Figure 3

Examples of multilayers created using the soap-film coating method.

(a) SFC-coated dye-sensitised solar cell (DSSC). The graph shows the initial current density when the DSSC was subjected to light. A maximum of 540 mV and 12 mA under 250 mW projector lamp were detected. The energy conversion rate was ~2.8% at a cell area of 0.38 cm² and ~0.9% at 3.04 cm². The inset shows the TiO₂, the graphite-coated FTO glass and the structure of the DSSC. The photo shows the assembled DSSC. (b) The structure of the electrochromic device and the colour of the WO₃ film before and after a 4 V bias was applied to the FTO electrodes. (c) Nanoparticle crystal of 240 nm silica nanoparticles on a glass slide (10 coating cycles, 14 wt% particles, 8 cm/s), which exhibits an absorbance peak at 405 nm. The inset shows a photo of this crystal with a light-blue colour. These types of crystals might be explored for photonic crystal implementations. (d) Charge and discharge curves of a supercapacitor produced from SFC-coated 50 nm thick GO films, where the GO films were coated onto two silver foil electrodes and annealed at 400°C. (e) Free-floating graphene oxide (GO) film coated with the SFC method. The 5 μm × 5 μm AFM image shows a 2.6 nm thick GO film, which was the thinnest film that can be separated from the substrate without rupturing the film. The photo (inset, bottom left) shows the 2.6 nm thick GO film floating on the surface of an ammonia solution after being annealed at 240°C and separated from a silicon wafer. The film had a 95% transmittance at 550 nm (inset, top right).