Significant advancement in photoelectrochemical water splitting current is observed using uniquely evolved n/n junction bilayered nano-hetero-structured thin films, WO3/Yb-Mo-BiVO4, as photoanode. Films, synthesized over F:SnO2 glass substrates were characterized by UV–Visible spectroscopy, X-ray diffractometry, atomic force microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Using thin films (2% Mo and 4% Yb incorporation) as working electrode in PEC cell, in conjunction with platinum counter electrode, saturated calomel reference electrode, aqueous solution (200 cm3) of K2HPO4 (1.0 M, pH 8.7, temperature 31 ± 3.6 ℃) and 150 W Xenon Arc lamp for illumination, ~227–950% increase in Iph is recorded against monolayered pristine films of WO3 and BiVO4. Marked rise in photoelectrochemical cell photocurrent is attributable to expanded absorption of light, coupled with internal electric field in Yb–Mo-incorporated n/n hetero-junction films, reduced electrical resistivity and optimally raised surface roughness that favoured the separation and transfer of photogenerated charge carriers across electrode/electrolyte interface.