active layer, the transparent, electrically-conducting layer provided to improve the electrical connection between the active layer and the first electrode; and hole-conducting film disposed between the transparent, electrically-conducting layer and the active layer. The hole-conducting film comprises poly (3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrene sulfonate) (PSS). The active layer comprises a bulk hetero-junction organic photovoltaic material (preferably blend of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM)). The first electrode comprises a layer of indium tin oxide. The second electrode comprises a layer of aluminum.    DESCRIPTION OF DRAWING(S) - The figure shows a simplified view of structure of photoresist (PR) grating based solar cell.    Solar cell (100)    Transparent substrate (102)    First electrode (104)    Grating (106)    Active layer (112)    Second electrode (114)