[en] Full text: The use of new and renewable sources of energy has received great attention, and this has led to an increase in the number of researches on solar cells in the last decades. Among the solar cell types, the quantum dots sensitized ones (QDSSCs) stand out, since the QDs have high extinction coefficient, multiple exciton generation, bandgap control and simple synthesis process [1]. To improve the performance of QDSSCs, it is necessary that a fast electron discharge in the counter electrodes (CE) occurs, to guarantee the maximum potential of open circuit (Voc). In this sense, the carbon dots (CDs) are very promising luminescent nanomaterials, due to their chemical and biological stability, absence of toxicity and high solubility in polar and nonpolar solvents, which make them suitable to be applied as counter electrodes in QDSSCs. In this work the CDs were synthesized by pyrolysis of tartaric acid, tartaric acid / HMTA and tartaric acid / GSH at 270 °C, under inert atmosphere. In addition, the synthesized materials were incorporated into polyaniline, to be used as CEs in quantum dot sensitized solar cells. CDs functional groups were characterized by infrared spectroscopy, resulting in groups of carboxylic and nitrogenous components, consistent with the used precursors, and also confirmed by XPS. The CDs exhibited excitation wavelength dependent emission, with higher intensity in the blue and absorption in the UV region. The CdS solar cells prepared with CDs in the CE presented higher efficiency values than the standard cells, reaching values of 3.24% of energy conversion efficiency. Reference: [1] Twidell, J.; Weir, T.; Renewable Energy Resources. Routledge, 2015. (author)