In this study, an original hybrid technique based on rapid thermal annealing (RTA) and chemical vapor deposition (CVD) was used to synthesis MoS2 and MoO3:MoS2 hybrid thin films at low temperature on indium tin oxide (ITO). We show that using the annealing temperature, the annealing duration and the sulfur partial pressure as parameters, it is possible to switch from MoO3 (20-25 nm) to MoS2 directly without any intermediate compositions. The XPS analysis revealed a complete sulfidation at 380 degrees C without any deterioration of the ITO conductivity. Then, we synthesized thinner hybrid films (3nm) of MoO3:MoS2 in order to be used as anode buffer layer (ABL) in planar organic solar cells (PHJ-OPVs). We have demonstrated that the hybrid ABLs that appear best suited for use in PHJ-OPVs are those with high MoO3/MoS2 molecular ratio which have been treated around 210 degrees C. The introduction of the hybrid ABL with 5% of MoS2 in the PHJ-OPVs based Aluminum Phthalocyanine Chloride and Fullerene leads to a significant improvement of the OPV efficiency from 1.29% to 2.49%, this was explained by the complimentary advantages of MoO3 and MoS2.