A facile polymer-assisted direct deposition method is reported for fabrication of transparent WO3 films for photoelectrochemical water oxidation. Addition of Triton X114 as a polymer additive brings a significant impact on morphology, optical property and crystallinity of WO3 film that leads to improved photoelectrochemical activity. An optimum amount of Triton X 114 added during the WO3 synthesis makes a photoanode with near glass-like transparency with activity improvement. Moreover, bulk charge separation efficiency as high as 80% at 1.23 V-RHE is obtained by Triton X 114 addition by forming preferentially (200) oriented WO3 crystals of better bulk charge transfer property. (C) 2016 Elsevier B.V. All rights reserved.