In recent years, polymeric nanomaterials have attracted much attention to the fields of optoelectronics and energy storage due to their unique properties. In this study, to improve limitations, such as moderate conductivity and limited stability of polyaniline (PANi), PANi /WO3 nanocomposites with different amounts of tungsten trioxide nanoparticles (2,5, 5 and 10 wt%) were synthesized and investigated. The samples were prepared using the rotation coating method and evaluated in structural tests (XRD, FTIR, FESEM), optical (UV-Visible, PL) and photosensitivity. The results showed that the presence of WO3 caused a gradual decrease in the energy band gap from 3.04 eV in pure PANi to 2.37 eV in the 10 wt% sample, which led to facilitating electron transport and improving the optoelectronic properties. FESEM images have not revealed significant changes in morphology, but FTIR and XRD spectra confirmed the simultaneous presence of polymeric and inorganic phases. The photosensitive test showed that the addition of WO3 significantly increased the photo-responsiveness; In particular, the 10 wt% sample with low energy gap exhibited the largest photosensitive response in all investigated wave lengths (415–710 nm). These improvements indicate that PANi/WO3 nanocomposites, especially in higher WO3 concentrations, are a promising candidate for various applications, including solar cells, photodetectors, images and sensors.
