"The objective of the present project is a development of approaches for facile colloidal synthesis of Cu-containing semiconductor nanocrystals, characterized by low production cost, high stability, high photoluminescence efficiency and low toxicity. The materials that will be synthesized will undergo comprehensive physico-chemical characterization including a deep assessment of their toxicity and will be evaluated as light absorbing components for fabrication of excitonic solar cells.Copper chalcogenides represented by binary, ternary and quaternary compounds, like CuS(Se,Te), CuIn(Ga)S(Se,Te), CuZnSnS(Se,Te) are one of the most attractive series of low-toxic semiconductor materials, which are truly alternative to the widely studied cadmium, mercury and lead chalcogenides. This new generation of semiconductor nanocrystals is now being in the focus of a great scientific interest. These nanocrystals are characterized by tunable visible and near infrared emission and absorption properties and high extinction coefficients and therefore hold great promise in bio applications, in light emitting diodes fabrication, photovoltaics and optoelectronics.This project will provide new knowledge into the mechanisms governing the reactions involving the various precursors during the stages of nanoparticle nucleation. This new knowledge will then allow for a proper control of nanoparticles crystal structure, composition, size, shape, and consequently of their optoelectronic and photovoltaic properties. The synthesized and fully characterized copper chalcogenide nanoparticles will be used for fabrication of solar cells. Combination and adaptation of state-of-the-art approaches as well as creation of novel synthetic methods will result in innovative investigation covering wide range of tasks from the synthesis of novel materials through their comprehensive characterization and ending with their application in photovoltaics."