The present study demonstrates the possibility for improving the performance of dye sensitized solar cell (DSSC) only by minimizing the loss in fill factor (FF) and maximum power point (P-MAX) which can be achieved by passivating the nanocrystalline titanium dioxide (TiO2) using physical vapor deposited molybdenum trioxide (MoO3) thin films. The effect of MoO3 coated TiO2 on charge carrier transport was examined in resulting DSSCs and observed that similar to 14% enhancement in efficiency is possible for 5 min passivation of MoO3 on TiO2. The physical vapor deposited MoO3 films were similar to 75% transparent in the spectral range of 350-800 nm with an optical bandgap of similar to 3.1 eV. The wide bandgap MoO3 films facilitate the incoming photons to reach the sensitizing dye to generate excitons. The 14% enhancement in the performance of DSSC by MoO3 passivation is observed through improving only the FF and P-MAX while it does not contribute anything significantly to current density and open circuit voltage. Electrochemical impedance spectroscopic studies further confirmed these observations through photoelectron lifetime, which remains constant both in the bulk of pristine TiO2 and MoO3 passivated TiO2 and it further confirms the effect of MoO3 passivation on FF and P-MAX in DSSCs. (C) 2018 Elsevier B.V. All rights reserved.