Study of structural, wettability, optical and electrical properties of fluorine doped SnO2 (F-SnO2) sprayed thin films

SnO2:F thin films were successfully deposited onto glass substrates using a low-cost spray pyrolysis technique. The influence of fluorine concentration on the structural, morphological, optical, wettability, and electrical properties of the films was systematically investigated. X-ray diffraction and Raman spectroscopy analyses confirmed the formation of single-phase polycrystalline SnO2 films with a tetragonal rutile structure and a preferential orientation along the (200) plane. Surface wettability studies revealed hydrophilic behavior for all samples with contact angle values lower than 90°. Optical measurements showed high transparency in the visible region, with average transmittance ranging from approximately (71 ± 0.5) % to (81 ± 0.5) %, while the film doped with 6% fluorine exhibited the highest transparency. The optical band gap increased from (3.75 ± 0.02) eV to (3.87 ± 0.02) eV with increasing fluorine concentration, and the highest optical band gap value of (3.87 ± 0.02) eV was obtained for the 6% F-doped film. Electrical measurements demonstrated a significant improvement in conductivity upon fluorine doping, reaching a high conductivity of (14.057 ± 0.5) Ω–1.cm–1 for the 6% F-doped film. The obtained results show that SnO2:F thin films prepared by spray pyrolysis have high optical transparency and high electrical conductivity, which makes them promising candidates for transparent conducting oxide (TCO) applications in optoelectronic and photovoltaic devices.