Titanium dioxide phases are important due to their special potential for use in a broad range of applications particularly low-cost solar cells. However, this potential is actually restricted by the wide band gaps of TiO2 phases. A way to overcome this limitation is to reduce the band gap by incorporating nonmetal dopants into TiO2. For this purpose, in this paper, the effect of F and N doping on different sizes of rutile TiO2 quantum dots (QDs) was investigated using density functional theory (DFT) calculations. The results indicated that unlike nitrogen, doping of fluorine increases the efficiency of the quantum dot solar cells as a consequence of reducing auger recombination. Moreover, it was observed that when the size of QDs increases, shifting of the Fermi level towards the conduction band occurs as a favorable effect for solar cells. (C) 2017 Elsevier B.V. All rights reserved.