Effects of SiO₂ and TiO₂ on resistance stabilities of flexible indium-tin-oxide films prepared by ion assisted deposition

Inorganic buffer layers such as SiO₂ or TiO₂ and transparent conductive indium-tin-oxide (ITO) films were prepared on polyethylene terephthalate (PET) substrates by ion assisted deposition (IAD) at room temperature, and the effects of SiO₂ and TiO₂ on the bending resistance performance of flexible ITO films were investigated. The results show that ITO films with SiO₂ or TiO₂ buffer layer have better resistance stabilities compared to ones without the buffer layer when the ITO films are inwards bent at a bending radius more than 1.2 cm and when the ITO films are outwards bent at a bending radius from 0.8 cm to 1.2 cm. ITO films with SiO₂ buffer layer have better resistance stabilities compared to ones with TiO₂ buffer layer after the ITO films are bent several hundreds of cycles at the same bending radius, for the adhesion of SiO₂ is stronger than that of TiO₂. The compressive stress resulted from inward bending leads to the formation of more defects in the ITO films compared with the tensile stress arising from outward bending. SiO ₂ and TiO₂ buffer layers can effectively improve the crystallinity of ITO films in (400), (440) directions.