Study of Structural and Optical Properties of WO3- Polyaniline Thin films Developed by Chemical Bath Deposition Method

In the present research work, WO₃–Polyaniline (PANI) thin films were successfully prepared on glass substrates using the chemical bath deposition (CBD) method. The structural and optical properties of the films were systematically investigated using FESEM, EDX, XRD, FTIR, and UV–Vis spectroscopy. The XRD analysis revealed distinct diffraction peaks corresponding to monoclinic WO₃ (JCPDS No. 83-0950), along with a broad hump attributed to the semi-crystalline nature of PANI, confirming the formation of an organic–inorganic hybrid structure. The calculated average crystallite size was found to be approximately 15.6 nm, indicating the nanocrystalline nature of the composite film. FESEM images showed agglomerated nanostructures with irregular shapes and porous morphology, while the BET analysis estimated a specific surface area of 3.68 m²/g, favoring enhanced interfacial interactions. EDX spectra confirmed the elemental composition with the presence of tungsten, oxygen, and carbon, validating the successful incorporation of WO₃ and PANI into the composite. FTIR analysis further supported the hybrid structure by identifying characteristic vibrational bands of both WO₃ (W–O–W stretching) and PANI (C–N, C=C, and N–H vibrations). Optical studies from UV–Vis spectroscopy revealed strong absorption in the UV–visible region, and the Tauc plot estimated the direct optical band gap to be 3.2 eV. The combined structural and optical outcomes demonstrate that WO₃–PANI thin films exhibit nanocrystalline, porous, and semiconducting features, making them promising candidates for optoelectronic, electrochromic, and solar cell applications.