This work reports the photocatalytic activity of undoped tin oxide (TO) and F doped tin oxide (FTO) thin films for MB dye degradation under visible light irradiation. A facile homemade jet nebulizer spray pyrolysis technique was employed to prepare these samples. The results indicate that FTO film exhibits superior photocatalytic activity compared to TO film. Dye degradation of nearly 95\% is achieved using FTO film at 90 min whereas TO film degrades only 78\% of dye molecules in the same time interval. This enhancement for FTO films might be due to the generation of large number of free electrons caused by the fluorine incorporation. The mechanism behind the enhancement of photocatalytic activity of FTO films is discussed elaborately with the aid of optical and PL studies. The structure, composition and morphology of the samples were analyzed using XRD, XPS, FTIR, FESEM and AFM. The incorporation of F into SnO2 lattice is confirmed through FTIR analysis. (C) 2017 Elsevier Ltd. All rights reserved.