Inkjet printing of tungsten sol-gel ink

Tungsten (VI) oxide − WO3 is one of the widely studied inorganic semiconductors with outstanding chromogenic properties. Its unique optical and electrical properties enable application in energy efficient systems (e.g. smart windows), sensors, displays, storage units, electric and photo catalysts and solar cells. The WO3 layers are mostly made by expensive vacuum sputtering (PVD), chemical vapour deposition (CVD) and electro-deposition, but it is also possible to deposit layers from sol-gel solutions using dip-coating or spin-coating. On the other hand printing of the WO3 layers is unexplored area, although enabling flexibility of the substrates, patterning, multi-layer deposition and R2R mass production favouring low cost of the final devices. According to our knowledge this is the first report showing the feasibility of inkjet printing of tungsten sols.