NOVELTY - A solar cell (10) comprises a n-type semiconductor layer (4) and a p-type semiconductor layer (8), sandwiched between two electrically-conductive layers (3b, 7b), such that the n-type and p-type semiconductor layers form a junction (11); where at least one of the electrically-conductive layers has a pattern that forms a three-dimensional relief, which is in contact with the semiconductor layer. The n-type and p-type semiconductor layers contain nanoparticulate semiconductor material.    USE - As a solar cell useful in solar module (claimed); useful as photovoltaic solar cell.    ADVANTAGE - The solar cell/module simultaneously possesses good light transmission and power generation characteristics. The patterning of electrically-conductive layer(s) provides a high aspect ratio for the electrically-conductive layers and the semiconductor layers coated on it. High aspect ratio leads to better photovoltaic generation, while keeping the layers thinner. Thus, the surface area contact between the semiconductor layer and the electrically-conductive layer is increased, while reducing the volume of materials used in the layers. The solar cell and solar module are fabricated cost effectively. The fabrication permits better control over patterning of layers; and provides graded structure that allows efficient charge transport towards top and bottom electrodes. By selecting pattern parameters such as distance between patterns, distance between pattern elements, shape of pattern elements and depth of pattern, it is possible to tune and optimize light transmission through the cell, photovoltaic power generation, and balance between light transmission and photovoltaic power generation.    DETAILED DESCRIPTION - A solar cell (10) comprises a n-type semiconductor layer (4) and a p-type semiconductor layer (8), sandwiched between two electrically-conductive layers (3b, 7b), such that the n-type and p-type semiconductor layers form a junction (11); where at least one of the electrically-conductive layers has a pattern that forms a three-dimensional relief, which is in contact with the semiconductor layer. The n-type and p-type semiconductor layers contain nanoparticulate semiconductor material. The electrically-conductive layers comprise a metallic material and/or a transparent conductive material. The pattern preferably has triangularly-shaped pattern elements. The solar cell further comprises transparent substrate(s) (1, 5) between which the semiconductor layers and the electrically-conductive layers are placed; at least one current collector layer (2) between the substrate and the electrically-conductive layer; and at least one barrier layer (6) for separating the substrate from the other layers of solar cell. An INDEPENDENT CLAIM is included for fabricating a solar cell involving providing two electrically-conductive layers; patterning at least one of the electrically-conductive layers, on one/both sides, with pre-determined pattern(s), to form a three-dimensional relief; providing n-type and p-type semiconductor layers made of nanoparticulate semiconductor material, on the electrically-conductive layers; and forming the solar cell by bringing the n-type semiconductor layer into contact with the p-type semiconductor layer.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a process for design and fabrication of a single transparent photovoltaic cell.    Transparent glass substrates (1, 5)    Current collector layer (2)    Patterned electrically-conductive layers (3b, 7b)    N-type semiconductor layer (4)    Barrier layer (6)    P-type semiconductor layer (8)    Photovoltaic solar cell (10)    Three-dimensional heterojunction. (11)