Transparent conducting thin films of fluoro doped tin oxide (FTO) deposited using inkjet printing technique

FTO thin films were successfully prepared by inkjet printing technique. FTO precursor was prepared by reacting SnCl<inf>4</inf>.5H<inf>2</inf>O and NH<inf>4</inf>F at 60°C in a sealed container. The number of layers was set up from two to five layers on the glass substrate and was deposited at room temperature around 25 to 27° C, 40° C and 60° C to determine the optimum properties for thin films performance. Morphology analysis study using VP-SEM shows the existence of fine grains with the size ranging 20 to 30 nm and the existence of crystal shape with the increases of deposition temperature. Fluorine concentration in the thin films determined from XPS analysis shows the ratio of[F]/[Sn] at 0.02 with the Sn d<inf>5/2</inf> Sn 4+, O<inf>1s</inf> as O^2-, and F1s as Sn-F bond peaks at binding energy 486.6 eV, 530.5 eV and 684.4 eV. The optical transmittance analysis showed the deposition temperature improved the optical transmittance; 60% T at ambient to 80% T at 60° C. The optimum optical transmittance was 91% T for the thin film deposited at 40° C. The sheet resistances were 16 Ω/□, 21 Ω/□ 23 Ω/□ for the thin film deposited at 40° C, ambient temperature and 60° C.