Solar cells based on today’s technology are limited to power conversion efficiency around 30%. To achieve mass deployment of photovoltaic systems there is the need to lower the actual production costs and one way to do so is to produce solar cells with very high efficiencies. Intermediate band solar cells are, in theory, limited to efficiencies as high as 60% and they can be prepared by incorporating quantum dots in a matrix material. The purpose of this proposal is to prepare intermediate band solar cells based in quantum dots of chalcopyrite materials. Chalcopyrites were chosen because they are known to have good optoelectronic and material properties as demonstrated by their performance when used in thin film solar cells. Solar cells based in chalcopyrites exhibit the highest performance of all the thin film solar cells.To achieve this proposed aim the project is structured in three objectives. The first one is the preparation of chalcopyrite quantum dots using molecular beam epitaxy, the second one deals with the choice and growth of a suitable matrix material and the last one consists in bringing these two parts together and creating a solar cell stack. The candidate has a sound experience in chalcopyrite thin film solar cells and will be trained in the cross-disciplinary areas of preparation, characterization, and theory of nanostructures based in quantum dots.The main objectives are therefore:(1) Development of controlled growth of chalcopyrite-type QDs, and tuning their optoelectronic properties for suitable application in photovoltaic energy conversion(2) Development of a suitable matrix material(3) Tuning the properties of the interface between QDs and matrix to provide the basis for efficient photovoltaic energy conversion.A successful outcome will make significant progress in the knowledge of very high efficiency photovoltaic.